Ecosystems and Interactions

Study Notes

Ecosystems are made up of living (biotic) and nonliving (abiotic) parts.
Abiotic factors like water, carbon dioxide, oxygen, and nitrogen cycle through an ecosystem.
Biotic factors include producers, consumers, and decomposers.
Producers are organisms that make their own food using sunlight, like plants.
Consumers get energy by eating other organisms.
Decomposers break down dead organisms and waste, recycling nutrients back into the ecosystem.
Food chains and webs show how matter and energy flow through an ecosystem.
Energy pyramids show that the amount of available energy decreases at each level of the food chain.
Predators are consumers that hunt and kill other animals for food.
Prey are the animals that are hunted and killed by predators.

Mutualism: When both organisms benefit from an interaction.
Commensalism: When one organism benefits, and the other is neither harmed nor helped.
Parasitism: When one organism benefits at the expense of another.
Competition: When organisms vie for the same limited resources, like food, water, or shelter.

Photosynthesis: Plants use sunlight to convert carbon dioxide and water into sugars and oxygen.
Respiration: Organisms use oxygen to break down sugars and release energy, producing carbon dioxide as a waste product.

Nitrogen-fixing bacteria convert atmospheric nitrogen into a form that plants can use.
Decomposers release nitrogen back into the soil.

A diverse ecosystem is more resilient to change and better able to adapt to environmental challenges.
Loss of biodiversity can have negative consequences for the entire ecosystem.