Test: Organisms and Population- Population attribute & Growth (February 18) - NEET MCQ

Demography is the study of human populations – their size, composition and distribution across space – and the process through which populations change. Births, deaths and migration are the 'big three' of demography, jointly producing population stability or change.

Mortality and emigration would necessarily decrease the density of a population in a given habitat.

Biotic potential is defined as the physiological capacity of organisms to produce their offspring under natural conditions. It is also called reproductive potential. In nature, the biotic potential of organisms is enormous but all the organisms do not survive due to the lack of food and space. There are also a number of diseases and the predatory organisms, that feed upon other organisms. The carrying capacity is the maximum number of individuals which the environment can support or sustain.

The density of a population in a given habitat during a given period changes due to changes in four basic processes, two of which (natality and immigration) contribute to an increase in population density and two (mortality and emigration) to a decrease. In a zero population growth density natality is balanced by mortality. 
 

Current human population growth appears to be J-shaped as we have either not yet met our population carrying capacity, or have exceeded the carrying capacity, but have not yet seen the population crash normally associated with J-shaped or exponential population growth. If the human population meets the carrying capacity it will closely resemble an S-shaped population curve.

Formula = the rate of change in population size) = (the contribution of each individual to population growth) x (the number of individuals in the population

Natality in population ecology is the scientific term for birth rate. Along with mortality rate, natality rate is used to calculate the dynamics of a population. They are the key factors in determining whether a population is increasing, decreasing or staying the same in size. Natality is the greatest influence on a population’s increase. Natality is shown as a crude birth rate or specific birth rate. Crude birth rate is used when calculating population size (number of births per 1000 population/year), whereas specific birth rate is used relative to a specific criterion such as age. By calculating specific birth rate, the results are seen in an age-specific schedule of births.

orrect option is

D

all of these

The rate of growth or decline of a population basically depends on four factors, including natality rate or births, mortality rates or death, and the emigration and immigration rates. These four factors affect the inflow and outflow of a population and hence, affects the growth and decline of a population.

So, the correct answer is 'All of these'

The genetic drift is a drastic change in allele frequency when population size is very small. Its effects are more marked in a small isolated population.

Exponential model is the one in which rate of change in anything is directly proportional to the number of the thing present. Exponential phase shows the exponential growth. Thus the size or the number increases at a constant growing rate.