5.3 A GREEN WORLD 112 The word ecology comes from the Greek: , house , or environment ; - , study of . 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. Common disturbances include logging, damming rivers, intense grazing, hurricanes, floods, and fires. Restoration activities may be designed to replicate a predisturbance ecosystem or to create a new ecosystem where it had not previously existed. ONLINE RESOURCES Ecosystems damming: sbarramento disturbance: disturdo, alterazione healthy: sano livelihood: esistenza logging: disboscamento recovery: ripresa shading: ombreggiatura soil: terreno ECOLOGY What is ecology? 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 healthy for future generations. 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: abiotic factors, such as climate and geology, and biotic factors, such as members of the same species and other species that share a habitat the place or environment where plants or animals naturally or normally live and grow. Environment and ecosystem An ecosystem is a biological community of interacting organisms and their physical environment. It is a dynamic entity which is controlled by: external factors, such as climate and the soil, 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; internal factors, such as the availability of resources, decomposition, root competition, or shading, 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 . Ecosystems provide benefits, called ecosystem services, on which we depend for our livelihood and wellbeing, such as food, fresh water, wood, fibres, genetic resources and medicines. They support directly or indirectly our survival and quality of life. New branches of ecology Ecosystem 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 both natural and humaninduced changes affect how they function. Conservation biology is a multidisciplinary science that has two central goals: evaluating human impact on biological diversity, and developing practical approaches to prevent the extinction of species and maintain the integrity of ecosystems. Restoration ecology 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 recovery of an ecosystem that has been disturbed. 244 Think green MechPower.indb 244 30/01/24 17:09