Understand that organisms interact in a variety of ways within a community.

• Describe differences among predation, mutualism, competition, parasitism, and commensalism.
• Explain the difference between niche and habitat.
• Describe an organism's niche, habitat, and community.

Recognize the abiotic and biotic features that are typical of the major biomes of the world.

• List typical abiotic and biotic characteristics of different biomes.
• Explain why some plants and animals are found only in certain parts of the world.
• Describe the effect of temperature and rainfall to the kind of biome that develops.

Understand the concept of succession.

• Explain the concept of a climax community.
• Describe the effect humans have had on natural climax ecosystems.
• Explain why a vacant lot becomes a tangle of plants.

Appreciate that humans alter and interfere with natural ecological processes.

• Describe the impact of introduced species, predator control, and habitat destruction on natural communities.
• Explain why persistent organic chemicals reach higher levels in carnivores than in herbivores.
• Relate extinctions to human activities.