AP BIO Chapter 15/16 (Clades and Phylogenetic Trees)

Phylogenetic Tree

Diagram reconstruction of the evolutionary history of relationships between organisms

Root

The common ancestor of all the organisms on a phylogenetic tree

Node

When a lineage on a phylogenetic tree splits into two

Taxon

A group of species that we designate with a name

Clade

A taxon that includes the evolutionary descendants of a given ancestor

Systematics

the study of biodiversity

Cladogram

a diagram that does not show common ancestors/evolutionary relationships, instead showing when a given species branched off

Homologous traits

a feature shared by multiple species, that IS inherited from a common ancestor (one bone, two bone, many bone)

Convergent Evolution

a feature shared by multiple species by that developed INDEPENDENTLY (ie: bird wings and bat wings). Analogous

Mutations

Any change in nucleotide sequences, occur randomly and is the cause of natural selection/evolution

Migration

Movement of individuals between populations, the cause of gene flow

Population Bottleneck

An environmental event results in the survival of only a few individuals

Homoplasies

Similar structures in organisms to have a shared way of life (analogous).

Parsimony Principle

the preferred explanation of observed data is the simplest explanation (the one that requires fewest homoplasies)

Nomenclature

Kingdom, Phylum, Class, Order, Family, Genus, Species

Binomial Nomenclature: genus and species name (ie: homo sapiens)

Adaptation

A trait that helps an organism survive and reproduce more efficiently.

Sexual selection (non-random mating)

When individuals of one sex prefer certain traits of the opposite sex more than others (preferential)

Hardy-Weinberg Principle

Equilibrium; allele frequencies do not change across generations.

Taxonomy

The scientific study of how living things are classified

Stabilizing selection

Natural selection that favors intermediate variants by acting against extreme phenotypes

Directional Selection

Natural selection that favors traits in one direction different from the mean

Disruptive selection

Natural selection that favors traits in either direction from the mean (small beak or large beak, not middle)

Muller's ratchet

Asexually reproducing species can accumulate deleterious mutations (ones that increase the likelihood of a certain disease)

Phylogeny

Evolutionary history of a species

Monophyletic

A clade, containing an ancestor and all of their descendants.

Paraphyletic

A group that does not include all of the decendants of the common ancestor

Polyphyletic

A group that does not include the common ancestor of the entire group