Differentiate between the terms critical number and carrying capacity. What is density dependence?

Question

What will be an ideal response?

Answer 1

Critical number is the minimum size of a population below which it will not reproduce. The survival of the species is unlikely below the critical number. The carrying capacity is a characteristic of an ecosystem and "is the upper limit to the population of any particular species that an ecosystem can support. . . ." Therefore, the critical number is the smallest number of individuals within a species that is required for the species survival while the carrying capacity is the largest number of individuals within a species that an ecosystem can support. Carrying capacity is a characteristic of an ecosystem, while critical number is a characteristic of the species. Density-dependent factors are those environmental resistance factors that, as the population size increases, contribute to an increase in "mortality, (such) that population growth ceases or declines." As population size decreases, environmental resistance factors decrease as well, allowing the population to grow again. Density-independent factors are those that cause mortality irrespective of the population density. The population size can be small or large and the factor will have the same effect (e.g., a sudden, hard freeze will kill plants, seeds, or animals irrespective of the population size).