Ecosystems consist of various non-living (abiotic) and living (biotic) components.
Abiotic includes various: -
-Physical factors – sunlight, shade, precipitation, wind, terrain, temperatures and water currents.
-Chemical factors – all elements and compounds in the atmosphere, hydrosphere and lithosphere that are essential for living organisms.
Biotic includes different types of plants and animals classified as, producers, consumers and decompose rs on the basis of their sources of energy and matter resources:
Producers /Autotrophs
These are organisms that produce their own food. Typical autotrophs in ecosystems are photo autotrophs such as plants, algae and photosynthetic bacteria, all of which use the energy in sunlight to make the energy-rich molecule, glucose; from carbon dioxide and water (nutrients are also required).
-Primary productivity is the rate at which energy is stored by photosynthetic activity of producer organisms, in the form of organic substances that can be used as food material.
-Gross Primary Production (GPP) is total photosynthesis.
-Net Primary Production (NPP)is gross photosynthesis minus respiration i.e.NPP = GPP – R. NPP is the amount of energy available to next tropic level made up of primary consumers e.g. herbivores.Reverse process is respiration
In some marine ecosystems where there is no light, there are chemoautotrophs, which make glucose from carbon dioxide and hydrogen sulphide in the water rather than the sun’s energy.
Consumers /heterotrophs
These are organisms that consume other organisms for food. Depending on their food sources consumers fall into three major
classes:
-Herbivores-'plant eaters' primary consumers that feed directly on all or part of a plant e.g. grasshoppers, cows etc.
-Carnivores 'animal eaters'. Secondary and higher level consumers which feed on plant eating animals e.g. lion
-Omnivores 'plant and animal eaters'...e.g. pigs, rats, cockroaches, humans etc.
Other consumer organisms in an ecosystem feed on dead plant and animal matter called detritus and are known as detritus consumers. They are of two classes
-detritus feeders—feed directly on dead plant or animal matter e.g. vultures, termites,
-Decomposers e.g. fungi, bacteria---carry the decomposition process of much of the detritus in ecosystems especially wood and leaves that is not eaten by detritus feeders but undergo decay, rot, or decomposition breaking the complex molecules into simple chemicals.
Parasites are other examples of consumers. They feed on a plant or animal (host) over an extended period of time without killing it – at least not immediately, but cause harm to it.
Scavengers are non-fungal, non-bacterial consumers that eat recently dead organisms that have been killed by other organisms or by accident
marto answered the question on March 20, 2019 at 07:04