Biology 150: Phylogenetics & Speciation

These flashcards cover key vocabulary and concepts related to phylogenetics and speciation from the lecture notes.

Phylogenetic tree

A diagram that shows the evolutionary relationships among various species based on their shared characteristics.

Anagenesis

The gradual evolution of a species through a series of changes that ultimately leads to new forms.

Cladogenesis

The branching evolution that leads to the formation of new species by splitting from a common ancestor.

Monophyletic

A group of organisms that includes an ancestor and all of its descendants.

Polyphyletic

A group of organisms derived from multiple ancestral sources that do not include the most recent common ancestor.

Paraphyletic

A group of organisms that includes an ancestor but not all of its descendants.

Homology

Traits that are similar due to shared ancestry.

Homoplasy

Traits that are similar due to convergent evolution, not shared ancestry.

Synapomorphy

A derived trait shared by a group of organisms that can be used to define a clade.

Speciation

The process by which new species arise from existing species.

Reproductive isolation

The mechanisms that prevent species from interbreeding and producing viable, fertile offspring.

Natural selection

The process by which organisms better adapted to their environment tend to survive and produce more offspring.

Founder effect

Reduced genetic diversity that occurs when a small group of individuals becomes isolated from a larger population.

Allopatric speciation

Speciation that occurs when populations are geographically isolated.

Sympatric speciation

Speciation that occurs within a shared habitat, often through mechanisms like polyploidy or behavioral isolation.

Behavioral isolation

A form of reproductive isolation in which two populations develop differences in courtship rituals or other behaviors.

Gene flow

The transfer of genetic material between populations.

Phenotype

The observable characteristics of an organism, determined by both genetic and environmental factors.

Stabilizing selection

Natural selection that favors intermediate variants by acting against extreme phenotypes.

Fitness

The ability of an organism to survive and reproduce in its environment.