Unit 2: Classification

Taxonomy

The science of naming and classifying organisms

Taxon (plural: taxa)

A group or level of organization in classification

Taxonomist

A scientist who studies taxonomy

Binomial nomenclature

A two-part scientific naming system (Genus + species)

Domain

The broadest taxon; separates life into Bacteria, Archaea, or Eukarya

Hybrid

Offspring of two different species (e.g., liger, wolf-dog)

Amniotes

Animals whose embryos are protected by an amniotic sac (reptiles, birds, mammals)

Phylogeny

The evolutionary history of a group of organisms

Cladogram

A diagram showing evolutionary relationships based on shared traits

Phylogenetic tree

A diagram similar to a cladogram, but also includes time or genetic differences

Node

A point on a cladogram/phylogenetic tree where a common ancestor is represented

Common ancestor

An ancestral species shared by two or more groups

Evolution

Change in living things over time

Natural selection

Darwin's mechanism for evolution; individuals with advantageous traits survive and reproduce more successfully

Adaptation

A trait that helps an organism survive and reproduce in a specific environment