Concept of Carrying capacity, Population growth and Regulation, Population Fluctuation

Concept of Carrying capacity, Population growth and Regulation, Population Fluctuation

1. Carrying Capacity, Population Growth and Regulation and Population Fluctuation Made By- Drupad Malik M.Sc. Env. Sc. Semester- I

2. Table of content 01.Carrying Capacity Basic concept, factors affecting carrying capacity 02. Population Growth and Regulation Survival ship curves, types of growth forms, Density Dependent and In-dependent factors 03. Population Fluctuation Types of population fluctuations

3. Population is the group of individuals of same species occupying same area or space at a specific time period They are capable of interbreeding. Study of statistical changes in population is called as the Demography Population ecology  is the branch of ecology that studies the structure and dynamics of populations. Before Going forward we should know about population. What is Population ?

4. Carrying Capacity Defination, Concept and factors involved 01.

5. Its is the capacity of a habitat to hold or sustain the maximum population size or load of a given specie without being degraded is called Carrying Capacity. The carrying capacity depends upon the various environmental factors such as limit food, space and other resources etc. are some of the factors with controls the carrying capacity of a habitat. These factors are also known as Environment Resistance which controls the growth of the species. Ecological Debt – It refers to the consumption of resources from the ecosystem is more than its regenerative capacity. It is closely related to Carrying Capacity What is carrying capacity ?

6. Population Growth and Regulation Survival ship curves, types of growth forms, Density Dependent and In-dependent factors 02.

7. Population growth is the increase in the number of individuals in a population occupying a particular place or a territory during a time period. The population growth is influenced by the three major factors which are- a. Death Rate or Mortality b. Birth Rate or Natality c. Migration – Immigration and Emigration The population growth is expressed in two ways a. Absolute number b. Percentage Annual Growth Rate – It is the percent of increase in number of individuals per annual In the annual growth rate, the percentage may decline but the absolute number always increases What is population growth?

8. As we have discussed in the previous slide that the population size or change in population size depends upon the birth, death and migration. Therefore, the population changes over time which is also known as Population Dynamics . The death of the individuals can be studied with the help of survivorship curve. There are three kinds of survivorship curves Survivorship Curve I – It is of convex shape. In this the individuals survive till old age then they die rapidly. E.g.- Human population. Survivorship Curve II – It is a diagonal line. In this the population has the chance of death at any age of there life. Environment has more harsh effect on the young ones than old. E.g.- Population of Birds Survivorship curve III – It is of concave shape. In this the death rate is high at young age and much lower death rate at older. E.g.- Plant populations, some animal populations etc. Survivership Curves

9. There are two types of population growth. Exponential Population Growth In this the population of a species continuously beyond the carrying capacity in the presence of unlimited resources. This type of population shows a J-shaped curve . Individuals in populations with a high rate of growth typically reproduce early in life, have short generation times (the time between successive generations), can reproduce many times, and have many offspring each time they reproduce. E.g.- Rodents like rats. 2. Logistic Population Growth In this the population grows but a level or a point comes where growth becomes stable this point or level is known as carrying capacity (K) which we have discussed earlier slides This is due to limited food, space and other resources or we can say that environment resistance factors or limiting factors helps to stabilize the growth of population. Types of Population Growth

10. Population Density - It is the number of individuals per unit area or volume. There are two types of limiting factors responsible for population regulation 1. Density Dependent Factors which depends upon the density of a population of a species. It include diseases, competition and predation. These factors either have positive or negative correlation to the population size. With positive relationship , these limiting factors increase with size of the population and control the growth of population. With negative relationship , the limiting factors effectively act on low density and limiting factors becomes less effective when the population grows, or their density increases. 2. Density Independent Factors which doesn’t depends upon the density of population of a species these factors include natural disasters, environmental stress, pollution etc. are some of the density independent factors Population Regulation

11. Population Fluctuation 03.

12. In nature nothing is stable. Generally, we see the four types of population fluctuations – Stable - A species whose population size varies marginally above and beneath it carrying capacity is said to have a genuinely steady population size. e.g.- undisturbed tropical forest, where normal temperature and precipitation fluctuate little from year to year. Irruptive - population growth may every so often explodes, or irrupt, to a high peak and afterward collide with a more steady lower level or sometimes to an exceptionally low level. e.g. - in calm or temperate environments, the insect populations develop quickly throughout the spring furthermore, summer and afterwards crash during the hard ices of winter. Cyclic - populations rise and fall over a predictable period of time. E.g.- Snowshoe hare is the primary food of the lynx. The population cycles of these two species are closely linked. Their populations generally rise and fall in a 10-year cycle. Irregular – Population with no regular pattern of rise and fall. e.g.- irregular population fluctuations in migratory Pacific and Atlantic dunlins Population Fluctuation

13. Resources Books Master Success Series Textbook of Zoology by Dr. Riaz-Ul- Haq - Ramay . Pg. No. 190,191,192 Website references https://www.magnetbrains.com/course/class-12-geography-ncert/ https://www.nature.com/subjects/population-dynamics https://www.enr.gov.nt.ca/en/services/lynx/lynx-snowshoe-hare-cycle#:~:text=Snowshoe%20hare%20is%20the%20primary,carrion%20when%20hares%20are%20scarce . http://www.sfu.ca/biology/wildberg/NewCWEPage/papers/XuetalPopEcol2015.pdf

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