Mechanisms of Evolution
This process explains how individuals with advantageous traits are more likely to survive and reproduce.
natural selection
Evolution of similar traits in unrelated species due to similar environments.
convergent evolution
This type of selection favors one extreme of a trait.
directional selection
“Survival of the fittest” actually refers to this, not just physical strength.
being best adapted to the environment
Humans and chimpanzees share approximately this percentage of their DNA.
98-99%
This term describes how well an organism is suited to its environment in terms of survival and reproduction.
Fitness
Similar structures with different functions suggest this evolutionary relationship.
homologous structures
This type of selection favors the average trait and reduces variation
stabilizing selection
True or False: Individuals evolve during their lifetime
False
What reptile is the closest living relative to modern birds?
Crocodile
These are random changes in DNA that introduce new variation into a population
mutations
Comparing DNA sequences between species helps scientists determine this.
genetic (DNA) evidence / molecular evidence
This type of selection favors both extremes of a trait.
disruptive selection
Natural selection acts directly on this, not on genes themselves.
phenotype
Which salamander never leaves the water and retains its gills
axolotl
Random changes in allele frequencies in a population.
genetic drift
Structures that no longer serve a major function provide this kind of evolutionary evidence.
vestigial structures
When environmental conditions change, this happens to the traits that are favored in a population.
change in selective pressure (or environment affects trait selection)
Variation in populations comes from inherited traits and this additional source.
mutations
What continent, known for being icy today, was once home to dinosaurs?
Antarctica
The loss of genetic variation when a new population is established by a small number of individuals.
Founder effect
When multiple species share similar structural patterns, it suggests this about their ancestry.
common ancestry
This explains how selection can lead to changes in the average value of a trait over generations.
evolution of a trait distribution (shift in population mean)
Evolution does not create “perfect” organisms; instead, it results in this.
being well-suited/adapted to the environment (not perfect)
What insect group existed before the dinosa