UNIT 3 PLANTS

Plants are living things that are made up of cells. They need air, water, soil, and sunlight to live. They cannot move from place to place, but their leaves move to catch the sun and their roots move towards water. Their seeds can be carried by animals or blown by the wind. We get food from all different parts of the plant: flowers, fruits, vegetables, seeds, nuts, stems, and leaves. Grass gives us a cool, soft place to walk. Some plants give us medicine, and trees are used to make paper and furniture.

Plants are living organisms belonging to the kingdom Plantae. They include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The scientific study of plants is known as botany. As of 2010, botanists have identified more than 315,000 species of plants, of which 281,821 are flowering, 12,000 are ferns and fern allies, and 16,236 are bryophytes.  Green plants, sometimes called Viridiplantae, obtain most of their energy from sunlight via photosynthesis. This process uses chlorophyll contained in chloroplasts, which gives plants their green color.

Plants are alive, just like people and animals. How do we know this? Living things all do certain things:

They grow and die.

They need energy, nutrients, air, and water.

They produce young.

They are made up of cells.

They react to what's around them.

Importance

The study of plant uses by people is termed economic botany or ethnobotany; some consider economic botany to focus on modern cultivated plants, while ethnobotany focuses on indigenous plants cultivated and used by native peoples. Human cultivation of plants is part of agriculture, which is the basis of human civilization. Plant agriculture is subdivided into agronomy, horticulture and forestry.

Food

Much of human nutrition depends on land plants, either directly or indirectly.

Human nutrition depends to a large extent on cereals, especially maize (or corn), wheat and rice. Other staple crops include potato, cassava, and legumes. Human food also includes vegetables, spices, and certain fruits, nuts, herbs, and edible flowers.

Beverages produced from plants include coffee, tea, wine, beer and alcohol.

Sugar is obtained mainly from sugar cane and sugar beet.

Cooking oils and margarine come from maize, soybean, rapeseed, safflower, sunflower, olive and others.

Food additives include gum arabic, guar gum, locust bean gum, starch and pectin.

Livestock animals including cows, pigs, sheep, and goats are all herbivores; and feed primarily or entirely on cereal plants, particularly grasses.

Nonfood products

Wood is used for buildings, furniture, paper, cardboard, musical instruments and sports equipment. Cloth is often made from cotton, flax or synthetic fibers derived from cellulose, such as rayon and acetate. Renewable fuels from plants include firewood, peat and many other biofuels. Coal and petroleum are fossil fuels derived from plants. Medicines derived from plants include aspirin, taxol, morphine, quinine, reserpine, colchicine, digitalis and vincristine. There are hundreds of herbal supplements such as ginkgo, Echinacea, feverfew, and Saint John's wort. Pesticides derived from plants include nicotine, rotenone, strychnine and pyrethrins. Drugs obtained from plants include opium, cocaine and marijuana. Poisons from plants include ricin, hemlock and curare. Plants are the source of many natural products such as fibers, essential oils, natural dyes, pigments, waxes, tannins, latex, gums, resins, alkaloids, amber and cork. Products derived from plants include soaps, paints, shampoos, perfumes, cosmetics, turpentine, rubber, varnish, lubricants, linoleum, plastics, inks, chewing gum and hemp rope. Plants are also a primary source of basic chemicals for the industrial synthesis of a vast array of organic chemicals. These chemicals are used in a vast variety of studies and experiments.

Aesthetic uses

Thousands of plant species are cultivated for aesthetic purposes as well as to provide shade, modify temperatures, reduce wind, abate noise, provide privacy, and prevent soil erosion. People use cut flowers, dried flowers and houseplants indoors or in greenhouses. In outdoor gardens, lawn grasses, shade trees, ornamental trees, shrubs, vines, herbaceous perennials and bedding plants are used. Images of plants are often used in art, architecture, humor, language, and photography and on textiles, money, stamps, flags and coats of arms. Living plant art forms include topiary, bonsai, ikebana and espalier. Ornamental plants have sometimes changed the course of history, as in tulipomania. Plants are the basis of a multi-billion dollar per year tourism industry which includes travel to arboretums, botanical gardens, historic gardens, national parks, tulip festivals, rainforests, forests with colorful autumn leaves and the National Cherry Blossom Festival. Venus Flytrap, sensitive plant and resurrection plant are examples of plants sold as novelties.

Scientific and cultural uses

Tree rings are an important method of dating in archeology and serve as a record of past climates. Basic biological research has often been done with plants, such as the pea plants used to derive Gregor Mendel's laws of genetics. Space stations or space colonies may one day rely on plants for life support. Plants are used as national and state emblems, including state trees and state flowers. Ancient trees are revered and many are famous. Numerous world records are held by plants. Plants are often used as memorials, gifts and to mark special occasions such as births, deaths, weddings and holidays. Plants figure prominently in mythology, religion and literature. The field of ethnobotany studies plant use by indigenous cultures which helps to conserve endangered species as well as discover new medicinal plants. Gardening is the most popular leisure activity in the U.S. Working with plants or horticulture therapy is beneficial for rehabilitating people with disabilities. Certain plants contain psychotropic chemicals which are extracted and ingested, including tobacco, cannabis (marijuana), and opium.

Negative effects

Weeds are plants that grow where people do not want them. People have spread plants beyond their native ranges and some of these introduced plants become invasive, damaging existing ecosystems by displacing native species. Invasive plants cause billions of dollars in crop losses annually by displacing crop plants, they increase the cost of production and the use of chemical means to control them affects the environment.

Plants may cause harm to people and animals. Plants that produce windblown pollen invoke allergic reactions in people who suffer from hay fever. A wide variety of plants are poisonous to people and/or animals. Toxalbumins are plant poisons fatal to most mammals and act as a serious deterrent to consumption. Several plants cause skin irritations when touched, such as poison ivy. Certain plants contain psychotropic chemicals, which are extracted and ingested or smoked, including tobacco, cannabis (marijuana), cocaine and opium. Smoking causes damage to health or even death, while some drugs may also be harmful or fatal to people.[29][30] Both illegal and legal drugs derived from plants may have negative effects on the economy, affecting worker productivity and law enforcement costs.[31][32] Some plants cause allergic reactions in people and animals when ingested, while other plants cause food intolerances that negatively affect health

The Plant Kingdom

The Plant Kingdom is a way to classify (or organize) plants. They are divided into groups based on the traits they have in common. Scientists change the way plants are classified from time to time, when they discover new types of plants or learn new things about plants.

The two main groups are vascular plants (plants that use stems and veins to transport food and water), and non-vascular plants (plants with no roots, stems, or leaves).

Vascular plants can divided into smaller groups, one of which is seed plants. This group includes flowering and non-flowering plants.

Flowering plants include monocots (one seed leaf) and dicots (two seed leaves). The non-flowering plants can also be divided into several groups, including cycads, conifers, and ginkgo.

About Non-Flowering Plants

All green plants that have flowers are called flowering plants. Scientists have grouped these according to the number of seed leaves found in each plant.

Monocots (or monocotyledons) have one seed leaf; dicots (or dicotyledons) have two seeds leaves. These leaves provide the food the young plant needs until it can make its own food. Flowering plants consist of four main parts: (1) roots, (2) stem, (3) leaves, and 4) flowers.

Plants without flowers are called non-flowering plants, or gymnosperm. While they do produce seeds, the seed is not enclosed in a flower (and eventually a fruit) the way seeds are in flowering plants.

Non-flowering plants are very common, and include conifers (evergreens), cycads, and ginkgo. Popular types of conifers include fir and pine trees. These trees are characterized by sharp needles and produce cones that hold the seeds.

There are two different types of trees: non-flowering trees that have seeds that are not enclosed, and flowering trees that have seeds that are enclosed. An example of a non-flowering tree would be an pine tree. An example of a flowering tree would be a fruit tree, such as peach or orange.

Flowering trees are deciduous; that is, they shed their leaves every year. Other trees are conifers; they grow new leaves before shedding old ones, and stay green all year round (“evergreen”). Trees consist of roots, trunk (stem), branches, twigs, and leaves. The tallest trees in the world are the redwoods of

Some of the food we eat comes from roots, like carrots, beets, turnips, radishes, and potatoes. These are roots that store food for the growing plant. Radishes—an edible root.

Leaves help plants make their own food. Within the leaf is a green material called chlorophyll. Chlorophyll absorbs sunlight to make a natural sugar that the plants uses for food. This process is called photosynthesis. During photosynthesis, carbon dioxide is used by the plant, and oxygen is released. This makes trees and plants a great way to keep the air on earth fresh and clean.

