Ecology is the study of interactions between biotic and abiotic factors in ecosystems. It is concerned with issues like climate change, extinction, and endangered species. Ecosystems can be analyzed at different levels of organization from the biosphere down to populations of individual species. Organisms are interdependent on biotic and abiotic factors in their environment, and populations are regulated by density-dependent and independent factors. Populations grow through birth and immigration and decline through death and emigration, and their growth can be measured over time.

1. Ecology

16. Types of Growth