Ecology is the study of the relationships between living organisms, including humans, and their physical environment. It is a branch of biology that considers organisms at the individual, population, community, ecosystem, and biosphere level. Ecology overlaps with other sciences such as biogeography, evolutionary biology, genetics, ethology, and natural history. The term "ecology" was coined by the German scientist Ernst Haeckel in 1866.

Ecologists study the abundance, biomass, and distribution of organisms in the context of the environment; life processes, interactions, and adaptations; movement of materials and energy through living communities; successional development of ecosystems; cooperation, competition, and predation within and between species; and patterns of biodiversity and its effect on ecosystem processes. Ecology is not synonymous with environmentalism, and it is as much a biological science as it is a human science.

Ecology helps us understand how organisms live with each other in unique physical environments. Ecologists study relationships among organisms and habitats of many different sizes, ranging from the study of microscopic bacteria growing in a fish tank to the complex interactions between the thousands of plant, animal, and other communities found in a desert. Ecology also provides information about the benefits of ecosystems and how we can use Earths resources in ways that leave the environment healthy for future generations.

In summary, ecology is a broad field that encompasses the study of living organisms and their physical environment, and it provides valuable insights into the relationships between organisms and their surroundings.