The leaf has veins for carrying this sugar to other parts of the plant. The flat, green part of the leaf is called the blade. The edge of the leaf is called the margin. A good nickname for leaves is “suncatchers”, because they catch the sun that the plant needs

to make food. In the fall, leaves lose their chlorophyll. That allows the other colors in the leaf to show, so that we see yellow, orange, red, and even purple leaves.

Plants use flowers to reproduce (make more of themselves). The flower’s job is to produce a fruit, which contains seeds. Flowers are used by humans to add beauty to outdoor and indoor areas, and some flowers can also be eaten.

Flowers, or blossoms, are made up of petals, called the corolla, which are usually brightly colored. The bright colors attract birds and insects, who spread pollen from one flower to another. This fertilizes the seeds and allows new plants to grow. Other parts of the flower include the calyx, the green leaves that surround the petals; the stamen, which produces the pollen; and the pistil, which receives the pollen from another flower to fertilize the plant.

Many plants use seeds to reproduce. A plant produces a very small version of itself, called an embryo. This embryo, together with its stored food, is covered with a thin covering called the testa (seed coat). The embryo, stored food, and testa make up the seed. This seed will grow into a new plant. The seed uses the stored food to grow until it is big enough to make its own food, using its leaves. The seed coat protects the seed until it is ready to grow. For a seed to germinate (start to grow), it needs to be in moist soil. The water causes the testa to split apart. Then the root tip of the seeds can grow into the ground. Plants spread their seeds in many ways. Some seeds are blown by the wind; others are carried by insects, birds, or mammals. Nuts, a type of seed, are often buried in the ground by animals and some result in new plants. Some seeds fall into water and are carried to new places. Some plants grow a covering for their seeds. This ripened part of the seed is called fruit. Tomatoes, apples, and peaches are some of the plants that grow in this way. Vegetables are actually the fruit part of the plant. Generally, the ripened part of the plant is called “fruit” if it is sweet, and “vegetable” if it is savory, or less sweet. The outer skin of the fruit is called the exocarp. The fleshy part of the fruit, the part we eat, is called the mesocarp. The inner part of the fruit that covers the seeds is called the endocarp. All three of these layers put together are called the pericarp. Humans and animals use fruits and vegetables as a great source of food. Most fruits can be eaten raw, although they can also be cooked or baked. Vegetables generally taste better after being cooked.

There are several different types of stems. Flowering plants like carnations and tomatoes have soft stems. Trees and bushes have hard, woody stems. Woody stems have an outer covering called bark. Underneath the bark is a layer of growing cells called cambium. Every year, trees grow another layer of cambium. Counting these layers (or rings) tells you how old the tree is.

The stem of a plant has four main jobs: (1) to support the leaves, flowers, and fruit of the plant; (2) to act as a highway, bringing water and nutrients to the plant; (3) the storage of food for the plant; (4) producing new living tissue for the plant.

Some stems are edible—asparagus and celery are two examples.

The four types of plants and their role

Four types of edible plants are available for conducting a grazing enterprise. They are annuals, perennial grasses, perennial edible shrubs and fodder trees. Each type is very different in so many ways, with each type having a specific role. Those who have managed in both good and bad years, quickly come to realise that there was no such thing as the best plant. In good years the most productive plants are most appreciated and in the bad years the hardy ones. Each type has different management requirements and each type has a particular mechanism that ensures survival.

 The four plant types animals rely on for energy and protein annuals, perennial grasses, perennial edible shrubs and fodder trees How well these different groups are understood and how well they are managed, will make or break the grazing business and the landscape. When the four plant types are discussed, it is important to remember that there are the two seasons, summer and winter. There is also extreme variation in rainfall from year to year. Just as animals need a variety of plants in the landscape for production and survival, likewise, soils function better if there is a variety of plants to allow carbon flows to be maximised over time. Nutrient cycling is more successful with a variety of plants. Some decompose quickly to release their nutrients, while others have deeper roots and are able to source nutrients that have escaped deep into the soil and return them to the surface. If there is going to be climate change, due to global warming, then the location of specific species may move further south, as that is where their ideal environment will be.  Annuals are the opportunists of the pasture system and can be either grasses or broadleaf plants. They grow rapidly from seed when moisture and nutrients allow, and escape the adverse periods. With climate change, they might become less available due to increased variability in rainfall.

Perennial grasses are less palatable than the annuals, but supply the bulk of feed over time, if they are present. Perennial grasses are our most valuable resource, as they stabilise the landscape, trap nutrients and moisture, and provide animals with a readily available long term feed reservoir.

There are two basic groups of perennial grasses, the C3 group and the C4 group. The two groups absorb carbon dioxide differently through the process of photosynthesis. The two groups have different optional growing temperatures, with the C4 group functioning better at higher temperatures. The C3 plants need higher moisture and have higher nutrient requirements. In the areas suited to both groups, which is a large area of Australia, it is management which determines the availability of the more palatable C3 grasses.

Perennial edible shrubs include a variety of species, but the focus here will be on the main type, the saltbushes (chenopods). They are drought resistant, frost resistant and kangaroos do not eat them, so they are a long term source of "green leaf". It is their deep roots of up to 4 metres, and slower growth that makes them drought resistant. They can obtain moisture at depth during dry times, like trees do. Their leaf structure reduces transpiration, which increases water use efficiency.

Saltbushes are often criticised for being less palatable than the herbages and grasses, but this is their attribute as it guarantees they are still available for animal production and survival, when all other plants have failed. They are often incorrectly promoted as a fodder supply for dry times. Their true role under these conditions is to supply protein to allow ruminant animals to digest unproductive grasses and leaves.

For many, saltbush is just part of the nostalgia of the early settlers and the outback of Australia, as we like to romanticise it. The reality is that saltbush is a management tool supplying ecosystem services to the environment. An example of an ecosystem service supplied by Old Man Saltbush is its ability to change the soil structure in degraded landscapes, and so allow more water and air in. This results in the landscape becoming a more friendly environment for grasses to then enter. With the arrival of perennial grasses between the Old Man Saltbush, there is further ongoing introduction of carbon into the landscape.

Fodder trees include the edible component of the trees in the landscape. Examples are mulga, leucaena and tree lucerne. They are able to utilise past rainfall further into the future and they are part of the reliable component of the fodder supply.

Leucaena and mulga have the added advantage of directly introducing nitrogen into the landscape. If they are not a monoculture, then they can enhance the ability of grasses to introduce more carbon into the landscape.

In a country where we have the most unreliable rainfall in the world, the emphasis must be shifted to increasing the percentage of perennial plants in the pasture, be they grasses or shrubs. It is the perennials that can respond to isolated single falls of rain, while annuals can't.

It is the perennial grasses that are best at introducing carbon into the landscape. It is the perennials that we are thinking of with the statement "carbon makes carbon". Just as having money and managing it properly leads to more money, so having perennial grasses and managing them correctly, leads to more perennial grasses, (and hence further additions of carbon).

A correct balance of plants leads to ongoing photosynthesis (carbon storage) under all seasonal and climatic conditions, with the possible exception of extreme drought.

Maximising landscape carbon and soil carbon is all about trapping sunlight at a multiple of levels. Recycling of nutrients is all about having different depths of roots to bring the nutrients to the surface. Nutrients and carbon go hand in hand. Planting fodder trees, Old Man Saltbush, or any tree, into areas of straight grass, is returning the vegetation layers, just as thinning dense regrowth and allowing grass to grow is returning a vegetation layer.

How plants function

Root growth and leaf growth are related. Therefore animal grazing affects both the leaves and the root system. Excessive removal of leaves reduces the ability of plants to build and maintain good root systems. Plants need an extensive root system in order to extract what they need to produce an abundance of fodder for animal production.

At the end of dry times, perennial grasses are dry old butts that have no green leaves to promote photosynthesis. Yet they grow with the arrival of rain, so obviously they have a mechanism to start growth after rain. We know that plant growth requires energy, so it is obvious that they must be sourcing energy from somewhere.

To explain this last point, the roots hold reserves of plant carbohydrates (starches/energy) needed to stimulate growth when growing conditions arrive. Some reserves are also held in the crown of perennial grasses. Apart from instigating growth after dormancy, these root reserves are also important for maintaining tissue during drought, when photosynthesis is not occurring.

The most dangerous time for perennial grasses is a run of marginal years when stock eat all the new growth every time there is some rain. This results in root reserves being drawn on regularly with little replacement, and so some plants eventually die. This is what David Freudenberger of CSIRO refers to it as the paradox of average years. Green pick is ongoing so root reserves are at risk.

