Ecology: Population Dynamics, Interactions, and Conservation

Sex Ratio

The ratio of males to females in a population.

Generation Time

The average time between the birth of individuals and the birth of their offspring.

Age Structure

The distribution of individuals of different ages within a population.

Population Density

The number of individuals per unit area or volume, calculated by dividing the total population by the area or volume.

Quadrat Sampling

A method of sampling where a specific area (quadrat) is marked and studied to estimate population density.

Mark and Recapture

A method used to estimate population size by capturing individuals, marking them, releasing them, and later recapturing to see how many are marked.

Exponential Growth

A growth pattern where the population size increases rapidly in proportion to its current size, typically occurring in ideal conditions.

Logistic Growth

A growth pattern where the population grows rapidly at first but slows as it approaches carrying capacity due to resource limitations.

Population Growth Rate

The rate at which a population increases or decreases in size over a specific period.

Doubling Time

The time it takes for a population to double in size.

Population Dispersal Patterns

The spatial distribution of individuals within a population, which can be clumped, uniform, or random.

Clumped Distribution

A population distribution pattern where individuals are grouped together in patches.

Uniform Distribution

A population distribution pattern where individuals are evenly spaced across an area.

Random Distribution

A population distribution pattern where individuals are spread randomly without a predictable pattern.

Survivorship Curves

Graphs that represent the number of individuals surviving at each age for a given species.

Type I Survivorship Curve

A curve characterized by high survival rates in early and middle life, with a steep decline in later life.

Type II Survivorship Curve

A curve that depicts a constant rate of survival throughout life.

Type III Survivorship Curve

A curve characterized by low survival rates for the young, with a higher survival rate for those that reach a certain age.

Rapid Life-History

A reproductive strategy characterized by high fecundity, early maturity, and short lifespan.

Slow Life-History

A reproductive strategy characterized by low fecundity, late maturity, and long lifespan.

Resource Availability

The abundance of resources necessary for survival and reproduction in a given environment.

Carrying Capacity

The maximum population size that an environment can sustain indefinitely without degrading the habitat.

Limiting Factor

Any biotic or abiotic factor that restricts the size of a population.

Biotic Factors

Living components of an ecosystem that affect population size, such as predators, prey, and competitors.

Abiotic Factors

Non-living components of an ecosystem that affect population size, such as temperature, water, and nutrients.

Density-Independent Limiting Factors

Factors that affect population size regardless of the population's density, such as natural disasters.

Density-Dependent Limiting Factors

Factors that affect population size based on the population's density, such as competition and disease.

Symbiosis

A close ecological relationship between two or more different species.

Mutualism

A type of symbiotic relationship where both species benefit.

Commensalism

A type of symbiotic relationship where one species benefits and the other is neither helped nor harmed.

Parasitism

A type of symbiotic relationship where one species benefits at the expense of the other.

Intraspecific Competition

Competition between individuals of the same species for limited resources.

Interspecific Competition

Competition between individuals of different species for limited resources.

Predation

An interaction where one organism (the predator) kills and eats another organism (the prey).

Herbivory

An interaction where an organism (herbivore) feeds on plants.

Resource Partitioning

The division of resources among species to reduce competition.

Character Displacement

The phenomenon where differences among similar species are accentuated in areas where they coexist.

Competitive Exclusion

The principle stating that two species competing for the same resources cannot coexist at constant population values.

Niche Partitioning

The process by which competing species use the environment differently to coexist.

Ecological Equivalents

Species that occupy similar niches but live in different geographical regions.

Biodiversity

The variety of life in a particular habitat or ecosystem.

Biodiversity Hot Spots

Regions with a high level of endemic species that are under threat from human activities.

Keystone Species

A species that has a disproportionately large effect on its environment relative to its abundance.

Disturbances

Events that change the structure of an ecosystem, such as fires or floods.

Habitat Loss

The destruction or alteration of a habitat, leading to a decline in species populations.

Habitat Fragmentation

The process by which a habitat is broken into smaller, isolated patches.

Wildlife Bridges

Structures that allow animals to cross human-made barriers safely.

Edge Effect

The changes in population or community structures that occur at the boundary of two habitats.

Habitat Degradation

The decline in the quality of a habitat due to human activities.

Indicator Species

Species that reflect the health of an ecosystem and can indicate changes in environmental conditions.

Non-Native Species

Species that are introduced to an area where they do not naturally occur.

Invasive Species

Non-native species that spread widely and cause harm to the environment, economy, or human health.

Ecosystem Stability

The ability of an ecosystem to maintain its structure and function in the face of disturbances.

Ecosystem Resilience

The capacity of an ecosystem to recover from disturbances and return to its original state.

Ecosystem Resistance

The ability of an ecosystem to remain unchanged when subjected to disturbances.

Ecological Succession

The process of change in the species structure of an ecological community over time.

Primary Succession

Succession that occurs in an area where no soil exists, such as after a volcanic eruption.

Pioneer Species

The first species to colonize previously disrupted or damaged ecosystems.

Climax Community

A stable community that no longer goes through major ecological changes.

Secondary Succession

Succession that occurs in an area where a disturbance has destroyed an existing community but left the soil intact.