Form 2, Chap 04: Interdependence Among Living Organisms and the Environment (3)

Chapter4.3 Food Webs

Producers, consumers and decomposers

Producers Producers are all green plants that are able to make their own food through photosynthesis

Consumers Consumers are animals that eat plants or other animals to obtain energy and materials they need

Decomposers Decomposers are organisms that decompose the materials in the dead plants and animals into simple substances

1© Amazing Tunas Enterprise (001573407-U)TRG – Science Form 2

Chapter 4 : Interdependence Among Living Organisms and the Environment


Food chains

An example of food chain are show below:

producer secondary consumer

tertiary consumerprimary consumer

2

A food chain describes a single pathway that energy in food may passed from plants (producers) to animals (consumers)

© Amazing Tunas Enterprise (001573407-U)TRG – Science Form 2



Food webs

An example of food web are show below:

producer

primaryconsumer

secondaryconsumer

tertiaryconsumer

3

A food web is formed by two or more interconnection food chains




Pyramid of numbers

Eagle(tertiary consumer)

Small bird(secondary consumer)

Grasshopper(primer consumer)

Grass(producer)

4

A pyramid of numbers shows the number of organisms at each trophic level




The number of organisms decrease

The size of organisms decrease

More energy is lost




The flow of energy in a food chain

producer secondary consumer

tertiary consumerprimary consumer

energy lost energy lost

energy lost

6

The flow of energy in a food chain starts from the producer and moves to the consumers



The Sun is the main source of energy for all living organisms The number of producers is the most and forms the base of the pyramid

The flow of energy in a food web and in a pyramid of numbers is the same as in a food chain

Not all the energy in a producer will transferred to consumers

Some energy is lost as heat when the organism carries out its life process such as growth, reproduction, respiration and excretion

Q.R.4.3 Quick Refresh



Documents

Form 2, Chap 04: Interdependence Among Living Organisms and the Environment (3)