Species definitions Flashcards

A group of organisms capable of interbreeding and producing fertile offspring, defined by reproductive barriers, morphological traits, ecological niches, or shared ancestry.

The process where an ancestral species splits into two or more distinct species, often through mechanisms like geographic isolation or reproductive barriers, linking microevolution to macroevolution.

Change in allele frequencies within a population over time, leading to small-scale evolutionary changes without forming new species.

Broad evolutionary changes that occur over long periods, leading to the emergence of new species and higher taxonomic groups, often involving significant morphological, ecological, or genetic shifts.

A variant form of a gene at a specific locus on a chromosome, influencing distinct traits or characteristics in an organism.

Mechanisms preventing different species from mating and producing viable offspring, including prezygotic barriers (e.g., behavioral differences) and postzygotic barriers (e.g., hybrid sterility).

Offspring resulting from the mating of two different species, often sterile or non-viable, exemplifying post-zygotic reproductive barriers.

Mechanisms that prevent different species from mating and forming a zygote, including temporal, habitat, behavioral, mechanical, and gametic isolation.

Mechanisms that prevent hybrid offspring from surviving or reproducing, such as sterility or early death, ensuring that species remain distinct despite interbreeding.

Defines species based on shared physical characteristics, both external and internal, rather than genetic or reproductive differences.

Defines species based on their ecological niche, emphasizing their role and interactions within their environment, suitable for both sexual and asexual organisms.

Defines species as the smallest group of individuals sharing a common ancestor, identified by unique genetic traits on a phylogenetic tree, applicable to both sexual and asexual organisms.

Speciation initiated by geographic isolation, where a population is divided by a physical barrier, leading to genetic divergence and the formation of new species over time.

Speciation occurring within the same geographic area, often driven by factors like disruptive selection or polyploidy, leading to reproductive isolation without physical separation.

A condition where an organism has more than two complete sets of chromosomes due to errors in cell division, leading to genetic variation and potential speciation, especially in plants.