Plants are the ultimate net workers who supply partners everywhere in order to get what they want done. Plants need food and water the same as humans. Apart from the carbon in the atmosphere being a food source, plants get the other things they need out of the soil. For this reason they have to ensure that their helpers in the soil construct a soil that is full of nutrients, water and air. These helpers either leave the construction site or die if plants do not feed them. Stressed and dying plants lead to unhealthy soil as they do not feed the below ground food chain

The carbon: nitrogen ratio

The carbon : nitrogen ratio (C:N ratio) of living things and their residues is essential for determining the outcomes of many processes. This ratio is always discussed in papers looking at landscape function and animal performance, yet it is rarely discussed in literature available to rural producers.

The first thing to understand about plants is that the carbon is fairly constant in the break-up, it is the nitrogen that varies. Most trees are about 50% carbon while grasses are about 45% carbon. Like all figures used in plant analysis, this is based on a dry weight.

As the plants are the start of the two food chains, above and below the ground, the C:N ratio of the plants will determine how efficient these other consumption processes are.

In plants, nitrogen is necessary for chlorophyll synthesis, and as part of the chlorophyll molecule, is involved in photosynthesis. It is chlorophyll that gives the plant its green colour. Lack of nitrogen and chlorophyll means that the plant will not utilise sunlight as an energy source to carry out its essential functions such as nutrient uptake. A badly managed pasture with low soil carbon levels, and hence lower nitrogen levels, struggles with carbon introduction following rain, due to a lack of nitrogen. Dysfunctional landscapes become increasingly infertile, because they have a low potential for capturing new resources.

Discussions often focus on how different plants have different nitrogen levels. However, it is also important to appreciate that the nitrogen levels vary within a plant. This is why animals, especially sheep, will select certain plant parts over others.

In the future, more attention will be placed on the C:N ratio of the diets of ruminant animals, as it influences the production of methane per kg of production.

UNIT 2 WORK AND PLAY FLOW OF MATTER AND ENERGY

However complex the workings of living organisms, they share with all other natural systems the same physical principles of the conservation and transformation of matter and energy. Over long spans of time, matter and energy are transformed among living things, and between them and the physical environment. In these grand-scale cycles, the total amount of matter and energy remains constant, even though their form and location undergo continual change.

Almost all life on earth is ultimately maintained by transformations of energy from the sun. Plants capture the sun's energy and use it to synthesize complex, energy-rich molecules (chiefly sugars) from molecules of carbon dioxide and water. These synthesized molecules then serve, directly or indirectly, as the source of energy for the plants themselves and ultimately for all animals and decomposer organisms (such as bacteria and fungi). This is the food web: The organisms that consume the plants derive energy and materials from breaking down the plant molecules, use them to synthesize their own structures, and then are themselves consumed by other organisms. At each stage in the food web, some energy is stored in newly synthesized structures and some is dissipated into the environment as heat produced by the energy-releasing chemical processes in cells. A similar energy cycle begins in the oceans with the capture of the sun's energy by tiny, plant-like organisms. Each successive stage in a food web captures only a small fraction of the energy content of organisms it feeds on.

The elements that make up the molecules of living things are continually recycled. Chief among these elements are carbon, oxygen, hydrogen, nitrogen, sulfur, phosphorus, calcium, sodium, potassium, and iron. These and other elements, mostly occurring in energy-rich molecules, are passed along the food web and eventually are recycled by decomposers back to mineral nutrients usable by plants. Although there often may be local excesses and deficits, the situation over the whole earth is that organisms are dying and decaying at about the same rate as that at which new life is being synthesized. That is, the total living biomass stays roughly constant, there is a cyclic flow of materials from old to new life, and there is an irreversible flow of energy from captured sunlight into dissipated heat.

An important interruption in the usual flow of energy apparently occurred millions of years ago when the growth of land plants and marine organisms exceeded the ability of decomposers to recycle them. The accumulating layers of energy-rich organic material were gradually turned into coal and oil by the pressure of the overlying earth. The energy stored in their molecular structure we can now release by burning, and our modern civilization depends on immense amounts of energy from such fossil fuels recovered from the earth. By burning fossil fuels, we are finally passing most of the stored energy on to the environment as heat. We are also passing back to the atmosphere—in a relatively very short time—large amounts of carbon dioxide that had been removed from it slowly over millions of years.

The amount of life any environment can sustain is limited by its most basic resources: the inflow of energy, minerals, and water. Sustained productivity of an ecosystem requires sufficient energy for new products that are synthesized (such as trees and crops) and also for recycling completely the residue of the old (dead leaves, human sewage, etc.). When human technology intrudes, materials may accumulate as waste that is not recycled. When the inflow of resources is insufficient, there is accelerated soil leaching, desertification, or depletion of mineral reserves.

Force is any influence that causes a free body to undergo a change in speed, a change in direction, or a change in shape. Force can also be described by intuitive concepts such as a push or pull that can cause an object with mass to change its velocity (which includes to begin moving from a state of rest), i.e., to accelerate, or which can cause a flexible object to deform. A force has both magnitude and direction, making it a vector quantity. Newton's second law, F=ma, can be formulated to state that an object with a constant mass will accelerate in proportion to the net force acting upon and in inverse proportion to its mass, an approximation which breaks down near the speed of light. Newton's original formulation is exact, and does not break down: this version states that the net force acting upon an object is equal to the rate at which its momentum changes.

Related concepts to accelerating forces include thrust, increasing the velocity of the object, drag, decreasing the velocity of any object, and torque, causing changes in rotational speed about an axis. Forces which do not act uniformly on all parts of a body will also cause mechanical stresses,[2] a technical term for influences which cause deformation of matter. While mechanical stress can remain embedded in a solid object, gradually deforming it, mechanical stress in a fluid determines changes in its pressure and volume.

A force is a push or pull upon an object resulting from the object's interaction with another object. Whenever there is an interaction between two objects, there is a force upon each of the objects. When the interaction ceases, the two objects no longer experience the force. Forces only exist as a result of an interaction.

For simplicity sake, all forces (interactions) between objects can be placed into two broad categories:

contact forces, and

forces resulting from action-at-a-distance

Contact forces are those types of forces that result when the two interacting objects are perceived to be physically contacting each other. Examples of contact forces include frictional forces, tensional forces, normal forces, air resistance forces, and applied forces. These specific forces will be discussed in more detail later in Lesson 2 as well as in other lessons.

Action-at-a-distance forces are those types of forces that result even when the two interacting objects are not in physical contact with each other, yet are able to exert a push or pull despite their physical separation. Examples of action-at-a-distance forces include gravitational forces. For example, the sun and planets exert a gravitational pull on each other despite their large spatial separation. Even when your feet leave the earth and you are no longer in physical contact with the earth, there is a gravitational pull between you and the Earth. Electric forces are action-at-a-distance forces. For example, the protons in the nucleus of an atom and the electrons outside the nucleus experience an electrical pull towards each other despite their small spatial separation. And magnetic forces are action-at-a-distance forces. For example, two magnets can exert a magnetic pull on each other even when separated by a distance of a few centimeters.

 Play is  defined   as “outside of ordinary life,” not serious,” and “unproductive.” Some authors attribute this work/play distinction to industrialization or to social-class distinctions. What is play’s relationship to “work”? Many scientists think of much of their work as play, often linking the idea of play with high creativity. “Play did not interrupt work,” he says, it just provided another venue for thinking. People often have more brainstorms on the jogging path than at their desks.” “Work and play have always been overlapping categories.”  It gives the following outcomes to the human being they are:

• People play at work to seek competence, stimulation, challenge, or reinforcement.

• People who perform very playful tasks enjoy what they are doing. When they judge those activities appropriate, they switch to them readily and try to continue doing them.

• They tend to concentrate more and increase their persistence.

• They become less aware of the passage of time and reluctant to change activities.

• They become so absorbed that they may neglect other things, such as long-term goals, non-playful tasks and social relations.

• Their learning is enhanced because the pleasure and involvement of playful activities induces them to expend time and effort.

• Through different forms of play they can either broaden their behavioral repertoires incrementally, discover or invent radically new behaviors, and polish their existing skills through repetitive practice.

• Playful tasks foster creativity. If the playful tasks are new ones, they will put much effort into learning them and exploring them, usually trying to control their own learning.

There is to a large extent the result of changing technology. Starbuck and Webster attribute much of the erosion of the distinction between play and work to the introduction of PCs into the workplace, since they are “simultaneously fun to use and serious tools.”

