Skip to main content

CBSE class 12th biology notes Population and Population Growth

CBSE class 12th biology notes Population and Population Growth

There are four variables/ causes that govern the population growth/population size:
  1. Birth rate(Natality): It is defined as a number of births per 1000 individuals in one year.
  2. Death rate (Mortality): It is defined as a number of death per 1000 individuals per year.
  3. Immigration: Entry of individuals in a given population.
  4. Emigration: Exit of individuals from a given population.
A population gains individuals by birth and immigration and loses them by deaths and emigration.
Thus, population change = (Births + Immigration) – (Deaths + Emigration)
Effect of Age Distribution on Population growth
In many organisms, the generations overlap. It is shown, from a theoretical point of view, that competition between the different ages classes in such organisms will have important population dynamics consequences. Strong competition between age classes can be either a stabilizing or destabilizing force depending on the stage of the life cycle—juvenile survival or adult survival/reproduction—at which density dependence occurs. When juvenile survival is density dependent, competition has a stabilizing effect. On the other hand, when reproduction is density dependent, strong competition tends to be destabilizing, i.e. it will cause population density to fluctuate. It is also shown that delayed effects on reproduction, caused by strong competition as the adults grow up, tend to be destabilizing. These findings have interesting implications for the population dynamic behavior in organisms with different types of life cycles, and these theoretical findings might be relevant to the interpretation of patterns of population dynamic behavior.
For School courses, live classes, Professional courses, and Digital Marketing courses, Class 12 Science Online Classes kindly visit www.takshilalearning.com 

Labels

Labels:

Comments

Post a Comment

Thank you we will contact ASAP.

Popular posts from this blog

Online cbse coaching class for 11 Mathematics

Online cbse Class 11 maths : Online coaching classes for 11 maths  and for other subjects. We are here to solve students problem instantly, So that they can improve himself/herself. One to One Correspondence and Equivalent Sets Suppose the members of the family are dinning and plates are prepared on the table then there is a One to one correspondence between the set of family members and the plates prepared. We will indicate this correspondence by the symbol If each element of a set A is associated with one and only one element of a set B and each element of B is associated with one and only one element of set A, then the sets A and B are said to be in one to one correspondence. If both the sets are finite and if they are in one to one correspondence, it is obvious that they have the same number of elements. If two sets have the same number of elements, they are said to be equivalent sets. Using symbol, we write A B. Between two equivalent sets, a one to one corr...
Post a Comment
Read more

Best Sample papers for Bank PO Exam Download

Sample papers for Bank PO Exam | Question Paper for Bank PO : Institute of banking Personnel Selection (IBPS) Department issued a Notification of IBPS PO 2017  exam announced in October month. IBPS Probationary Officer (PO) Online Application Form process will be begin from July 2017. This is a hard exam for all students so aware of its value. Large number of  candidates will participate in this exam. So all candidates should prepare well for it. Check out IBPS, Bank PO Sample papers, Question Paper Pattern, SBI  PO Syllabus ,   IBPS Syllabus  and other IBPS PO Preparation 2017 This paper is identical to any Bank PO Question Paper Pattern. Check whole IBPS Bank “PO question paper” subject wise. IBPS (PO) Paper Pattern Analysis with Syllabus and main topics of IBPS Exam 2017. PO Question Paper Pattern, Bank PO sample Papers for IBPS Bank Exam IBPS PO Exam will be conducted at three levels 1st- PO Preliminary Exam 2nd- PO Mains Exam 3rd- PO Common ...
Post a Comment
Read more

What is the difference between human and physical capital

Difference between human and physical capital Human capital refers to a worker's abilities, education, ability, and other attributes that influence his or her productive capacity and earning potential. Physical capital Presence of trade barriers lead to mobility restriction. Process of formation is economic and technical. Physical capital is separable from the owner. Possibility of trading physical capital in the market exists. Continuous use leads to depreciation. Financial statements are present. Human capital Culture and nationality lead to mobility restriction. Process of formation is conscious and social process. Human capital is not separable Services rendered by the human capital can only be sold. Ageing leads to the depreciation but it can be minimized up to some extent. Financial statements are absent. Click to know for Importance and Impact of human capital on economic growth Tag - class 9 social science , class 9 economics, Human capital meaning, school online classes
Post a Comment
Read more