Population regulation, Biology

Assignment Help:

Population Regulation

The number of individuals in a natural population varies with time. If the size of a population declines too drastically due to some reason, it may become extinct, but may later be re-established by immigration from other populations. On the other hand, increase in size of a population is not infinite since the carrying capacity of the environment always imposes a restriction upon it. In spite of such fluctuations, however, an outstanding feature of most large populations is that their average size changes relatively little over the years and certainly less than is expected from their biotic potentials. This indicates that population sizes are regulated in such a way that small population grow fast, larger populations grow more slowly and still larger populations decline.

Let us see what brings about such ecological homeostasis. In low-diversity, physically stressed ecosystems or in those subjected to irregular or unpredictable external perturbations, populations tend to be regulated by physical components such as weather, water, chemical limiting factors, pollution etc. In high diversity ecosystems, or in those which are not physically stressed, populations tend to be biologically controlled. In all ecosystems there is a strong tendency for all populations to evolve through natural selection towards self-regulation such as failure of reproduction and self-inflicted mortality. Even though this is difficult to achieve under external stress. It is because over-population is not in best interests of any population. Thus it can be said that limitation of number in any population is brought about by the action and interaction of two basic regulatory processes namely density dependent and density independent factors. We will discuss these processes in the following subsections.


Related Discussions:- Population regulation

What are the major significant organic molecules for humans, Q. What are th...

Q. What are the major significant organic molecules for living beings? Ans. There are many types of organic molecules that are important for the living beings. Particularl

Define etiological risk factors in cancer, Define Etiological Risk Factors ...

Define Etiological Risk Factors in Cancer? Cancer risks are climbing because of increasingly sedentary lifestyles and diets which are high in fat and sugar although low in frui

Define the visual accommodation, Q. What is visual accommodation? Visua...

Q. What is visual accommodation? Visual accommodation is the phenomenon of varying the curvature of the crystalline lens to make possible the difference of its refractivity to

Assessment of exstrophy of the bladder, Assessment You can observe it...

Assessment You can observe it visually at birth. The anterior abdominal wall is absent and the posterior bladder lining which is bright red in colour is exposed. Urine seeps

Invertebrete zoology, give an example invertebrate phylum/phyla for protopl...

give an example invertebrate phylum/phyla for protoplasmic grade organization

Explain the food preparation and cooling - canning, Explain the Food prepar...

Explain the Food preparation and Cooling - Canning? Food preparation - Preparation methods will change with the type of food. For fruit, cutting to size, washing, grading, peel

What are similarities between reptiles and birds, Q. What similarities do r...

Q. What similarities do reptiles and birds share regarding external coverage, reproduction and excretion? Regarding external coverage, birds are similar to reptiles as they pre

Mechanism of respiration in cockroach, MECHANIS M - Tergo-sternal m...

MECHANIS M - Tergo-sternal muscles are relaxed. Volume of cavity is increased and pressure is decreased. To full fill the pressure air comes through the passage & mixed

Explain the structural and functional changes in cancer , Identify and brie...

Identify and briefly explain the structural and functional changes that occur in the large bowel when colorectal cancer develops.

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd