TROPHIC LEVELS, FOOD CHAINS AND FOOD WEBS UNIT 5 Ecosystems TROPHIC LEVELS, FOOD CHAINS AND FOOD WEBS Natural Science 2. Secondary Education 1

UNIT 5 Producers Producers are autotrophic organisms that create organic matter from inorganic matter: hence the name “producers.” Tulips Ash tree Natural Science 2. Secondary Education 2

UNIT 5 Primary consumers Primary consumers are animals that feed on autotrophic organisms like algae and plants. Herbivores are primary consumers. Rabbit Horse Natural Science 2. Secondary Education 3

UNIT 5 Secondary consumers Secondary consumers feed on primary consumers. Carnivores are secondary consumers. Penguins Natural Science 2. Secondary Education 4

UNIT 5 Tertiary consumers Tertiary consumers feed on secondary consumers. Birds of prey and wolves are examples of tertiary consumers. Wolves Natural Science 2. Secondary Education 5

Other types of consumers UNIT 5 Other types of consumers Omnivores are consumers with a varied diet: they can be both herbivores and carnivores. Examples are human beings, bears and ants. They can be classified in different trophic levels in a single ecosystem. Bear Natural Science 2. Secondary Education 6

Other types of consumers UNIT 5 Other types of consumers Detritivores are consumers that feed on decomposing organic matter or excrement. Examples are earthworms, woodlice and some beetles. Woodlouse Earthworm Natural Science 2. Secondary Education 7

Decomposers They are heterotrophic organisms which feed on the remains of the other trophic levels. They transform organic matter in inorganic matter. They are bacteria and fungi.

UNIT 5 Let’s make a food chain To make a food chain, we draw the organisms that form part of an ecosystem. Then we use arrows to represent the feeding relationship between them. The tip of the arrow points to the organism that eats, and the end of the arrow indicates the organism that is eaten. Great tit Strawberry tree Common kestrel Grasshopper is eaten by is eaten by is eaten by Natural Science 2. Secondary Education

UNIT 5 Let’s make a food web Food webs are made in the same way as food chains, but they show multiple feeding relationships within an ecosystem. In other words, they represent how different food chains are interconnected. Natural Science 2. Secondary Education