Energy in an Ecosystem

Energy Flow in an Ecosystem

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Energy Roles within an Ecosystem

Autotrophs

• Photosynthetic organisms

• Make their own food

• Also known as producers

• They provide a source of energy for almost all other organisms

Heterotrophs

• Must get food by eating other organisms, also known as consumers

• Herbivores

• Carnivores

• Omnivores

Herbivores

• Eat plants

• The "primary consumer" level of a food chain/food web

Carnivores - Predators

• Carnivores eat the flesh of other animals

• A predator is a type of carnivore that hunts and kills its prey

Carnivore - Scavenger

• Eat other animals that have previously been killed

• Note: predators can sometimes scavenge and scavengers can sometimes hunt

Omnivore

• Eat both plants and animals

• In a food web, omnivores can be in multiple trophic roles (primary consumer, secondary/tertiary consumer)

Decomposers

• Consume the waste and dead bodies of all organisms in an ecosystem

• The recycled materials can be reused by the producers

• DO NOT RECYCLE ENERGY

Multiple Choice

Which organisms are chiefly responsible for the recycling or dead matter?

• parasites

• viruses

• decomposers

• producers

Multiple Choice

In a natural community in New York State, the producer organisms might include

• bacteria, fungi, and viruses

• deer, rabbits, and squirrels

• grasses, maple trees, and weeds

• trout, peas, and earthworms

Multiple Choice

A consumer-producer relationship is best illustrated by

• foxes eating mice

• leaves growing on trees

• rabbits eating clover

• fleas living on a cat

Open Ended

Food chain:

rosebush > aphid > beetle > spider > toad > snake

If all of the aphids were killed off due to the spraying of pesticides, what would happen to the number of toads this ecosystem could support?

Open Ended

Food chain:

rosebush > aphid > beetle > spider > toad > snake

Which organism in this food chain can transform light energy into chemical energy stored in molecular bonds?

Ecosystem Diagrams

• Food Chain

• Food Web

• Energy Pyramid

Food Chain

• Shows the relationship between prey and predator

• Arrows illustrate the flow of energy from one organism to another

• Shows "what eats what"

Food Web

• Shows more complex feeding relationships in an ecosystem

• Shows the many interconnected food chains within an ecosystem

Energy Pyramid

• Illustrates the transfer of energy through an ecosystem

• Each level of the energy pyramid shows the amount of energy that was obtained from the organisms below it.

• Only about 10% of the energy in a trophic level will be passed on to the next level

Multiple Choice

Which sequence illustrates a generalized food chain in a natural community?

• autotroph > herbivore > carnivore

• autotroph > herbivore > autotroph

• heterotroph > herbivore > carnivore

• consumer > autotroph > carnivore

Multiple Choice

Decomposition and decay of organic matter are accomplished by the action of

• green plants

• viruses and algae

• bacteria and fungi

• scavengers