Speciation & Common Descent

speciation

the formation of new species as a result of evolution

common descent

principle that all living things have a common ancestor

homology

Similarity in characteristics resulting from a shared ancestry.

vestigial

forming a very small remnant of something that was once much larger or more noticeable

isolation

separation of a population into 2 or more groups that cannot interact with each other

biological species concept

Definition of a species as a population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, but are not able to produce viable, fertile offspring with members of other populations.

allopatric

The formation of a new species as a result of an ancestral population's becoming isolated by a geographic barrier.

peripatric

When small groups of individuals break off from the larger group, become geographically isolated, and form a new species. Genetic drift may happen here.

species

A group of similar organisms that can breed and produce fertile offspring.

population

A group of individuals that belong to the same species and live in the same area

reproductive isolation

Separation of species or populations so that they cannot interbreed and produce fertile offspring

bottleneck

A change in allele frequency following a dramatic reduction in the size of a population

founder effect

change in allele frequencies as a result of the migration of a small subgroup of a population

genetic drift

A change in the allele frequency of a population as a result of chance events rather than natural selection.

comparative anatomy (morphology)

the study of similarities and differences in the anatomy of different species

embryology

study of embryos and their development

fossil record

Chronological collection of life's remains in sedimentary rock layers

genetics & biochemistry

study of DNA, RNA, and proteins

biogeography

study of the distribution of organisms around the world

phylogenetics

the study of evolutionary relationships among species

natural selection

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.

cladogram / phylogeny

a branching diagram showing the relationship between a number of species.