Living Organisms And Their Surroundings: science class six
Living Organism
There is a wide variety of things around us. Things around us can be classified into two groups.
(a) Living things: Plants, animals, humans etc. are living things.
(b) Non living things: Chair, fan, table, cars, rock etc are nonliving things.
All living things show certain common characteristic such as need food, growing, respiration, response to stimuli, reproduce, excreate body wastes, etc.
Organisms and the Surroundings Where They live
Apart from food and water every animal needs a certain type of environment or surrounding where it can live and flourish. Every plant and animal is fit to live in a certain type of surrounding.
Habitat and Adaptation
Living being live and survive only under a certain condition. The surrounding where the living being live is called habitat. Organisms depend on their habitat for their food, water, air, shelter and other needs.
The meaning of habitat is a home (dwelling place). Several kinds of plants and animals may share, i.e. live in the same habitat. Habitat is the part of the total; environment of the region.Types of Habitat
There are three main types of habitat in the biosphere.
(a) Terrestrial habitat or Land habitat
Land, Mountain, Forest, and Desert are called Terrestrial habitat or Land habitat.
Organisms that live on land are called as terrestrial organisms. For example: man, tiger, trees, etc. live on land, thus these are called terrestrial organisms.
(b) Aquatic habitat or water Habitat
Sea, lake, River, Pond, etc are called Aquatic habitat or water habitat.
Organisms that live and breed in water called aquatic organisms. For example, fish, whales, etc. are called aquatic organism.
(c) Aerial or arboreal habitat
Tropical forests are called aerial or arboreal habitat.
The organisms which use trees for their activities are known as arboreal organisms. For example, all brids such as eagle, swallow, monkey, etc. are called aerial or arboreal organisms.
Adaptation
Organisms develop certain quality or property to keep themselves live in their environment. This quality of organism is called Adaptation. Although this, adaptation is a continuous process and it takes thousands of years to develop certain features.
Thus, Adaptation can be defined as "the tendency of organism to develop certain features which improve the chances of its survival in the environment in which it lives". Different plants and animals are adapted to their surroundings in different ways.
Example
Camel and desert rat are adapted to live in deserts habitat.
Cactus is adapted to live in desert. The leaves in cactus are modified into thorns. This helps in prevention of water loss. The stem of cactus is modified into leaf like structures. These leaves like structure are spongy and hence retain water. Because of these properties they can live in the deserts where there is a great scarcity of water.
Coconut trees are found mainly at the costal areas as they are adapted to survive in coastal areas. So during the tide, when the water level of sea rises upto two to six metres, the tip of the coconut trees do not dip into such a high level of water.
As you have seen in these examples, living beings have certain type of properties and special structures, which help them to survive in a particular environment and surroundings. This special ability of survival of living beings is called adaptation. Adaptation is a long process of evolution. It takes thousands of years to develop a particular adaptation.
Different animals are adapted to their surroundings in different ways.
Components of Habitat
There are two types of components in a habitat. One is called Biotic Component and another is called Abiotic Component.
Biotic components
Biotic means live. Thus, all living things in a habitat comprise the biotic component. Example: plants and animals.
Abiotic components
Abiotic means non–living. Thus, all non living things in a habitat comprise the abiotic component. For example, rocks, soil, water, air, etc.
In the word "Abiotic" A is a negative prefix, which makes a word negative in sense. Thus, "Abiotic" means "Non–biotic" means non–living.
Everything whether it is biotic or abiotic is important for a habitat. They are dependent on each other. They get affected if one of them gets disturbed. This balance in the biotic and abiotic components of a habitat is called the ecological balance.
Living and Non–living
It is easy to know which object is living and which is non–living. For example, we know that objects, like a chair or a table in are non living. We also know that animals, like dog, cat, and rabbit are living things. Plants are also living things.
We know that dog, cat, rabbit, hen, cow, etc. are living because they can move. But, plants cannot move yet they are living. On the other hand, car, bus, motorcycle can move but they are non living things.
If we say that those objects are living which can grow and so animals and plants are living. So it is necessary to understand some common property of living beings so that you can decide easily, which is living being and which is non living being.
Characteristics of Living and Non–living
Some common properties of living being are given below.
All living things need food
All living things show growth
All living things respire
All living things respond to stimuli
All living organisms do excretion
All living things reproduce their own kind
All living things need food
You do many works, like reading, playing, singing etc. The energy to do these works come from food. Every year you grow taller. Food provides raw material for growth. Without food a living organism cannot survive.
All living beings need food. You may have seen an animal taking food but have you seen a plant taking food? Your answer would be no. You can recall that green plants make their own food. The process of making of food in green plant is called photosynthesis.
Photosynthesis occurs in the presence of sunlight. You can see it with the activity given here.
Plants kept in dark place wilts because it could not make food in the absence of sunlight. Food gives organisms the energy needed for growth.
All living things show growth
Showing growth is one of the most important characteristics of living beings.
All living things respire
We inhale and exhale air through our nostril. In the course of inhaling the air moves from outside to inside of the body. When, we breathe in air moves from outside to inside in the body. This is called inspiration. When, we breathe out the air moves from the inside to outside the body. This is called expiration. Breathing is a part of a process called respiration.
In respiration, we breathe in oxygen of the air and we breathe out the carbon dioxide produced in this process. You can observe taking breathing in and breathing out.
All animals, like cows, buffaloes, dogs or cats respire, which is similar to the process in humans. Observe any of these animals while they are taking rest, and notice the movement of their abdomen. You will see this is similar to the process in humans. The movement of their abdomen indicates that they are breathing.
Respiration is necessary for all living organisms. Body finally gets energy from the food it takes, through the process of respiration.
There are certain animals which use different mechanisms to take in and out the air for the respiration. For example fish, which live in water, uses its gills for breathing. Gills can absorb oxygen from the air dissolved in water.
Similar to animals; plants also respire. The process of respiration takes place through leaves of plants
Leaves take in air through tiny pores, called STOMATA in them and use the oxygen. They give out carbon-dioxide to the air.
All living things respond to stimuli
What happens when you suddenly touch a hot tawa? You pull your hand away from the tawa. Whenever you go from dark room to a brightly lit place, your eyes feel some problem. For a moment you may not be able to see clearly. Your eye takes some time to adjust in brighter place. Whenever you hear about your favourite food, your mouth may start salivating.
These things happen due to stimulation of your sense organs. Almost all of us respond immediately to such changes. The process or phenomenon of this type of response is called stimulation.
All animals respond to stimuli the way man does. You can watch the alertness of a dog when it sees a piece of meat. Whenever you move towards a bird, it flies away.
Plants also respond to stimuli. Do you know that lotus blooms only during day time and shut its petals after the sun sets? Face of sunflower moves along the direction of sun. There is a plant named mimosa, which is popularly known as ?touch me not?. You must have heard about it. Whenever you touch it, its leaves close. These things happen due to the response towards stimuli.
All living things respond to changes around them.
All living organisms do excretion
The process of getting rid of wastes materials by the living organisms is known as excretion. Removal of waste is important because they are very harmful for the body. Major portion of waste gets remove through urine. Some waste is remove through faeces, sweat, spitting etc
Excretion happens in plants also. Some plants remove waste products as secretions. Excretion is another characteristic common to all living things
All living things reproduce their own kind
Reproduction is one of the most important characteristic of living things. Humans produce babies, a bird produces an egg, which hatches into a chick.
Plants also produce their own kind. During eating a fruit like mango, guava, orange etc you must have seen its seed. Seeds germinate to produce a plant.
Reproduction is necessary to continue the lineage of a living being.
Above mentioned characteristics are the common for all living organisms.
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