Interdependece among living organisms and the environment

8/7/2019 Interdependece among living organisms and the environment

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1. Interdependence among living organisms

2. Interaction between living organisms

3. Food webs

4. Photosynthesis

5. Conservation and preservation of organisms

6. Role of human beings in maintaining the balance of nature


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Species

a group of similar organisms with common

characteristics

species can interbreed to produce fertileoffspring

Population

a group of organisms of the same species

living in the same habitat. For example, a

population of zebras.


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Community

different populations of organisms living together in

the same habitat.for example, a community in the savannah consists

of populations of zebras, giraffes and bisons.

Ecosystem

the various communities that interact with one

another and with the non-living environment


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In an ecosystem, various organisms live

together and are interdependent on one

another for their survival.

Examples:(a) plants make their own food by

photosynthesis. Plants are dependent on

abiotic factors such as sunlight and water.

(b) animals like deer depend on plants forfood


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(c) Other animals like tigers depend on deer for food

(d) Organisms depend on one another for food,

shelter and protection.(e) Microorganisms like bacteria and fungi are

decomposers. They decompose dead organisms.

Decomposition releases minerals into the soil which

become nutrients for plants. The interdependence among living organisms and

the environment creates a balanced ecosystem


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A balanced ecosystem is an ecosystem

(a) That is stable

(b) Does not change very much over a period of time

(c) In which there is a continuous supply of basic

needs like oxygen, food, shelter and breeding

partners.


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Organisms interact in many ways in an

ecosystem to obtain food, shelter and

protection

Competitionorganisms compete with each other for the

same basic needs like food, water, shelter

and mates. Competition becomes intense

when basic needs become limited


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(a) intraspecific competition; competition between

organisms of the same species. For example, a

Bryophyllum leaf with new seedlings growing on theparent leaf

(b) Interspecific competition; competition between

organisms of different species. For example, an owl

and a snake compete for rats.


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Symbiosis is the close relationship between

two organisms of different species which live

together and interact with each other. There

are 3 types of symbiosis: commensalism,mutualism and parasitism


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A relationship in which one organism the

commensal benefits while the other organism

the host does not receive any benefit or

harm. A remora fish, often found attached under a

shark, gets free transport and free left by

the shark without harming the shark.


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A relationship between two different species

of organisms in which both organisms benefit

Lichen is made up of an alga and a fungus.

The green alga produces food and the fungusprovides shelter.


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A relationship in which one organism benefits

parasite while the other the host is harmed.

Ticks,fleas and lice parasites live on the skin

of mammals hosts and suck the blood of thehost

Round worms and tapeworms live inside the

intestines of human hosts and obtain food

and shelter from the host


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The predator kills and eats smaller animals

called the prey

Predators have long canine teeth, sharp

vision, sharp claws and teeth to hold and killprey. Predators are carnivores.

Prey relies on speed or camouflage to avoid

being caught by predators. Prey can be

either carnivores, omnivores or herbivores Examples are;

(a) Owl and rat

(b) Snake and chicken

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Interdependece among living organisms and the environment