วันอาทิตย์ที่ 22 กันยายน พ.ศ. 2556

foodchains

Food chains
A food chain shows the different organisms that live in a habitat, and what eats what.
Producers and consumers
A food chain always starts with a producer, which is an organism that makes food. This is usually a green plant, because plants can make their own food by photosynthesis.
A food chain ends with a consumer, which is an animal that eats a plant or another animal. Here is an example of a simple food chain:
grass  cow  human
Take care - the arrow points to the organism that is doing the eating. If you get the arrows the wrong way round, instead of showing that humans eat cows, you are showing that cows eat humans, and that grass eats cows.
Other words in a food chain

There are several words used to describe the organisms in a food chain. Study this food chain:
The plant is the producer and the animals are consumers.
Notice that the first consumer in the chain is also called the primary consumer, the next one is the secondary consumer and the one after that is the tertiary consumer.
A consumer that eats plants is called a herbivore, and a consumer that eats other animals is called a carnivore. An omnivore is an animal that eats both plants and animals.
Grass
Grasshopper
Frog
Hawk
grass

A grasshopper

a frog

a hawk
Producer

Consumer

Consumer

Consumer


Primary consumer

Secondary consumer

Tertiary consumer


Herbivore

Carnivore

Carnivore
Predators and prey
A predator is an animal that eats other animals, and the prey is the animal that gets eaten by the predator. In the food chain above:
·         the frog is a predator and the grasshopper is its prey.
·         the hawk is a predator and the frog is its prey.

Food chains - Test


1.What are the products of photosynthesis?
2.What colour is chlorophyll?
3.Where does photosynthesis take place?

4.A green plant is usually a:
5.What does a food chain always start with?
6.Which is the secondary consumer in this food chain:
grass -> grasshopper -> frog -> hawk
7.What does an omnivore eat?




ไม่มีความคิดเห็น:

แสดงความคิดเห็น