Population and communication ecology

population

A group of individuals of the same species living in a specific area, capable of interbreeding and sharing genetic information.

community

A group of different species living in the same area, interacting with one another and sharing resources.

population ecology

The branch of ecology that studies the dynamics of population sizes, densities, and the interactions between populations and their environment.

population size

The total number of individuals in a population at a given time, often used to assess population health and dynamics.

population density

The number of individuals of a species per unit area or volume, indicating how crowded a population is in its habitat.

population distribution

The way in which individuals are spread across a specific area, often influenced by environmental factors and resource availability.

sx ratio

The sex ratio is the proportion of males to females in a population, typically expressed as the number of males per hundred females, influencing reproductive dynamics and population structure.

age structure

The age structure of a population refers to the distribution of individuals of various ages within that population, which impacts growth rates and reproductive potential.

limiting resource

A resource that is in limited supply and restricts the growth, abundance, or distribution of a population.

density dependent factor

A density dependent factor is a variable that affects a population's growth and survival in relation to its density, such as food availability, disease, and competition, becoming more significant as population density increases.

carrying capacity

The maximum population size that an environment can sustain indefinitely, given the available resources and environmental conditions.

density independent factor

A density independent factor is an environmental factor that impacts population size regardless of the population's density, such as natural disasters or climate changes.

population growth models

are mathematical representations that describe how populations change over time, incorporating factors like birth rates, death rates, immigration, and emigration.

population growth rate

The rate at which the number of individuals in a population increases or decreases in a given time period, influenced by birth and death rates.

intrinsic growth rate

The maximum rate at which a population can grow under ideal conditions, with unlimited resources and no environmental resistance.

exponetial growth model

describes a population that grows rapidly when resources are abundant and environmental resistance is minimal, leading to a J-shaped growth curve.

j shaped curve

A graphical representation of exponential growth, illustrating the rapid increase in population size over time, resembling the letter "J".

Logistical growth model

describes a population that grows rapidly initially but slows as it reaches carrying capacity, resulting in an S-shaped growth curve.

s shape curve

A graphical representation of logistic growth, showing how a population grows quickly at first and then levels off as it approaches the environment's carrying capacity, resembling the letter "S."

overshoot

occurs when a population exceeds its carrying capacity, leading to a decline in numbers due to resource depletion.

die off

refers to a significant decline in a population size, often caused by a lack of resources, disease, or predation, particularly after an overshoot of carrying capacity.

K selected species

are organisms that produce fewer offspring, invest more in parental care, and typically thrive in stable environments with limited resources.

R selected species

are organisms that produce many offspring, invest little in parental care, and often thrive in unpredictable or changing environments.

survivorship curves

graphical representations that show the number of individuals surviving at each age for a given species, illustrating different patterns of mortality.

Type one survivorship curve

Represents low mortality rates in early and middle life, with increased mortality in older age, typical of K-selected species.

Type two survivorship curve

Represents a constant mortality rate throughout the lifespan of individuals, indicating that the chance of death is independent of age.

type three survivorship curve

Represents high mortality rates in early life stages, with those surviving to adulthood having greater longevity, typical of r-selected species.

corridor

A linear landscape feature that facilitates the movement and dispersal of organisms between fragmented habitats, promoting biodiversity.

metapopulation

A group of spatially separated populations of the same species that interact through immigration and emigration, allowing for gene flow.

inbreeding depression

refers to the reduced biological fitness in a population due to mating between closely related individuals, which can result in harmful genetic traits.

community ecology

The study of interactions among different species living in the same area and how these interactions affect community structure and diversity.

symbiotic relationship

A close, long-term interaction between two different species.

competition

An interaction in which organisms vie for the same limited resources (such as food, space, or mates), negatively affecting both.

competitive exclusion principle

Two species that rely on exactly the same resources cannot coexist indefinitely; one will outcompete and eliminate the other.

resource partitioning

The division of resources among species to reduce competition and allow coexistence.

predation

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

parasitoid

An organism (often an insect) that lives in or on a host and eventually kills it as part of its life cycle.

parasitism

A relationship in which one organism (the parasite) benefits while the other (the host) is harmed but usually not killed.

pathogen

A disease-causing organism, such as a bacterium, virus, fungus, or parasite.

herbivory

An interaction in which an animal consumes plants or algae.

mutualism

A symbiotic relationship in which both species benefit.

commensalism

A relationship in which one species benefits while the other is neither helped nor harmed.

keystone species

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

ecosystem engineer

An organism that directly or indirectly modifies the environment, affecting habitat availability for other species (e.g., beavers building dams).