Speciation: Allopatric vs Sympatric

Different species live in different habitats, preventing them from interbreeding.

The concept that groups individuals based on shared physical characteristics, regardless of reproductive potential.

Species reproduce at different times, preventing interbreeding.

The concept that a species is a group of organisms that can interbreed and produce fertile offspring, but are reproductively isolated from other such groups.

Species have distinct mating rituals and behaviors, preventing interbreeding.

The process by which new species evolve from existing ones.

Physical incompatibility of reproductive structures prevents fertilization.

A type of speciation where a population gradually accumulates changes over time, eventually becoming distinct enough to be considered a new species.

A type of speciation where a new species arises from a population that splits off from its parent species.

Sperm and eggs from different species cannot fuse, preventing fertilization.

Hybrid offspring are less likely to survive due to genetic incompatibility.

The concept that groups individuals based on shared physical characteristics, regardless of reproductive potential.

Hybrid offspring are fertile, but their offspring are infertile.

The concept that a species is a group of organisms that can interbreed and produce fertile offspring, but are reproductively isolated from other such groups.

Over generations, hybrid offspring experience a decline in fitness due to genetic mixing.

The process by which new species evolve from existing ones.

A form of speciation where populations become isolated due to a geographical barrier, like a mountain range or a river, leading to the evolution of distinct species over time.

The process where a small, isolated population at the edge of a species' range experiences unique selection pressures and genetic changes, potentially leading to the evolution of a new species.

The evolution of new species due to the founder effect, where a small group of individuals colonizes a new area and diverges from the parent population.

A type of speciation where new species arise from populations that live in the same geographic area but are isolated due to factors like habitat specialization or behavioral differences.

A process where new species arise due to a change in the number of chromosomes within a population, often leading to reproductive isolation and the formation of new species.

The isolation of species through differences in mating preferences or behaviors, contributing to the maintenance of sympatric speciation.

A large lake in Africa home to a remarkable diversity of cichlid fish species that have evolved through sympatric speciation.

A group of closely related fish species found primarily in African lakes, known for their diversity and evolution through sympatric speciation.

A mode of evolution where species experience long periods of stability (stasis) punctuated by rapid bursts of evolutionary change.

A type of evolution where changes in a species occur gradually over long periods.

Evolutionary changes that do not directly impact an organism's fitness.

The theory that all evolutionary change is driven by adaptation to the environment. It argues that any change that does not improve an organism's fitness will not be passed on.

A type of evolution characterized by rapid, significant change that is driven by different factors, often occurring at the edge of a species' geographical range, in response to extreme conditions.

The idea that evolution is not always driven by adaptation, but can also be influenced by random factors, such as genetic drift, that may not necessarily be beneficial.

A theory of evolution that argues that the rate of evolutionary change is not constant and can vary considerably.

Polyploidy occurs more frequently in plants than animals due to the ability of many plants to self-fertilize, making it easier to propagate a new polyploid generation.

Polyploid organisms are unable to reproduce with their diploid parent type, immediately establishing reproductive isolation.

Polyploid organisms often exhibit enhanced vigor, larger size, and are often found in harsh environments.

Many common agricultural plants we rely on were domesticated through polyploidy, including wheat, corn, and rice.

A barrier that stops gene flow without geographic separation.

The process of two species re-merging into one as reproductive isolation breaks down.

When reproductive isolation is incomplete, hybridization (interbreeding) can occur between two species.

The process in which natural selection strengthens reproductive isolation by favoring traits that reduce hybridization.

A hybrid zone where gene flow is maintained, leading to a stable balance between parent species and hybrids.

A hybrid zone that leads to one species absorbing another.

Natural selection that favors traits that reduce hybridization between species.

A situation where two species occupy the same geographic region but do not interbreed due to reproductive isolation.