Population Ecology Flashcards

What term describes the maximum number of individuals an environment can sustainably support?

Answer: Carrying capacity

Carrying capacity (K) is the maximum population size of a biological species that can be sustained indefinitely by a given environment, considering the available food, habitat, water, and other necessities. When a population reaches its carrying capacity, its growth rate typically slows down and stabilizes due to environmental resistance.

Which population growth model includes environmental resistance?

Answer: Logistic growth

The logistic growth model describes population growth that is initially exponential but slows as the population approaches its carrying capacity due to environmental resistance. This resistance includes factors like limited resources, predation, and disease, which become more impactful as the population density increases. In contrast, exponential growth assumes unlimited resources.

In population ecology, what does 'r' represent?

Answer: Intrinsic growth rate

In population ecology, 'r' represents the intrinsic rate of natural increase, or intrinsic growth rate. This value is the maximum potential growth rate of a population under ideal conditions, with unlimited resources and no environmental resistance. It is a key parameter in both exponential and logistic growth models.

Which of the following is a density-dependent factor?

Answer: Food availability

Density-dependent factors are those whose impact on a population's growth rate or mortality increases as the population density increases. Food availability is a classic example; as a population grows, competition for limited food resources intensifies, leading to lower birth rates or higher death rates. Natural disasters and temperature extremes are typically density-independent.

What type of survivorship curve is typical of species that produce many offspring with low survival rates?

Answer: Type III

A Type III survivorship curve is characteristic of species that produce a large number of offspring but provide little to no parental care, resulting in very high mortality rates early in life. However, those few individuals that survive their early vulnerable stages tend to live relatively long lives. Examples include many insects, fish, and marine invertebrates.

Which strategy is characteristic of K-selected species?

Answer: High parental investment

K-selected species are characterized by traits that are advantageous in stable environments where populations are near their carrying capacity. These traits include fewer offspring, larger body size, longer life spans, and significant parental investment to ensure the survival of their limited progeny. This strategy contrasts with r-selected species, which prioritize high fecundity and early maturity.

Which population dispersion pattern is most common in nature?

Answer: Clumped

Clumped dispersion is the most common pattern observed in nature, where individuals are aggregated in patches. This pattern often occurs due to patchy resource distribution, social behaviors (like schooling or herding), or limited dispersal abilities. It allows individuals to benefit from group living or exploit localized resources more effectively.

What does a population pyramid primarily show?

Answer: Age & sex distribution

A population pyramid, also known as an age-sex pyramid, is a graphical illustration that shows the distribution of various age groups in a population, typically broken down by sex. It provides insights into a population's past growth trends, current structure, and future demographic potential, indicating whether a population is growing, stable, or declining.

Which term refers to the number of individuals per unit area?

Answer: Population density

Population density is a fundamental concept in ecology, defined as the number of individuals of a species per unit area or volume. It is a crucial metric for understanding how a population interacts with its environment and for assessing factors like resource competition, disease transmission, and predation pressure.