Populations and Communities Flashcards

Carrying Capacity

The maximum population size of a species that can be sustained long-term by a given environment.

Limiting Factors

Environmental factors that restrict the growth, distribution, or abundance of a population or organism within an ecosystem.

Density-Dependent Limiting Factors

Factors that have a greater impact on population size as the population density increases.

Interspecific Competition

Competition between organisms of different species.

Intraspecific Competition

Competition between organisms of the same species.

Density-Independent Limiting Factors

Factors that impact population size regardless of its density.

Exponential Population Growth

Population growth in ideal conditions, resulting in a J-shaped growth curve.

Sigmoid Population Growth

S-shaped growth curve that occurs in environments with limited resources.

Natality (N)

The birth rate of a population.

Immigration (I)

Individuals entering a population.

Mortality (M)

The death rate of a population.

Emigration (E)

Individuals leaving a population.

Positive Population Growth

Occurs when natality and immigration are greater than mortality and emigration (N + I > M + E).

Transitional Phase

Growth phase where natality and immigration are slightly greater than mortality and emigration.

Plateau Phase

Growth phase where natality and immigration are equal to mortality and emigration, resulting in constant population size.

Negative Population Growth

Occurs when natality and immigration are less than mortality and emigration (N + I < M + E).

Intraspecific Interactions

Interactions between organisms of the same species, including competition and cooperation.

Parasitism

A symbiotic interaction where one organism benefits (parasite) and the other is harmed (host).

Commensalism

A symbiotic interaction where one organism benefits and the other is neither helped nor harmed.

Mutualism

A symbiotic interaction where both organisms benefit.

Invasive Species

Non-native species that, when introduced, cause harm to the ecosystem and outcompete native species.

Top-Down Control

Regulation of lower trophic levels by the presence and activities of organisms at higher trophic levels.

Bottom-Up Control

Influence of resource availability at lower trophic levels on the abundance and distribution of organisms at higher trophic levels.

Allelopathy

Chemical inhibition where organisms release compounds that affect the growth or survival of nearby organisms.

Antibiotic Secretion

The process where microorganisms secret antibiotics to hinder the growth of other bacteria.

Predation

A feeding relationship where a predator captures and consumes its prey.

Cycling in Predator-Prey Relationships

The cyclical pattern of population increases and decreases driven by predator and prey interactions.

Environmental Resistance

Factors that limit the growth of a population as it reaches the carrying capacity.

Anthropogenic Events

Events caused or influenced by human activities that affect ecosystems.

Exponential Growth Phase

Phase of rapid population growth when conditions are ideal and resource availability is high.

Transitional Phase with Environmental Resistance

Phase where growth slows due to increasing density-dependent factors.

Bacterial Growth in Lab as Example

Illustrates exponential growth under ideal conditions with unlimited resources.

Kudzu in the U.S.

An invasive species that outcompetes native plants and hinders their growth.

Grey Wolves in Yellowstone

An example of top-down control where reintroduction affects many trophic levels in the ecosystem.