Types of forces

A force is any influence that causes a free body to undergo a change in speed, a change in direction, or a change in shape. Force can also be described by intuitive concepts such as a push or pull that can cause an object with mass to change its velocity (which includes to begin moving from a state of rest), i.e., to accelerate, or which can cause a flexible object to deform. A force has both magnitude and direction, making it a vector quantity. Newton's second law, F=ma, can be formulated to state that an object with a constant mass will accelerate in proportion to the net force acting upon and in inverse proportion to its mass, an approximation which breaks down near the speed of light. Newton's original formulation is exact, and does not break down: this version states that the net force acting upon an object is equal to the rate at which its momentum changesces

] Sir Isaac Newton sought to describe the motion of all objects using the concepts of inertia and force, and in doing so he found that they obey certain conservation laws. In 1687 Newton went on to publish his thesis Philosophiae Naturalis Principia Mathematica.[4][10] In this work Newton set out three laws of motion that to this day are the way forces are described in physics.[10]

[edit]Newton's first law

Main article: Newton's laws of motion#Newton's first law

Newton's first law of motion states that objects continue to move in a state of constant velocity unless acted upon by an external net force or resultant force.[10] This law is an extension of Galileo's insight that constant velocity was associated with a lack of net force (see a more detailed description of this below). Newton proposed that every object with mass has an innate inertia that functions as the fundamental equilibrium "natural state" in place of the Aristotelian idea of the "natural state of rest". That is, the first law contradicts the intuitive Aristotelian belief that a net force is required to keep an object moving with constant velocity. By making rest physically indistinguishable from non-zero constant velocity, Newton's first law directly connects inertia with the concept of relative velocities. Specifically, in systems where objects are moving with different velocities, it is impossible to determine which object is "in motion" and which object is "at rest". In other words, to phrase matters more technically, the laws of physics are the same in every inertial frame of reference, that is, in all frames related by a Galilean transformation.

For example, while traveling in a moving vehicle at a constant velocity, the laws of physics do not change from being at rest. A person can throw a ball straight up in the air and catch it as it falls down without worrying about applying a force in the direction the vehicle is moving. This is true even though another person who is observing the moving vehicle pass by also observes the ball follow a curving parabolic path in the same direction as the motion of the vehicle. It is the inertia of the ball associated with its constant velocity in the direction of the vehicle's motion that ensures the ball continues to move forward even as it is thrown up and falls back down. From the perspective of the person in the car, the vehicle and everything inside of it is at rest: It is the outside world that is moving with a constant speed in the opposite direction. Since there is no experiment that can distinguish whether it is the vehicle that is at rest or the outside world that is at rest, the two situations are considered to be physically indistinguishable. Inertia therefore applies equally well to constant velocity motion as it does to rest.

The concept of inertia can be further generalized to explain the tendency of objects to continue in many different forms of constant motion, even those that are not strictly constant velocity. The rotational inertia of planet Earth is what fixes the constancy of the length of a day and the length of a year. Albert Einstein extended the principle of inertia further when he explained that reference frames subject to constant acceleration, such as those free-falling toward a gravitating object, were physically equivalent to inertial reference frames. This is why, for example, astronauts experience weightlessness when in free-fall orbit around the Earth, and why Newton's Laws of Motion are more easily discernible in such environments. If an astronaut places an object with mass in mid-air next to herself, it will remain stationary with respect to the astronaut due to its inertia. This is the same thing that would occur if the astronaut and the object were in intergalactic space with no net force of gravity acting on their shared reference frame. This principle of equivalence was one of the foundational underpinnings for the development of the general theory of relativity.[11]

Though Sir Isaac Newton's most famous equation is , he actually wrote down a different form for his second law of motion that did not use differential calculus.

[edit]Newton's second law

Main article: Newton's laws of motion#Newton's second law

A modern statement of Newton's second law is a vector differential equation:[12]

where  is the momentum of the system, and  is the net (vector sum) force. In equilibrium, there is zero net force by definition, but (balanced) forces may be present nevertheless. In contrast, the second law states an unbalanced force acting on an object will result in the object's momentum changing over time.[10]

By the definition of momentum,

where m is the mass and  is the velocity.

In a system of constant mass, the use of the constant factor rule in differentiation allows the mass to move outside the derivative operator, and the equation becomes

.

By substituting the definition of acceleration, the algebraic version of Newton's second law is derived:

It is sometimes called the "second most famous formula in physics".[13] Newton never explicitly stated the formula in the reduced form above.

Newton's second law asserts the direct proportionality of acceleration to force and the inverse proportionality of acceleration to mass. Accelerations can be defined through kinematic measurements. However, while kinematics are well-described through reference frame analysis in advanced physics, there are still deep questions that remain as to what is the proper definition of mass. General relativity offers an equivalence between space-time and mass, but lacking a coherent theory of quantum gravity, it is unclear as to how or whether this connection is relevant on microscales. With some justification, Newton's second law can be taken as a quantitative definition of mass by writing the law as an equality; the relative units of force and mass then are fixed.

The use of Newton's second law as a definition of force has been disparaged in some of the more rigorous textbooks,[3][14] because it is essentially a mathematical truism. Notable physicists, philosophers and mathematicians who have sought a more explicit definition of the concept of force include Ernst Mach, Clifford Truesdell and Walter Noll.[15]

Newton's second law can be used to measure the strength of forces. For instance, knowledge of the masses of planets along with the accelerations of their orbits allows scientists to calculate the gravitational forces on planets.

[edit]Newton's third law

Main article: Newton's laws of motion#Newton's third law: law of reciprocal actions

Newton's third law is a result of applying symmetry to situations where forces can be attributed to the presence of different objects. For any two objects (call them 1 and 2), Newton's third law states that any force that is applied to object 1 due to the action of object 2 is automatically accompanied by a force applied to object 2 due to the action of object 1[16]

This law implies that forces always occur in action-and-reaction pairs.[10] If object 1 and object 2 are considered to be in the same system, then the net force on the system due to the interactions between objects 1 and 2 is zero since

This means that in a closed system of particles, there are no internal forces that are unbalanced. That is, action-and-reaction pairs of forces shared between any two objects in a closed system will not cause the center of mass of the system to accelerate. The constituent objects only accelerate with respect to each other, the system itself remains unaccelerated. Alternatively, if an external force acts on the system, then the center of mass will experience an acceleration proportional to the magnitude of the external force divided by the mass of the system.[3]

Combining Newton's second and third laws, it is possible to show that the linear momentum of a system is conserved. Using

and integrating with respect to time, the equation:

is obtained. For a system which includes objects 1 and 2,

which is the conservation of linear momentum.[17] Using the similar arguments, it is possible to generalizing this to a system of an arbitrary number of particles. This shows that exchanging momentum between constituent objects will not affect the net momentum of a system. In general, as long as all forces are due to the interaction of objects with mass, it is possible to define a system such that net momentum is never lost nor gained.

Types of Forces

There are nine types of forces you can apply to simulations, each described in this section. Each force is represented by its own control object, which can be selected, transformed, rotated, and scaled like any other object in the scene. For example, you can animate the rotation of a fan’s control object to create the effect of a classic oscillating fan. Scaling a force’s control object changes its strength (amplitude) accordingly.

Attractor

Drag

Eddy

 Toric

Turbulence

Wind

Attractor (Magnet)

The attractor attracts or repels ICE particles, hair, or rigid bodies much like a magnet attracts/repels iron filings, depending on whether you specify a positive or negative value for the Amplitude (strength). Positive values repel objects from the attractor control object while negative values attract them to its center.

 Rigid bodies are attracted to the attractor’s center when they’re inside the sphere.

You can set the attractor’s range of influence so that the magnetic field will have an effect only on objects that are within the number of Softimage units that you specify.

You can also set the decay of the attractor to have maximum force at the center and minimum at the edges, or the reverse (with negative values) with minimum force at the center and maximum at the edges.

Drag

The drag force opposes the movement of ICE particles, rigid bodies, and hair as if they were in a medium, such as fluid. This give a more direct level of control when you want to slow down particles or hairs. For example, you could create the effect of hair moving under water using the drag force or create a slow-motion effect of particles as they are being emitted.

In the image below, the particles are slowed down by the drag force, as if they are moving through a thick fluid.

You can control the drag’s amplitude, which is the strength of the force. You can also set the flow type to be either Laminar (a smooth and regular flow) or Turbulent (an irregular, more chaotic flow).

