Biology 221 – Albright Lecture Exam 1 Study Guide

Vocabulary flashcards covering key concepts from biology related to evolution and natural selection.

Chromosome fusion

A type of genetic change where two chromosomes combine to form a single chromosome.

Translocation

A genetic change involving the transfer of a segment of one chromosome to another chromosome.

Transposable elements

DNA sequences that can change their position within the genome, potentially altering gene expression.

Epigenetics

Changes in gene expression that do not involve alterations to the underlying DNA sequence.

Homeotic (HOX) genes

Genes that determine the body plan and structure during development in animals.

Natural selection

The process by which individuals with favorable traits are more likely to survive and reproduce.

Hardy-Weinberg Equilibrium

A principle stating that allele frequencies in a population will remain constant in the absence of evolutionary influences.

Genetic drift

Random fluctuations in allele frequencies in a population, leading to evolutionary change.

Stabilizing selection

A type of selection that favors intermediate phenotypes over extremes.

Directional selection

A type of selection that favors one extreme phenotype over the other.

Disruptive selection

A type of selection that favors both extreme phenotypes over intermediate phenotypes.

Prezygotic and postzygotic isolation reproductive barriers

Factors that prevent fertilization from occurring between species.

Postzygotic reproductive barriers

Factors that reduce viability or reproductive success after fertilization has occurred.

Allopatric speciation

Speciation that occurs when populations are geographically isolated.

Sympatric speciation

Speciation that occurs when populations are in the same geographic area but diverge due to other factors.

Homologous structures

Anatomical features in different species that share a common ancestry.

Analogous structures

Structures in different species that serve similar functions but do not share a common ancestry.

Adaptive radiation

The process by which a single ancestral species rapidly diversifies into a range of forms adapted to different environments.

Heterochrony

An evolutionary change in the timing or rate of developmental events.

Paedomorphosis

The retention of juvenile traits in the adult stage of an organism.