Ecology is the study of the interactions between organisms and their environment, including the effects of climate, soil, water, and other organisms.

Terrestrial ecosystems are those that occur on land, while aquatic ecosystems are those that occur in water.

Adaptation is the process by which organisms change over time in order to better survive in their environment.

Biogeography is the study of the distribution and abundance of organisms across the Earth.

Community ecology is the study of the interactions between organisms within a community, including competition, predation, and mutualism.

Environmental science is the study of the interactions between organisms and their physical environment, including the effects of climate, soil, water, and pollution.

Photosynthesis is the process by which plants use sunlight to convert carbon dioxide and water into glucose, a form of energy that can be used by the plant.

Decomposition is the process by which organisms break down organic matter into simpler substances, such as carbon dioxide, water, and nutrients.

Cellular respiration is the process by which organisms release energy from glucose, a form of energy that can be used by the organism.

Methanogenesis is the process by which organisms convert organic matter into methane, a greenhouse gas.

Fermentation is the process by which organisms convert organic matter into ethanol, a type of alcohol.

Fermentation is the process by which organisms convert organic matter into lactic acid, a type of acid.

Hydrogenogenesis is the process by which organisms convert organic matter into hydrogen gas, a type of fuel.

Sulfidogenesis is the process by which organisms convert organic matter into sulfur compounds, such as hydrogen sulfide.

Nitrogen fixation is the process by which organisms convert organic matter into nitrogen compounds, such as ammonia and nitrate.