The basic drag force formula uses the cross-sectional area of the simulated object (Assume Size option) as the scaling factor, but you can set the Radius which calculates the drag using an area value in Softimage units that you specify.

Eddy (Vacuum)

An eddy force simulates the effect of a vacuum or local turbulence on ICE particles, rigid bodies, hair, and cloth by creating a vortex force field inside a cylinder. Anything that is inside the cylinder is affected by the force.Rigid bodies are swirled around inside the eddy control object, then are flung out as they leave the control object.

You can control the eddy’s flow velocity, which is the speed of the force. As well, you can use the eddy’s flow viscosity to create a drag effect on the simulated objects.

To control the eddy’s area of influence, you can adjust the size of its radius and length of its cylinder.

The force is defined along the cylinder’s axis and in a radius. For the force going in a radial direction, negative values attract objects toward the cylinder axis, while positive values push objects away from it.

The eddy’s intensity falls off (decays) from the cylinder’s center to its outer edge (radius), and moves from the bottom to the top of the axis. You can adjust the falloff for both the radial and axial decay.

Fan

The fan creates a “local” effect of wind blowing through a cylinder so that everything inside the cylinder is affected. The fan’s wind direction follows the cylinder’s axis.

 Rigid bodies that are within the fan control object are pushed away from it.

You can control the fan’s velocity, which is its speed. As well, you can use the fan’s flow viscosity to create a drag effect on the simulated objects.

To control the fan’s area of influence, you can adjust the size of the radius and length of its cylinder.

The fan’s intensity falls off (decays) from the cylinder’s center to its outer edge (radius), and moves from the bottom to the top of the axis (its drop length). You can adjust the intensity’s falloff for both the radial (across its axis) and axial (along its length) decay.

Gravity

Gravity is the most common type of “force” that you will use, for obvious reasons. Gravity is actually an acceleration that is the same for all objects regardless of their mass: every object falls at the same rate (remember Galileo and Newton?). However, everything changes at the moment there is air resistance/friction or when the object collides with another because that’s where its mass, energy, and momentum play a major role.

 To have the correct gravitational behavior from the objects, the size of the objects in the scene must be taken into consideration. In Softimage, the default gravity is set to 98.1, which is earth’s gravity if you define 1 Softimage unit as 10 cm. This scale is used because most characters are modeled with a scale of 1 unit equalling 10 cm, and it is also the scale used for the default Softimage rigs and models.

However, if you define 1 Softimage unit as 1 meter, you would need to set the gravity to 9.81. Depending on the scale of objects in your scene, you may need to adjust this value (including a negative value) to get objects falling as they should.

Toric

The toric force is similar to an eddy except that it is in the shape of a torus (also known as a donut, which tastes better). It simulates the effect of a vacuum or local turbulence by creating a vortex force field inside the torus. Anything that is inside the torus is affected by the force.

This force is useful for making billowing effects in smoke simulations or having ICE particles or rigid bodies “sucked” through a tube to follow a path. If you want to do effects such as mushroom clouds or billowing smoke, use a drag force working in conjunction with this one.

You can keep the torus closed (360 degrees) or you can have it open. This can be useful for having particles travel through one or more open-ended toric forces as if they were being piped through a straw.

Rigid bodies get sucked into the torus and swirl along its main circumference. When they go outside of the toric control object, they get flung off into space.

You can control the size of the toric force by setting its main radius (essentially the size of the torus) and the cross-section, which is the thickness of the torus.

You can use the toric force’s flow viscosity to create a drag effect on the simulated objects.

The torus force has three different Flow Velocity components:

• The Around Axis is the strength of the force that pushes the simulated objects (spins them) around the cross-section the torus in a cyclical way.

• The Away From Axis strength attracts objects toward or repels them away from the main axis.

• The Around Torus strength moves objects along the main torus axis through the tube.

As well, you can set the decay (falloff) of the amplitude as objects are farther away from the main axis.

Turbulence

Turbulence creates allover random noise patterns on simulated objects. This could be useful for creating starfields, for example, or foggy or smoky atmospheric effects when used with a sprite shader.

If you’re using ICE particles, you can use the Turbulence node or Turbulize compounds to deform an object by perturbing its points, such as for creating ocean wave-like effects on a grid.

Turbulence generates a random noise among the rigid bodies as the simulation starts. In this case, the turbulence is applied only along the X axis.

You can set the amplitude (strength) of the turbulence using either positive or negative values.

You can choose to use either Perlin or Simplex noise:

• Perlin noise has spatial coherence, meaning that several different points in roughly the same location in space tend to have similar noise added to them. It interpolates between the random values. Perlin noise can help make objects more natural-looking by imitating the controlled random appearance of elements found in nature; that is, there is structure to the noise while still appearing fairly random.

• Simplex noise is similar to Perlin noise, but is less computationally complex. This is because it divides the space into equilateral triangles to interpolate between, which reduces the number of data points. This makes Simplex noise useful for producing noise over large spatial areas.

Simplex noise has a well-defined and continuous gradient everywhere that can be computed fairly quickly, and has no noticeable directional artifacts.

The Frequency parameters determine the number of times the noise pattern is repeated on each axis that you choose. You can also set the noise frequency over time (in frames), letting you speed up or slow down the whole effect.

You can also add a fractal-type of complexity to the noise which increases the level of detail.

Vortex

The vortex simulates a spiralling, swirling movement on ICE particles, rigid bodies, or hair.

Rigid bodies swirl around the axis inside the vortex control object. With Local selected, the rigid bodies are affected only when they’re within the sphere. When they go outside of the control object, they are flung off into space.

You can control the vortex amplitude, which is the strength of the force, including a radial component. You can set the vortex’s range of influence so that the vortex will have an effect only on objects that are within the number of Softimage units that you specify.

You can also set the decay of the vortex to have maximum force at the center and minimum at the edges, or the reverse (with negative values) with minimum force at the center and maximum at the edges.

Wind

The wind force creates the effect of wind blowing on the simulated objects. You can control the wind’s velocity (speed) and its flow viscosity, which creates a drag effect on the simulated objects.

If there are no other forces at work on an ICE particle simulation except wind, particles will eventually reach the speed of the wind’s velocity setting which, in some cases, can actually slow down the particle velocity at emission. This is because particles have an initial velocity of their own when they’re emitted

Forms of Energy

Mechanical energy

Mechanical energy puts something in motion. It moves cars and lifts elevators. A machine uses mechanical energy to do work. The mechanical energy of a system is the sum of its kinetic and potential energy. Levers, which need a fulcrum to operate, are the simplest type of machine. Wheels, pulleys and inclined planes are the basic elements of most machines.

Chemical energy

Chemical energy is the energy stored in molecules and chemical compounds, and is found in food, wood, coal, petroleum and other fuels. When the chemical bonds are broken, either by combustion or other chemical reactions, the stored chemical energy is released in the form of heat or light. For example, muscle cells contain glycogen. When the muscle does work the glycogen is broken down into glucose. When the chemical energy in the glucose is transferred to the muscle fibers some of the energy goes into the surroundings as heat.

Electrical energy

Electrical energy is produced when unbalanced forces between electrons and protons in atoms create moving electrons called electric currents. For example, when we spin a copper wire through the poles of a magnet we induce the motion of electrons in the wire and produce electricity. Electricity can be used to perform work such as lighting a bulb, heating a cooking element on a stove or powering a motor. Note that electricity is a "secondary" source of energy. That means other sources of energy are needed to produce electricity.

Radiant energy

Radiant energy is carried by waves. Changes in the internal energy of particles cause the atoms to emit energy in the form of electromagnetic radiation which includes visible light, ultraviolet (UV) radiation, infrared (IR) radiation, microwaves, radio waves, gamma rays, and X-rays.

Electromagnetic radiation from the sun, particularly light, is of utmost importance in environmental systems because biogeochemical cycles and virtually all other processes on earth are driven by them.

Thermal energy

Thermal energy or heat energy is related to the motion or vibration of molecules in a substance. When a thermal system changes, heat flows in or out of the system. Heat energy flows from hot bodies to cold ones. Heat flow, like work, is an energy transfer. When heat flows into a substance it may increase the kinetic energy of the particles and thus elevate its temperature. Heat flow may also change the arrangement of the particles making up a substance by increasing their potential energy. This is what happens to water when it reaches a temperature of 100ºC. The molecules of water move further away from each other, thereby changing the state of the water from a liquid to a gas. During the phase transition the temperature of the water does not change.

