Aquatic ecology and Biodiversity

Unit 1- Aquatic ecology

1.2.2. Ecological components

• Species
• Population
• Communities
• Ecosystem
• Biosphere

Species
It is a natural group of actually or potentially interbreeding individuals reproductively isolated from other such groups. Eg. Sardinella sp. Catla sp.
Population
All the individuals of a particular species or several related species of plants and /or animals in a unit area and unit time constitutes ecological population.
• Nonspecific population (only one species)
• Poly/mixed specific population (Several Species)
Example: - Barnacles population, Mackerel population, oysters population
Community
Biotic community is assemblages of several species of population that tend to occur together in various geographical areas constitute an ecological community.
Example :- Rocky shore community, coral reef community, sandy shore community
algal community etc.
The community also called as ‘Bio Conenoses’ (Karl Mobius, 1977)
• Phyto Coenosis – Plant Community
• Zoo Coenosis – Animal Community
Ecosystem
Ecosystems are dynamic interactions between plants, animals and microorganisms and their environment working together as a functional unit. Ecosystems in nature, work as all the parts work together to make a balanced system. An ecosystem is a community of living and non-living things that work together. It can be as large as a desert or a lake or as small as a pond or a puddle. No community can carry more organisms than its food, water and shelter that can accommodate. Food and territory are often balanced by natural phenomena such as fire, disease, and the number of predators. Each organism has its own niche or role to play. The major parts of an ecosystem are soil, atmosphere, heat and light from the sun, water and living organisms.
Biosphere
The biosphere is the biological component of earth systems, which includes the lithosphere, hydrosphere, atmosphere and other spheres. The biosphere includes all living organisms –plants, animals, bacteria, fungi etc. on earth, together with the dead organic matter produced by them.