AP Environmental Science: Ecosystems

Objective

• Explain how resource availability influences species interactions.
• Discuss predator-prey relationships, symbiosis, competition, and resource partitioning.

Key Concepts

Ecosystem Basics

1. Individual

   • A single organism (e.g., one elk).

2. Population

   • A group of organisms of the same species (e.g., an elk herd).

3. Community

   • All living organisms in a given area (e.g., trees, beavers, bacteria).

4. Ecosystem

   • Interaction of living (biotic) and non-living (abiotic) components (e.g., rocks, soil, water).

5. Biome

   • Large area with a similar climate affecting the types of plants and animals (e.g., tropical rainforest).

Species Interactions

Types of Interactions

1. Competition

   • Lose-lose situation; organisms compete for shared resources, limiting population sizes.

2. Predation

   • Positive for predator, negative for prey (e.g., carnivores & herbivores).
   • Herbivory: Animals eating plants is a form of predation.
   • True Predators: Carnivores that kill and eat other animals.
   • Parasites: Extract energy without killing hosts (e.g., sea lamprey).
   • Parasitoids: Lay eggs inside hosts; larvae kill hosts (e.g., parasitic wasps).

3. Mutualism

   • Beneficial for both species (e.g., coral reefs with algae).
   • Lichen: Close relationship between fungi and algae, functioning as one organism.

4. Commensalism

   • One species benefits, the other is unaffected (e.g., birds nesting in trees).

Symbiosis

• Long-term interaction between species.
• Can be mutualistic, commensalist, or parasitic.

Resource Partitioning

• Reduces competition by utilizing resources differently.

Types

1. Temporal Partitioning

   • Different times of resource use (e.g., wolves and coyotes hunting at different times).

2. Spatial Partitioning

   • Different areas of resource use (e.g., roots occupying different soil depths).

3. Morphological Partitioning

   • Different body features for utilizing resources (e.g., jaw size differences in ferrets and ermines).

Practice FRQ

• Identify two competing organisms in a food web and describe how resource partitioning could reduce competition.

Conclusion

• Remember to "think like a mountain, write like a scholar."

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