Nuclear energy

Nuclear energy is energy that comes from the binding of the protons and neutrons that make up the nucleus of the atoms. It can be released from atoms in two different ways: nuclear fusion or nuclear fission. In nuclear fusion, energy is released when atoms are combined or fused together. This is how the sun produces energy. In nuclear fission, energy is released when atoms are split apart. Nuclear fission is used in nuclear power plants to produce electricity. Uranium 235 is the fuel used in most nuclear power plants because it undergoes a chain reaction extremely rapidly, resulting in the fission of trillions of atoms within a fraction of a second

The source of energy for many processes occurring on the earth's surface comes from the sun. Radiating solar energy heats the earth unevenly, creating air movements in the atmosphere. Therefore, the sun drives the winds, ocean currents and the water cycle. Sunlight energy is used by plants to create chemical energy through a process called photosynthesis, and this supports the life and growth of plants. In addition, dead plant material decays, and over millions of years is converted into fossil fuels (oil, coal, etc.).

Today, we make use of various sources of energy found on earth to produce electricity. Using machines, we convert the energies of wind, biomass, fossil fuels, water, heat trapped in the earth (geothermal), nuclear and solar energy into usable electricity. The above sources of energy differ in amount, availability, time required for their formation and usefulness. For example, the energy released by one gram of uranium during nuclear fission is much larger than that produced during the combustion of an equal mass of coal.

An energy sink is anything that collects a significant quantity of energy that is either lost or not considered transferable in the system under study. Sources and sinks have to be included in an energy budget when accounting for the energy flowing into and out of a system.

Conservation of Energy

Examples of the transformation of different energy forms.

Though energy can be converted from one form to another, energy cannot be created or destroyed. This principle is called the "law of conservation of energy." For example, in a motorcycle, the chemical potential energy of the fuel changes to kinetic energy. In a radio, electricity is converted into kinetic energy and wave energy (sound).

Machines can be used to convert energy from one form to another. Though ideal machines conserve the mechanical energy of a system, some of the energy always turns into heat when using a machine. For example, heat generated by friction is hard to collect and transform into another form of energy. In this situation, heat energy is usually considered unusable or lost.

Animation: Fuel Cell Vehicle

Energy Units

1 British Thermal Unit = 1055 Joules.

In the International System of Units (SI), the unit of work or energy is the Joule (J). For very small amounts of energy, the erg (erg) is sometimes used. An erg is one ten millionth of a Joule:

1 Joule = 10,000,000 ergs</dd>

Power is the rate at which energy is used. The unit of power is the Watt (W), named after James Watt, who perfected the steam engine:

1 Watt = 1 Joule/second</dd>

Power is sometimes measured in horsepower (hp):

1 horsepower = 746 Watts</dd>

Electrical energy is generally expressed in kilowatt-hours (kWh):

1 kilowatt-hour = 3,600,000 Joules</dd>

It is important to realize that a kilowatt-hour is a unit of energy not power. For example, an iron rated at 2000 Watts would consume 2 x 3.6 106 J of energy in 1 hour.

Heat energy is often measured in calories. One calorie (cal) is defined as the heat required to raise the temperature of 1 gram of water from 14.5 to 15.5 ºC:

1 calorie = 4.189 Joules</dd>

An old, but still used unit of heat is the British Thermal Unit (BTU). It is defined as the heat energy required to raise the energy temperature of 1 pound of water from 63 to 64ºF

UNIT 1 FAMILY

Family is the collective body of persons who live in one house, and under one head or manager; a household, including parents, children, and servants, and, as the case may be, lodgers or boarders.

Family, culture, and community are essential foundations of child development. These three contexts teach children who they are as human beings, how they should relate to others, and what they can aspire to becoming as adults. These three settings are interrelated in their effects on children.

Family Structures

Families come in many forms, including two-parent families, single-parent families, blended families, adoptive families, foster families, extended families, and numerous other types. Many youngsters experience one or more changes in family structure (e.g., as a result of divorce, remarriage, or death of a parent) at some point during their childhood or adolescence. Individual family structures offer unique benefits and challenges for children, but ultimately the quality of family relationships exceeds family structure in developmental significance. Teachers can be inclusive of families by recognizing the existence of many structures and inviting families of all kinds to become involved at school.

Importance of family in our life

Family is very important part of our everyday life. It helps us in improving our personality. It also helps us in shaping our life. It teaches us the value of love, affection, care, truthfulness and self-confidence and provides us tools and suggestions which are necessary to get success in life.

Family is a place where you can be yourself. It is a place where you are accepted for what you are. This is where you are completely tension free and everyone is there to help you. Family encourages you when you are surrounded by problems. It helps you survive through tough times and bring joy and happiness into life.

Decency is very important in the communication of daily life. It helps us make strong relationship with others and make us come across as a very gentle, intelligent and likable person. Everyone loves to be in a company of such person. Family helps bring decency into our life which is necessary to lead a happy life.

One of the most important aims of our life is to build a successful and highly rewarding career. Our families help us in creating a strong future. It gives us valuable suggestion about different career prospective. It not only guides us in choosing the best but also financially helps us to cover the expenses of education. Thus it helps us in making a good future.

The importance of family is probably realized when one went to holiday or celebrate an occasion without family members. It was very hard to celebrate an occasion or went to holiday without being surrounded by family members. At that time probably we realize that how important they are to us. At that time, we came to know about the importance of our families.

Today, most people don't realize the importance of family. They prefer to spend most of their time with their friends. But when they are surrounded by problems, it was their family that helped them get rid of problems. At the time, when even our best friends refuse to help us, it was our family that came to help us. So it is very important for each and every individual to give importance to their families above anything else and enjoy spending time with family members

Family Relationship

Your family is the environment where you learned to use your faculties and understand and cope with the physical world. It is a time when you didn't bother with trivial things, such as the family relationship, because you knew you are the kingpin of your family. It is the place, where you learned how family relationships work, by observing your parents, grandparents, your siblings and rest of the family members deal with each other. You must have enjoyed meeting them on family vacations and family reunions and exchanging family reunion gifts with them.

With the passage of time, you matured and started taking note of other people on the fringe of your family and then of those, outside your family and how your family members interacted with them. It is this point in your life, when you learnt, what is meant by a healthy relationships and how to make a relationship last. You also noticed, how your family coped and adjusted with the ups and downs of life and time. Do you remember, whether your family exposed you to these difficult times or were you cocooned in the safety of your family totally, unaware of them.

Importance of  Identity

What you learned from your family becomes your value system and forms your perceptions and basis of actions. An individual is known by his or her actions. It is your family that gave you an identity. Whenever you move from one place to another, you carry your family history with you. Have you ever noticed that your opinions always confirmed to the values you acquired from your family or delved deep inside them to find the seeds of thoughts that lies at their bottom? Who planted these thoughts? What gives you courage, when you are riding the wave of fortune at its deepest trough with its crest hanging over your head like a sword.

Every individual, barring few unfortunates, are similar to the earth enveloped by its environment, which acts as a protective layer and keeps the empty space out. The earth is populated and fertile because of it. For an individual, the importance of family is incalculable

Family Processes

Parents influence children's development through the relationships they build with children, the activities in which they include children, and their manner of showing affection and disciplining children. Parents may affect children's development through their employment outside the home; for instance, some children of working parents care for themselves during after-school hours. Children influence their families, in turn, by virtue of their temperaments, interests, and abilities. Children also influence one another as siblings, but having a sibling is not vital to normal, healthy development.

Most families provide safe and nurturing environments for children. However, some families maltreat children, either by neglecting them or by subjecting them to physical, sexual, or emotional abuse. Such maltreatment can have negative long-term effects on children's development.

Effective partnerships between educators and families rest squarely on good communication. Teachers can use several methods of communication, and they can try to get parents actively involved in children's education and activities.

Life in the Community for Children and Families

In various societies across the globe, the society might differ but the fundamental structure of the family remains the same. Family is the fundamental unit in the entire social structure. Society is a web of relationships between individual members and also between individuals and social organizations and social institutions. The Definition of Family is given in various ways in various societies, but the crux is the same. Family Definition can be found in any book of Sociology, but it is much more than a mere definition in a book. It is the unit which binds one human being to another and forms a blood tie between two members within a family. Definition of Family mentions that a family is formed when a group of people live in a domestic environment.

A common ancestor, adoption and marriage are the basic source of a family. In a very intimate and close environment, a group of people share space with each other.Affinity, blood kinship and cohabitation are the three primary aspects which are reflected in the Definition of Family. A family performs an array of functions which includes both political functions as well as economical functions. These functions are extremely important as without these functions, a family cannot function in the way it is supposed to.

