Interacting Populations
MS-LS2-4. Construct an argument supported by empirical evidence that changes to physical or biological components of an ecosystem affect populations. [Clarification Statement: Emphasis is on recognizing patterns in data and making warranted inferences about changes in populations, and on evaluating empirical evidence supporting arguments about changes to ecosystems.]
Learning Target
Learning Target
- Construct an argument supported by empirical evidence that changes to physical or biological components of an ecosystem affect populations.
Success Criteria
Success Criteria
Questions to Ponder
Questions to Ponder
- How are mice and lions similar to each other?
- What is a Food Chain?
- What is a Food Web?
"The Cirrrr-cle! The Circle of Life...."
"The Cirrrr-cle! The Circle of Life...."
Trophic Levels
Trophic Levels
Autotrophs vs. heterotrophs
Organisms get their food in one of two ways:
- Autotrophs (or producers) make their own food using light or chemical energy. Examples of autotrophs include plants, algae, and some bacteria.
- Heterotrophs (or consumers) get organic molecules by eating other organisms or their by-products. Animals, fungi, and many bacteria are heterotrophs. Specialized heterotrophs, called decomposers break down dead organic material and wastes.
- Each of the categories in the image to the right is called a trophic level, and it reflects how many steps separate an organism from the food chain's original energy source, such as light. However, in most ecosystems, energy flow is much more complicated than a chain. In this case, a food web can be used to represent these feeding interactions between trophic levels.
- In your science notebook create a food web using the organisms in the pyramid. Draw arrows to represent the flow of energy. (arrows show the direction of energy from producer to consumer)
Interacting Populations
Interacting Populations
Different species in a community can have a great affect on each other. In this activity you will find a graph that charts the birth rate and death rate of two populations that live on a small island.
- Complete the Interacting Populations Activity. Use the graph to answer the 5 questions.
- Read this article about the Aleutian Islands, Alaska
- Add the following terms to your two-column notes on Ecology*:
- limiting factor
- carrying capacity
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