Unit 8 - Evolution - Fill in the Blank

The evolution of one ancestral species into many species adapted to different environments is known as ____________.

Adaptive radiation

Allopatric speciation

____________ occurs when a population is separated by a geographic barrier and eventually forms a new species.

Anagenesis

When one species gradually changes over time into a new form without branching, this process is called ____________.

Artificial Selection

Humans breeding organisms for specific traits is an example of ____________.

Assortative mating

When individuals choose mates with traits similar to their own, it is called ____________.

Autopolyploidy

____________ happens when an organism has extra chromosome sets that all come from the same species.

Biogeography

The study of where species live around the world and why they live there is called ____________.

Bottleneck effect

A sudden drop in population size that reduces genetic variation is known as the ____________.

Cladogenesis

When one species splits into two or more species, the process is called ____________.

Descent with Modification

Darwin used the phrase ____________ to describe how species change over time from ancestral forms.

Directional selection

____________ occurs when natural selection favors one extreme form of a trait.

Diversifying selection

When both extreme forms of a trait are favored over the average, it is called ____________.

Founder effect

The ____________ occurs when a few individuals start a new population with limited genetic diversity.

Frequency-dependent selection

In ____________, the fitness of a phenotype depends on how common or rare it is in the population.

Gene flow

The movement of alleles from one population to another is called ____________.

Genetic Drift

____________ is the random change in allele frequencies, especially in small populations.

Gradualism

The idea that evolution happens slowly and steadily over long periods of time is called ____________.

Hardy-Weinberg Equilibrium

When allele frequencies stay the same from generation to generation, the population is in ____________.

Heterozygote advantage

____________ occurs when individuals with two different alleles have higher fitness than either homozygous group.

Homology/homologous structures

Similar body structures in different species due to shared ancestry are called ____________.

Hox genes/ Homeobox

____________ are genes that help control body plan development in an embryo.

Macroevolution

Large-scale evolutionary change above the species level is known as ____________.

Microevolution

Small changes in allele frequencies within a population are called ____________.

Natural Selection

____________ is the process in which individuals with beneficial traits are more likely to survive and reproduce.

Neutral variation

Genetic differences that do not help or harm survival are called ____________.

Paedomorphosis/neotony

____________ happens when adults keep traits that were previously seen only in juveniles.

Polymorphism

The presence of two or more common forms of a trait in a population is called ____________.

Polyploidy

Having more than two complete sets of chromosomes is called ____________.

Population

A group of individuals of the same species living in the same area is a ____________.

Postzygotic barriers

____________ are reproductive barriers that act after fertilization has occurred.

Prezygotic barriers

Reproductive barriers that prevent fertilization from happening are called ____________.

Punctuated equilibrium

The idea that species stay stable for long periods and then change rapidly is known as ____________.

Sexual dimorphism

____________ refers to differences in appearance between males and females of the same species.

Species

A ____________ is a group of organisms that can mate and produce fertile offspring.

Stabilizing selection

When the average form of a trait is favored and extremes are selected against, it is called ____________.

Sympatric speciation

____________ occurs when new species form in the same geographic area.

Vestigial organs

Structures that have little or no current function but were inherited from ancestors are called ____________.