Phylogenic trees

Adaptive radiation

Occurs when a single lineage rapidly diversifies into multiple species, typically in response to ecological opportunities or key innovations.

Key adaptations

Evolutionary traits that enhance the survival and reproduction of a species in a particular environment (e.g., flight in birds).

Primordial Soup Hypothesis

The theory that life originated from a mixture of organic molecules in the early Earth’s oceans, as demonstrated by the Miller-Urey experiment.

Panspermia

The theory that organic molecules or life arrived on Earth via meteorites.

Protobionts

Membrane-bound structures with basic metabolic activity, considered precursors to cells.

Exaptation

A trait evolved for one function that later adapts for another function, such as feathers originally evolving for insulation.

Clade

A group of organisms that contains a common ancestor and all its descendants.

Phylogenetic tree

A diagram that shows the evolutionary relationships among a group of organisms.

rRNA genes

Highly conserved genes used to study deep evolutionary relationships among organisms.

Hox genes

Developmental genes that control the body plans of organisms and drive evolutionary changes.

Mass extinctions

Events that eliminate many species, leading to periods of adaptive radiation as surviving species exploit available niches.

Geographic isolation

A condition that can promote adaptive radiation, exemplified by Darwin’s finches in the Galápagos.

Self-replicating molecules

Molecules capable of making copies of themselves, like RNA, which likely played a role in the development of life.

Monophyletic group

A clade that includes an ancestor and all its descendants.

Adaptive radiation conditions

Conditions that facilitate adaptive radiation include availability of unoccupied niches, evolution of key adaptations, reduction of competition, and geographic isolation.

Shared derived character

A trait that is unique to a clade and not found in other groups.

Shared ancestral character

A trait found in both the ancestor and its descendants.

Outgroup

A related group used as a reference in phylogenetic studies.

Miller-Urey experiment

An experiment that simulated early Earth conditions and produced organic molecules, supporting the primordial soup hypothesis.

mtDNA

Mitochondrial DNA that mutates faster than nuclear DNA, making it useful for studying recent evolutionary events.