Concepts of Speciation and Evolutionary Biology

Speciation

Process by which new species arise.

Biological species concept

Defines species based on reproductive isolation.

Morphological species concept

Classifies species based on physical traits.

Ecological species concept

Species defined by ecological niche and role.

Phylogenetic species concept

Species defined by evolutionary history and relationships.

Adaptive radiation

Rapid evolution of diverse species from common ancestor.

Sympatric vs. allopatric

Sympatric: same area; Allopatric: different areas.

Species fitness

Ability to survive and reproduce in environment.

Descent with modification

Process where species evolve from common ancestors.

Evolutionary tree

Diagram showing evolutionary relationships among species.

Homologous structures

Anatomical features shared due to common ancestry.

Analogous structures

Similar traits evolved independently in different species.

Coevolution

Mutual evolutionary influence between species.

Outgroup

Group used for comparison in phylogenetic analysis.

Monophyletic

Group containing a common ancestor and all descendants.

Paraphyletic

Group containing a common ancestor but not all descendants.

Sister groups

Two groups that share a most recent common ancestor.

Parsimony

Principle favoring simplest explanation for evolutionary relationships.

Ecological disturbance

Event that disrupts ecosystem structure and function.

Adaptations to disturbance

Changes that enhance survival after ecological disruptions.

Tree adaptations to fire

Features allowing trees to survive and regenerate after fire.

Prescribed fire

Controlled fire used to manage ecosystems and reduce fuel.