Food Chains Food Webs and the Flow of
Food Chains, Food Webs, and the Flow of Energy in Nature
Nature needs all kinds of creatures • If suddenly there were only animals, and no plants in the world, the plant eating animals would die for lack of food. Then, animals that eat plant eaters would die because they had no food.
How does nature stay in balance? • Three groups of creatures form a circular chain that goes round and round: – Producers – Consumers – Decomposers
Producers • Plants that make their own food. • The beginning, or bottom, of every food chain and web. • They use the sun’s energy, and chemicals from the soil, water, and air to make food.
Consumers • The animals that eat the producers. • They get their energy from what they eat. • Consumers eat living things. • Primary Consumers: eat plants • Secondary Consumers: eat animals that eat plants.
Decomposers • Bacteria and fungi that turn dead matter into material that can be used by producers, so the cycle can continue.
The Food Chain Pyramid • Most of an animal’s energy that it gets from eating is used by that animal, and only a small part of it can get passed on to the next “eater”. • So, a primary consumer needs many producers to sustain it. • A secondary consumer needs many primary consumers to keep it alive.
Food Webs and Interdependence • Living things rely on one another to live. • Most creatures are part of many food chains. • Multiple food chains working together are called food webs.
Balance • When something happens to one part of the food chain, the whole food web is affected. • Two examples: Wolf Island, and Sea Otter Inlet. • Many things affect producers: weather, building, pesticides, pollution, harvesting • Many things affect primary consumers: pollution, building, hunting, loss of producers • Many things affect secondary consumers: pollution, building, hunting, loss of producers and primary consumers.
Food Webs are very complex • Loss of one species can impact many.
What could cause there to be less deer for this lion to eat? 1. Grass dies due to fire, building, disease, flood. Therefor, less food for the deer, less deer. 2. Deer die due to disease, building, flood 3. Another secondary consumer arrives and eats deer 4. The lion’s enemy leaves, so there are more lions to share the same number of deer
What affect would over hunting of pine martins have on this food web?
Current problems…maybe you can become the biologist to solve them. • Many bats are dying of White Nose disease. • Many honey bees are dying from pesticides (we think, but don’t know for sure, that pesticides are killing them).
The good news is that sometimes nature’s balance can be restored.
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