Evolution and Phylogeny Flashcards

Flashcards covering key concepts in evolution, phylogeny, and genetics based on lecture notes.

Evolution

The change in the inherited traits of populations of organisms over many generations. Descent with inherited modification.

Phylogeny

Family tree; evolutionary history of a species or group of organisms.

Clade

A grouping that includes a common ancestor and all the descendants (living and extinct) of that ancestor.

Archaea

Single-celled organisms that lack a nucleus and other membrane-bound organelles, similar to bacteria but have unique biochemical and genetic characteristics.

Bacteria

Comprise single-celled prokaryotes lacking a nucleus or other membrane-bound organelles, but with different genetic and biochemical traits than Archaea.

Eukarya

All organisms whose cells have a nucleus and other membrane-bound organelles; includes plants, animals, fungi, and protists.

Phylogenetic Trees

Constructed by analyzing shared characteristics (primarily DNA and protein sequences) to determine how closely related organisms are.

Taxon

Represents the evolutionary relationships among a set of organisms (group of organisms) called taxa (singular: taxon).

Common Ancestor (Phylogenetic Tree)

Nodes of the tree represent the common ancestors of descendants.

Sister Groups

Two descendants that split from the same node.

Outgroup

Taxon outside the group of interest.

Phylogeny (Actual)

The actual evolutionary history/relationships among species or groups of organisms; a concept or hypothesis, not a diagram.

Evolutionary Tree

General term for any branching diagram that represents evolutionary relationships.

Phylogenetic Tree (Diagram)

Diagram that represents a hypothesis about the evolutionary relationships among organisms.

Cladogram

Type of phylogenetic tree that shows only the branching order/relationships, not time or amount of change.

Common Ancestor

An ancestral organism shared by two or more groups of organisms.

Analogies

Traits that have similar functions but evolved independently due to convergent evolution.

Divergent Evolution

When two or more species evolve from a common ancestor, becoming more different over time.

Convergent Evolution

When unrelated species evolve similar traits independently, often due to similar environmental pressures.

Phylogenetic Systematics

Use shared ancestry as the basis for classification; incorporate molecular/morphological evidence.

Mutation

are changes in an organism's DNA sequence; they are the source of new genetic variation, providing the raw material for evolution.

Migration/Gene Flow

The transfer of genetic information between populations; it occurs when individuals move from one population to another and reproduce there, or when gametes like pollen are transported between populations.

Genetic Drift

Is a random change in allele frequencies due to chance events, particularly in small populations.

Natural Selection

Individuals with traits that make them better adapted to their environment are more likely to survive and reproduce; these advantageous traits are passed on to the next generation, leading to an increase in the frequency of those traits in the population.