Reproduction is the primary function of any society, either socially or in a biological way, or both. The family serves as a great tool to locate children within a particular social environment. Enculturating and socializing children are two of the prime functions of a family, in regard to children. For children a family is a family of orientation and for adults and parents it is a family of procreation. The Definition of Family maintains that a family can be of three kinds, namely, matrifocal, consanguinal, and conjugal. A household has to be productive in order to provide sustenance to the members of the family. In recent times, families are formed even without children.

The family structure is usually build on the relationship between children and parents and between husband and wife, or may be both. In matrifocal families, a mother and her children are the primary members. The children are biologically born to the women. This type of family is usually found in societies where the mother are more capable of rearing their children or their husbands are often away from home. In a consanguinal family the members are usually the mother, the children and the mother's family members. The structure is reversed too, and in such families, inheritance plays a very important role. The inheritance determines who will be the head of the family, the husband or the wife. In a conjugal family, the family comprises one or more mothers and their respective children, or one or more husbands. The men exercise control on their children, in this type of family, or the family is generally mobile.

According to anthropologists, the unit of family forms the elementary economic unit. However, much of this function has changed with time. Politically too, a family has a very important role to perform.

Children and families are profoundly affected by their experiences in ethnic groups and cultural traditions. To a large extent, children's ethnicity affects children's values, actions, and styles of communicating. Boys and girls are socialized somewhat differently, depending on their ethnicity and the particular beliefs of their families. Children also are influenced by their community's character and by the incomes of their families. Educators can build on children's experiences in the community, and, very important, help economically disadvantaged children by providing support, resources, and acknowledgement of children's personal strengthens.

Terms used within the nuclear family:

Grandparent

Grandfather: a parent's father

Grandmother: a parent's mother

Grandson: a child's son

Granddaughter: a child's daughter

For collateral relatives, more classificatory terms come into play, terms that do not build on the terms used within the nuclear family:

Uncle: father's brother, mother's brother, father's sister's husband, mother's sister's husband

Aunt: father's sister, mother's sister, father's brother's wife, mother's brother's wife

Nephew: sister's son, brother's son, wife's brother's son, wife's sister's son, husband's brother's son, husband's sister's son

Niece: sister's daughter, brother's daughter, wife's brother's daughter, wife's sister's daughter, husband's brother's daughter, husband's sister's daughter

Complex or Joint Family               

Complex family is a generic term for any family structure involving more than two adults. The term can refer to any extended family or to a polygamy of any type. It is often used to refer to the group marriage form of polygamy.

A joint family (or extended family) can also be known as a complex family, parents and their children's families often live under a single roof. This type of family often includes multiple generations in the family. In India, the family is a patriarchal society, with the sons' families often staying in the same house.

In the joint family setup the workload is shared among the members, often unequally. The women are often housewives and cook for the entire family. The patriarch of the family (often the oldest male member) lays down the rules and arbitrates disputes. Other senior members of the household baby sit infants in case their mother is working. They are also responsible in teaching the younger children their mother tongue, manners and etiquette.

The house often has a large reception area and a common kitchen. Each family has their own bedroom. The members of the household also look after each other in case a member is ill.

Dysfunctional family

A dysfunctional family is a family, in which conflict, misbehavior, and often abuse on the part of individual members occur continually and regularly, leading other members to accommodate such actions. Children sometimes grow up in such families with the understanding that such an arrangement is normal. Dysfunctional families are primarily a result of co-dependent adults, and may also be affected by addictions, such as substance abuse (alcohol, drugs, etc.). Other origins include untreated mental.illness, and parents emulating or over-correcting their own dysfunctional parents. In some cases, a "child-like" parent will allow the dominant parent to abuse their children.

Relationships

An interpersonal relationship is an association between two or more people that may range from fleeting to enduring. This association may be based on limerence, love, solidarity, regular business interactions, or some other type of social commitment. Interpersonal relationships are formed in the context of social, cultural and other influences. The context can vary from family or kinship relations, friendship, marriage, relations with associates, work, clubs, neighborhoods, and places of worship. They may be regulated by law, custom, or mutual agreement, and are the basis of social groups and society as a whole.

A relationship is normally viewed as a connection between two individuals, such as a romantic or intimate relationship, or a parent–child relationship. Individuals can also have relationships with groups of people, such as the relation between a pastor and his congregation, an uncle and a family, or a mayor and a town. Finally, groups or even nations may have relations with each other, though this is a much broader domain than that covered under the topic of interpersonal relationships. See such articles as international relations for more information on associations between groups. Most scholarly work on relationships focuses on romantic partners in pairs or dyads. These intimate relationships are, however, only a small subset of interpersonal relationships. Interpersonal relationships can also include friendships, such as relationships involving individuals providing relational care to marginalized persons.

These relationships usually involve some level of interdependence. People in a relationship tend to influence each other, share their thoughts and feelings, and engage in activities together. Because of this interdependence, most things that change or impact one member of the relationship will have some level of impact on the other member.[1] The study of interpersonal relationships involves several branches of the social sciences, including such disciplines as sociology, psychology, anthropology, and social work. The scientific study of relationships is referred to as "Relationship Science" and distinguishes itself from anecdotal evidence or pseudo-experts by basing conclusions on data and objective analysis.

Types of relationships

Family · Marriage

Husband · Wife

Soulmate · Significant other

Siblings · Cousin

Domestic partnership

Widowhood

Boyfriend · Girlfriend

Cohabitation · Casual

Romantic friendship · Sexual partner

Friendship · Kinship

Monogamy · Same-sex relationship

Non-monogamy · Open marriage

Polyamory · Polyfidelity · Polygamy · Relationship anarchy

Mistress (lover) · Cicisbeo · Concubinage · Courtesan ·

Romantic relationship events

Bonding · Breaking up · Courtship · Dating · Divorce · Infidelity · Mating · Meet market  · Romance · Separation · Singles event  · Transgressing · Wedding

Feelings and emotions

Affinity · Attachment · Compersion · Intimacy · Jealousy · Limerence · Love · Passion · Platonic love · Psychology of sexual monogamy

Human practices

Bride price (Dower · Dowry) · Hypergamy · Infidelity · Sexuality

Relationship abuse

Child abuse · Elder abuse · Dating abuse · Infidelity

The natural development of a relationship follows five stages:

Acquaintance – Becoming acquainted depends on previous relationships, physical proximity, first impressions, and a variety of other factors. If two people begin to like each other, continued interactions may lead to the next stage, but acquaintance can continue indefinitely.

Buildup – During this stage, people begin to trust and care about each other. The need for intimacy, compatibility and such filtering agents as common background and goals will influence whether or not interaction continues.

Continuation – This stage follows a mutual commitment to a long-term friendship, romantic relationship, or marriage. It is generally a long, relative stable period. Nevertheless, continued growth and development will occur during this time. Mutual trust is important for sustaining the relationship.

Deterioration – Not all relationships deteriorate, but those that do tend to show signs of trouble. Boredom, resentment, and dissatisfaction may occur, and individuals may communicate less and avoid self-disclosure. Loss of trust and betrayals may take place as the downward spiral continues, eventually ending the relationship. (Alternately, the participants may find some way to resolve the problems and reestablish trust.)

Termination – The final stage marks the end of the relationship, either by death in the case of a healthy relationship, or by separation.

The Sociology of the family examines the family, as an institution and a unit of socialisation, through various sociological perspectives, particularly with regard to the relationship between the nuclear family and industrial capitalism, and the distinct gender roles and concepts of childhood which arose with it. The sociology of the family is a common component on introductory and pre-university academic curricula, as it is perhaps the most simple institution to which one may apply many fundamental sociological approaches.

Sociology of motherhood

In many cultures, especially in a traditional western one, a mother is usually the wife in a married couple. Her role in the family is celebrated on Mother's Day. Anna Reeves Jarvis was a woman who originally organized Mother's Work Day's protesting the lack of cleanliness and sanitation in the work place.[3][4] Anna died in 1905 and her daughter created a National Mother's Day to honor her mother.[3] Mothers frequently have a very important role in raising offspring and the title can be given to a non-biological mother that fills this role. This is common in stepmothers (female married to biological father). In most family structures the mother is both a biological parent and a primary caregiver.

