5.3 A Green World Ecology What is ecology? is the branch of biology which studies the relationships between living organisms (including humans) and their physical environment, and tries to understand the vital connections between plants, animals and the world around them. Ecology also provides information about the benefits of ecosystems and how we can use Earth’s resources in ways that leave the environment for future generations. Ecology 1 healthy The central principle of ecology is that each living organism has a constant relationship with all the other elements that make up its environment, which consists of: , such as climate and geology, and Abiotic factors , such as members of the same species and other species that share a – the place or environment where plants or animals naturally or normally live and grow. Biotic factors habitat MORE The word comes from the Greek: , “house,” or “environment”; , -λογία “study of.” 1 ecology oikos -logy Environment and ecosystem An is a biological community of interacting organisms and their physical environment. It is a dynamic entity which is controlled by: ecosystem , such as climate and the , which control the overall structure of an ecosystem and the way things work within it, but are not influenced by the ecosystem itself: they simply exist; External factors soil , such as the availability of resources, decomposition, root competition, or , which are factors that both control and are controlled by the ecosystem interaction and change according to the relationship of different species with one another . Internal factors shading 2 Ecosystems provide benefits, called , on which we depend for our and wellbeing, such as food, fresh water, wood, fibres, genetic resources and medicines. They support directly or indirectly our survival and quality of life. ecosystem services livelihood MORE For example, if one species contracts a disease and dies off, this affects the whole system. Humans operate within ecosystems and the effects of human activities can influence both internal and external factors. Global warming is an example of a cumulative impact of human activity. 2 New branches of ecology is the study of questions about the living and non-living components within the environment, how these factors interact with each other, and how natural and human-induced changes affect how they function. Ecosystem ecology is a multidisciplinary science that has two central goals: Conservation biology evaluating human impact on biological diversity, and developing practical approaches to prevent the extinction of species and maintain the integrity of ecosystems. is the scientific study of repairing disturbed ecosystems through human intervention. While conservation biology is focused on preventing ongoing degradation, restoration ecology seeks to actively reverse such degradation: it aims at recreating, initiating, or accelerating the of an ecosystem that has been disturbed . Restoration ecology recovery 3 MORE Common include , rivers, intense grazing, hurricanes, floods, and fires. Restoration activities may be designed to replicate a pre-disturbance ecosystem or to create a new ecosystem where it had not previously existed. 3 disturbances logging damming