Biodiversity, Evolution, and Ecological Niches

Vocabulary practice flashcards covering biodiversity levels, evolutionary mechanisms, speciation, ecological niches, and extinction events.

Ecosystem Diversity

The variety of habitats that exist within a given region.

Species Diversity

The number of species in a region or habitat (a community or ecosystem).

Genetic Diversity

The range of different inherited traits within a species.

Species Richness

The number of different species represented in an ecological community, landscape, or region.

Species Evenness

The commonness or rarity of a species; it requires knowing the abundance of each species relative to those of the other species within the community.

Microevolution

A change in gene frequency within a population that can be observed over short periods of time.

Macroevolution

Major evolutionary change, applying mainly to the evolution of whole taxonomic groups over long periods of time.

Speciation

The formation of new and distinct species in the course of evolution.

Mutation

Any change in the DNA sequence of a cell, which may be caused by mistakes during cell division or exposure to DNA-damaging environmental agents.

Artificial Selection

A process in which humans consciously select for or against particular features in organisms (e.g., choosing which individuals to breed or save seeds from).

Natural Selection

A process through which populations change over generations because individuals better suited to their environment survive and reproduce at a higher rate.

Fitness

The ability of an individual to survive and reproduce in its specific environment, reflecting the suitability of an organism or species for reproductive success.

Adaptations

The ability of living organisms to adjust themselves to their surroundings, or changing behavior and traits to suit a new purpose or situation.

Genetic Drift

The change in frequency of an existing gene variant in a population due to random chance, which may cause gene variants to disappear completely and reduce variation.

Bottleneck Effect

Occurs when a population's size is drastically reduced for at least one generation due to natural disasters, habitat loss, or overhunting.

Geographic Isolation

The physical separation of populations of organisms from one another due to geographical barriers, leading to distinct traits and speciation.

Reproductive Isolation

A process occurring when two populations evolve to the point that they cannot interbreed to produce fertile offspring, preventing different species from mating.

Genetically Modified Organisms (GMOs)

Plants, animals, or microbes in which one or more changes have been made to the organism’s genetic material.

Range of Tolerance

The critical maximum and minimum limits of an abiotic variable that an organism can withstand.

Fundamental Niche

The entire set of conditions under which an animal, population, or species can survive and reproduce itself.

Realized Niche

The set of conditions actually used by a given animal, population, or species after interactions like predation and competition are taken into account.

Species Distribution

The manner in which a biological taxon is spatially arranged.

Sympatric Speciation

The evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic region.

Allopatric Speciation

A mode of speciation that occurs when biological populations become geographically isolated from each other to an extent that prevents or interferes with gene flow.

Generalists

Organisms that can eat a variety of foods and thrive in a wide range of habitats.

Specialists

Species that can only thrive in a narrow range of environmental conditions or have a limited diet.

Mass Extinction

An event in which at least half ($50\%$) of all species die out in a relatively short period of time.

Sixth Mass Extinction

An extinction event driven by human activity, primarily through unsustainable land, water, and energy use, as well as climate change.

Background Extinction

Also called the normal extinction rate, it is the natural evolution and elimination of species from the Earth over a long period of time.

Coevolution

The process of reciprocal evolutionary change that occurs between pairs of species or among groups of species as they interact with one another ('evolutionary arms race').

Resource Partitioning

When different organisms within one ecosystem split up an area and resources through special adaptations to avoid direct competition.

Keystone Species

A species that plays a relatively large role in the ecosystem despite not having an unusually large population (e.g., sea otters regulating sea urchin populations).

Indicator Species

An organism that reflects the health of its environment and is often among the first to be affected by changes such as pollution, habitat loss, or climate change.