Ecosystems can be classified as terrestrial or aquatic, with aquatic further divided into marine and freshwater. Land ecosystems are often categorized into biomes, such as tropical forests or …

This unit explores the Earth as a system with interdependent components, processes, and relationships. Learn about ecosystems, terrestrial and aquatic biomes, natural climate change, …

Apply your understanding of ecosystems and biomes in this set of free practice questions aligned to AP standards

Key points An ecosystem consists of a community of organisms together with their physical environment. Ecosystems can be of different sizes and can be marine, aquatic, or terrestrial. …

Review your understanding of the taiga, tropical rainforest, temperate forest, shrubland, grassland, savanna, desert, and tundra biomes in this free article aligned to AP standards.

Community structure & diversity Learn Ecosystems and ecological networks Community structure Introduced species and biodiversity Invasive species

Terms such as individual, population, species, community and ecosystem all represent distinct ecological levels and are not synonymous, interchangeable terms. Here is your brief guide or …

Learn about the levels of organization in the biosphere, including biomes, ecosystems, communities, and populations.

Review your understanding of populations, communities, and ecosystems in this free article aligned to NGSS standards.

The distribution and abundance of organisms on Earth is shaped by both biotic, living-organism-related, and abiotic, nonliving or physical, factors. Ecology is studied at many levels, including …