Science 10 Name: _________________

Chapter 2.1 Date: __________________

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Definition

OmnivoresPrimary ConsumersSecondary ConsumersTertiary ConsumersTrophic LevelTop CarnivoresHerbivoresCarnivoresDetritovores

Energy Flow Models:

Scientists use different models to help them understand how energy moves through an ecosystem. Sometimes these energy movements include energy losses. There are three main models:

1. Food Chains2. Food Webs3. Food Pyramids

Food Chains:

Each step in a food chain is called a trophic level. These trophic levels can show the feeding and niche relationships between organisms.

1st Trophic Level: plants and phytoplankton (such as algae) are the producers = primary producers

2nd Trophic Level: animals like grasshoppers, zooplankton and cows that eat primary producers for their energy = primary consumers

3rd Trophic Level: animals like frogs and cats that get their energy from eating primary consumers = secondary consumers

4th Trophic Level: animals like hawks, eagles, cougars that get energy by eating secondary consumers = tertiary consumers

Chapter 2: Energy Flow Food Chains, Food Webs, Food Pyramids

Draw a food chain showing who occupies all the different trophic levels:

Producers, consumers, and decomposers are names that show us the energy flow relationships between organisms. They show us their niche or job in the ecosystem.

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Detritovores: consumers that obtain their energy and nutrients by eating the bodies of small dead animals, dead plants and animal wastes. They eat at ALL trophic levels, and can also be an energy source for some consumers. Example: earthworms and beetles

Herbivores: are primary consumers that eat plants: Example: grasshoppers, deer

Carnivores: are secondary consumers and higher that eat other consumers. Example: frogs, birds

Top Carnivores: are the highest level of consumer in the ecosystem. Usually in the tertiary sonsumer level. They eat secondary consumers or higher. Examples: hawks, sea otters, killer whales

Omnivores: are consumers that eat both plants and animals. They will be part of more than one food chain. Examples: rats, humans, bears

Food chains are a very simple way of looking at an ecosystem. They are TOO SIMPLE! Do you think that every animal only eats one thing? Choose one animal and brainstorm all the different things it eats:

To be more accurate, we use food webs instead of food chains. Food webs give us a better picture of the feeding relationships and interactions within an ecosystem. Choose an ecosystem with your group and construct a food web for it. Start with the plants and go up!

Food webs show ALL the feeding relationships in the ecosystem. Many animals can be part of more than one food chain. For example, a grouse can be a primary consumer when it eats seeds and fruit but when it eats insects or young birds it becomes a secondary or tertiary consumer.

Q. How many different relationship does the grouse have?____________________________

Q. What would happen to the butterfuly population if there was a sudden increase in grass?

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Q. What would be the effect of a big drop in population of marmots?

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Where does all the energy enter an ecosystem from? Who gets it?

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Who eats the plants? Do they eat a little or a lot? What do they get from eating plants?

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Food Pyramids:

Models that show the loss of energy from one trophic level to another.

Also called ecological pyramids There are different kinds of ecological pyramids that show different relationships

Q. Which part of the pyramid controls the amount of energy for the rest of the pyramid? __________________________________________________________________________

Q. If there are very few producers, can there be many different levels of consumers?

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Q. What biomes would you expect to have very few different levels of consumers? Which ones would have a lot?

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Q. Which level of a food pyramid would have the highest number of organisms? ______________