In East Asian and Western traditional families, fathers were the heads of the families, which meant that his duties included providing financial support and making critical decisions, some of which must have been obeyed without question by the rest of the family members. "Some Asian American men are brought up under stringent gender role expectations such as a focus on group harmony and filial piety, carrying on their family name and conforming to the expectations of the parents."[5]

As with cultural concepts of family, the specifics of a mother's role vary according to cultural mores. In what some sociologists term the "bourgeois family", which arose out of typical 16th- and 17th-century European households and is often considered the "traditional Western" structure, the father's role has been somewhat limited. In this family model the father acts as the economic support and sometimes disciplinarian of the family, while the mother or other female relative oversees most of the childrearing. This structure is reflected, for example, in societies which legislate "maternity leave" but do not have corresponding "paternity leave."

Some often view mother's duties as raising and looking after their children every minute of everyday. Mothers are often criticized for not contributing to the family income but the lack of money that they contribute is due to the time that is put into raising the children, which allows no time for the mother to go out and work. If the family is really struggling and the mother does have to go out and seek work, she is also criticized. If the mother is out working, many people view her as abandoning her children and not giving them the best life. In this situation, it truly is a lose lose for the mother.

However, this limited role has increasingly been called into question. Both feminist and masculist authors have decried such predetermined roles as unjust. A nascent father's rights movement seeks to increase the legal standing of fathers in everything from child-custody cases to the institution of paid paternity leave or family leave.

Families are often influenced by the media portrayal of the way women should run their families. In the book Media and Middle Class Moms by Descartes, women are often influenced by the social norms and is often the reason as to why they believe staying home or working is the right thing to do while having a family.

Sociology of fatherhood

According to anthropologist Maurice Godelier, a critical novelty in human society, compared to humans' closest biological relatives (chimpanzees and bonobos , is the parental role assumed by the males, which were unaware of their "father" connection.

 In many cultures, especially traditional western, a father is usually the husband in a married couple. Many times fathers have a very important role in raising offspring and the title can be given to a non-biological father that fills this role. This is common in stepfathers (males married to biological mothers). In most family structures the father is both a biological parent and a primary caregiver.

In East Asian and Western traditional families, fathers are the heads of the families, which means that their duties include providing financial support and making critical decisions, some of which must be obeyed without question by the rest of the family members.

As with cultural concepts of family, the specifics of a father's role vary according to cultural folkways. In what some sociologists term the "bourgeois family", which arose out of typical 16th- and 17th-century European households and is considered by some[who?] the "traditional Western" structure, the father's role has been somewhat limited. In this family model the father acts as the economic support and sometimes disciplinarian of the family, while the mother or other female relative oversees most of the childrearing. This structure is enforced, for example, in societies which legislate "maternity leave" but do not have a corresponding "paternity leave."

However, this limited role has increasingly been called into question. Both feminist and masculist authors have decried such predetermined roles as unjust. A nascent father's rights movement seeks to increase the legal standing of fathers in everything from child-custody cases to the institution of paid paternity leave or family leave.

Family Similarities

Family resemblance

At some point or the other, we all have heard the phrase “You look so much like your Dad or Mom”. Normally, people from one family resemble each other. Children of the same parents look very similar to their parents. Sometimes children may look like their uncle and aunt too. This is due to genes.

Everybody has genetic blueprints that are received from both the parents. Due to this reason only, when twins are born, they often look a like. In our family twin brothers or sisters may be exactly alike.

If you compare the pictures of three generations from a family, you can easily trace the facial resemblance.

Family resemblance stands for the notion that members of a category (e.g., all dogs, or all games) resemble each other.

In general, family resemblance relies on some number of features shared by any group of category members, even though these features may not be shared by all members of the category.

Therefore, the basis for family resemblance may shift from one subset of the category to another

Familial resemblance arises when family members are more similar than unrelated pairs of individuals, and may be estimated in terms of correlations or covariances among family members. Multifactorial heritability (or generalized heritability) quantifies the strength of the familial resemblance and represents the percentage of variance that is due to all additive familial effects including additive genetic and those of the familial environment. However, the traditional concept of heritability, which may be more appropriately called the genetic heritability, represents only the percentage of phenotypic variance due to additive genetic effects. Resolving the various sources of familial resemblance entails other issues. For example, there may be major gene effects that are largely or entirely nonadditive, temporal or developmental trends, and gene-gene (epistasis) and gene-environment interactions. The design of a family study determines which of these sources are resolvable. For example, in nuclear families consisting of parents and offspring, the genetic and familial environmental effects are not resolvable because these relatives share both genes and environments. However, extended pedigree and twin and adoption designs allow separation of the heritable effects and, possibly, more complex etiologies, including interactions. Various factors affect the estimation and interpretability of heritabilities, for example, assumptions regarding linearity and additivity, assortative mating, and the underlying distribution of the data. No normality of the data can lead to errors in hypothesis testing, although it yields reasonably unbiased estimates. Fortunately, these and other complications can be directly modeled in many of the sophisticated software packages available today in genetic epidemiology

TWINS

Twins originate from a variety of organic instances. Some newborns may be identical while some aren’t. In some scenarios, twins share the same sex and in others, they don’t. Nonetheless, despite sharing the same birth date and DNA, they are poles apart in terms of personality traits and preferences. This statement can be reinforced by the quote- ‘I may be a twin but I'm one of a kind’. In this piece, you will uncover the various kinds of twins present in this world.

Different Kinds Of Twins

Monozygotic Twins

When a single zygote fuses with a sperm and splits into two separate embryos, the final product of this fertilization is what we scientifically call monozygotic twins. They are consistently identical to the human eye, sharing the same physical features due to matching genetic information. Since they stem from the same zygote containing either a male (XY) or female (XX) sex chromosome, their genders can never differ. However, in a few out of the ordinary cases of genetic mutation, a male foetus loses the Y chromosome and develops as a female with a deterred growth of ovaries. One-third of all twins are reported to be monozygotic.

Dizygotic twins

This occurrence is set off by the release of more than one egg in an ovulation cycle. When two separate eggs are fertilized by two separate sperms, fraternal twins are nine months away from earth! Also known as dizygotic twins, separate placentas, chorions and amnions confirm their type in the womb. Around two-thirds of all the twins in this world are fraternal.

Conjoined Twins

Conjoined twins or Siamese twins are essentially monozygotic twins that are joined ‘in-utero’. This rare and heartbreaking phenomenon is elucidated by unfinished division of the fertilized ovum. The two individuals will be stuck to one another till death brings them apart. Unless they consider surgery, which carries cautioned risks. Connected at certain parts of the body, Conjoined twins usually share the same organs, limbs and tissues.

Polar Body Twins

Sometimes, the egg first splits. Later, each half collides with a sperm. These twins might be extremely alike in several ways including looks but their DNAs won’t be 100% compatible.

Mirror Image Twins

Coming from a single fertilized egg, mirror image twins develop reverse asymmetric features. This can be attributed by a delayed split of the fertilized egg, often surpassing a week. 25% of identical twins tend to be mirror image twins. One will be left-handed and the other, right handed. They may possess matching birthmarks on opposite sides of their bodies and suck opposite thumbs. The name springs from the fact that if face to face, they would be seeing exact mirror reflections of themselves!

Same Face, Different Birthday

What if a Labour begins at the peak hours of New Year’s Eve and the second twin is still on the way while the first one is already inhaling monoxides? The clock strikes twelve and Oopsie! Forget their birthdays being one day apart. Picture this- Molly was born in 1983 and her twin sister Polly in 1984! In certain cases, preterm labor forces the delivery of one baby while the other one’s can be controlled.

Semi-Identical Twins

Identified in a pair of three-year old kids, these rare twins developed when two sperms fertilized one egg and later split. One twin was born a hermaphrodite while the other is anatomically male.

 

Heteropaternal Superfecundation

Very rarely but possibly a woman’s eggs can be fertilized by sperm from differing events of coitus. Suppose a woman engages in sexual intercourse with different partners, the twins could have separate biological fathers! This anomaly is defined as heteropaternal superfecundation.

Parasitic Twins

When conjoined twins develop asymmetrically and a tinier and less formed twin depends on the stronger, larger twin to survive, they are known as parasitic twins. A variation of this called ‘fetus in fetu’ occurs when an abnormally formed mass of cells swell inside the body of its monozygotic twin. At times, the other twin doesn’t get sufficient nutrition from the placenta.

Twins of Different Races

Heteropaternal superfecundation speaks of cases wherein fraternal (dizygotic) twins exhibit differing racial characteristics. In one case, the differentiation was propelled by a lab mix-up during an in-vitro procedure. Also, in UK, two bi-racial parents conceived fraternal twin girl twins; one was dark coloured and the other white. This is a "one in a million" occurrence, where twins acquire different genetic characteristics from their mixed races.