Ecosystem Test - 8

In ecological pyramids, saprophytes do not have any place even though they play very vital role in ecosystem. This is because ecological pyramids does not take into account same species belonging to two or more trophic levels.

Carbon cycle is the most perfect biogeochemical cycle because carbon cycle operates globally. Carbon cycles include atmosphere, lithosphere and hydrosphere all together.

The characteristic of soils such as soil composition, grain size and aggregation determine the percolation and water holding capacity of the soil. Along with these pH and mineral composition determine the type of vegetation.

Some plants that are adapted to dry environments, such as cacti and pineapples, use the crassulacean acid metabolism (CAM) pathway to minimize photorespiration. This name comes from the family of plants, the Crassulaceae, in which scientists first discovered the pathway.

Instead of separating the light-dependent reactions and the use of CO​​​​​₂ in the Calvin cycle in space, CAM plants separate these processes in time. At night, CAM plants open their stomata, allowing CO​​​​​₂ to diffuse into the leaves.

In the daylight, the CAM plants do not open their stomata, but they can still photosynthesis. That's because the organic acids are transported out of the vacuole and broken down to release CO_{​​​​​2} which enters the Calvin cycle.

When resources are unlimited, a population can experience exponential growth, where its size increases at a greater and greater rate.

The important concept of exponential growth is that the population growth rate, the number of organisms added in each reproductive generation, is accelerating; that is, it is increasing at a greater and greater rate.

A nutrient cycle (or ecological recycling) is the movement and exchange of organic and inorganic matter back into the production of living matter.

Nutrient cycles occur within ecosystems. Ecosystems are interconnected systems where matter and energy flows and is exchanged as organisms feed, digest, and migrate about.

Ecosystems recycle locally, converting mineral nutrients into the production of biomass, and on a larger scale they participate in a global system of inputs and outputs where matter is exchanged and transported through a larger system of biogeochemical cycles.

Coexistence theory is a framework to understand how competitor traits can maintain species diversity and stave-off competitive exclusion even among similar species living in ecologically similar environments. Coexistence theory explains the stable coexistence of species as an interaction between two opposing forces: fitness differences between species, which should drive the best-adapted species to exclude others within a particular ecological niche, and stabilizing mechanisms, which maintains diversity via niche differentiation.

Resource partitioning, whereby interspecific competition is reduced because species compete primarily through differest resources, is a stabilizing mechanism.

Catabolism is the set of metabolic pathways that breaks down molecules into smaller units that are either oxidized to release energy, or used in other anabolic reactions.

Breakdown of detritus by microbial enzymes into simple forms is called catabolism in which mass of the organisms decrease without any external reduction in size of the organisms.

If a predator is too efficient and overexploits its prey, then the prey might become extinct and following it, the predator will also become extinct for lack of food. This is the reason why predators in nature are ‘prudent’. Prey species have evolved various defenses to lessen the impact of predation. Some species of insects and frogs are cryptically-coloured (camouflaged) to avoid being detected easily by the predator.