ENVIRONMENTAL BIO 2.2 POPULATION ECOLOGY

What do population ecologists study?

population size, distribution, growth rate, and factors that influence these metrics such as resource availability and predators

What is a population in ecology?

All individuals of a species living in the same geographic area who can interact and interbreed.

What is a population’s range

The geographic area where a species or one of its populations can be found.

What is population distribution?

The location and spacing of individuals within their range

Name the three basic types of population distribution patterns.

Clumped, random, and uniform

What does clumped population distribution mean?

Individuals are found in groups or patches within their habitat.

What characterizes random population distribution?

Individuals are spread out with no discernible pattern.

What is uniform distribution?

Individuals are spaced evenly, often due to territorial behavior.

Define population dynamics.

Changes over time in population size and composition.

What is minimum viable population?

The smallest number of individuals needed to allow a population to persist or grow in the long term.

What is carrying capacity?

The maximum population size that an environment can support indefinitely

What problems occur when population density is too high?

Disease spreads, resources become insufficient, and social behaviors break down

What problems result from population density being too low?

Group behaviors fail, mates are hard to find, and genetic diversity drops.

What is exponential growth?

Population size increases rapidly when growth is unrestricted, producing a J-shaped curve.

When does exponential growth usually occur?

When species enter a new environment or resources increase suddenly.

What is logistic growth?

Population growth slows as it nears carrying capacity, producing an S-shaped curve

What limits population growth?

Density-dependent (e.g., predation, disease) and density-independent (e.g., natural disasters) factors

What is top-down regulation?

: Population size limited primarily by predation from organisms at the top of the food chain

What is bottom-up regulation?

Population size limited by the availability of resources for those at the base of the food chain.

What is a trophic cascade?

Effects throughout the food chain triggered by changes in the population of top predators.

What is an r-selected species?

Species with high biotic potential, short life span, early maturity, many small offspring, little parental care, adapted to unstable environments

What is a K-selected species?

Species with lower biotic potential, long life span, later maturity, fewer large offspring, more parental care, adapted to stable environments

Why were wolves reintroduced to Yellowstone in 1995?

To help restore population balance and ecosystem health following declines due to predator control.

What impacts did the recent high hunting rates have on Yellowstone wolves?

Reduced pack size and hunting efficiency, requiring 4–5 years for pack recovery if hunting stays high

What role do wolves play in Yellowstone’s ecosystem?

As top predators, they regulate elk and other prey populations, influencing the entire food chain

What is the current management situation for Yellowstone wolves?

Some packs are protected, while hunting is allowed in other areas; U.S. Fish & Wildlife Service is reconsidering protections.