The word 'ecosystem' was coined on request, for a mentor, in 1935
Ecosystem feels like an ancient idea, but the word first appeared in print in 1935. The British ecologist Arthur Tansley wanted a term for the traffic of materials between living things and their surroundings, and asked his colleague Arthur Roy Clapham to invent one. Tansley even insisted ecosystems were partly 'mental isolates', drawn by observers.
An ecosystem is a set of organisms together with the physical environment they interact with, tied together by flows of energy and cycles of nutrients. Plants bring energy in through photosynthesis; animals move matter and energy around by eating plants and each other; decomposers break down dead material, returning carbon to the air and nutrients to a form plants and microbes can reuse.
Ecologists separate two kinds of control. External factors such as climate shape an ecosystem's structure without being shaped by it in return. Internal factors, including decomposition, competition between roots, shading and succession, both steer and respond to what happens inside. Ecosystems are never static; they are always recovering from some past disturbance. Staying close to equilibrium is called resistance, while absorbing a shock and reorganising yet keeping the same basic function and identity is called resilience.
After Tansley, the idea became quantitative. The limnologist G. Evelyn Hutchinson combined Charles Elton's thinking on food chains with the geochemistry of Vladimir Vernadsky and proposed that scarce minerals in a lake cap how much algae can grow, which in turn caps the animals that graze on them. Raymond Lindeman argued that energy flow drives the whole lake system. Hutchinson's students, the brothers Howard and Eugene Odum, built a systems approach for tracing energy and materials through nature.
People depend on what ecosystems supply: tangible goods such as water, food, fuel and medicinal plants, and services such as cleaning air and water, keeping oxygen in the atmosphere and pollinating crops. Soil loss, pollution, fragmented habitats, diverted rivers, suppressed fires and invasive species can degrade them gradually or tip them into sudden change. When a system loses its defining features, ecologists describe it as collapsed, and restoration is now linked to the Sustainable Development Goals.
Source: Ecosystem
