Question

Define each of the following in a sentence: demography, density, distribution, and size as they relate to population ecology.

Draw both a J and S shaped growth curve on a single graph and explain in a short paragraph how they are related.

List two factors that contribute to environmental resistance.

Define the term carrying capacity (K) and describe in one sentence what happens to a population when K is exceeded.

Answer 1

Demography: The statistical study of population is termed as demography. It includes the study of birth, deaths, migrations, aging etc. to get the dynamic view of a population.

Density: It is defined as the distribution of people in unit area. It gives us the idea how abundant a population is and how densely they are distributed.

Distribution: The spreading of population in geographical area is termed as distribution. For ex. Distribution of population of human is less dense in desert as compared to mesophilic areas.

Size: Population size is defined as the no. of individuals actually residing at a place.

2. S shaped curve is sigmoidal while J is exponential curve. In S curve the

There is a a positive acceleration phase; followed by exponential growth rate as in the J-shaped curve; and later declines in a negative acceleration phase to zero growth rate until the population stabilizes.

List two factors that contribute to environmental resistance.

Biotic and abiotic are the factors that contribute to the environmental resistance.

Biotic factors include: predation, parasitism, competition and disease. While abiotic factors include flood, drought, temperature etc.

Define the term carrying capacity (K) and describe in one sentence what happens to a population when K is exceeded.

Carrying capacity(K) is defined as the maximum capacity of an ecosystem to withhold the population size upto a maximum extent with proper supply of food and shelter or we can say sustainably.

If K exceeded then, they will exhaust their source of food, water, or other requirement to sustain life and this will lead to the death of population which may extinct them.