Natural Selection
The process by which individuals better adapted to their environment survive and reproduce.
selection
Structures that have lost their original function during evolution.
vestigial
The formation of new species.
speciation
The point where two branches split on a cladogram.
node
Movement of alleles between populations when organisms migrate.
gene flow
A trait that increases survival or reproduction in a specific environment.
adaptation
Structures that are similar in different species because they share a common ancestor.
homologous
When populations become separated by physical barriers like mountains or rivers.
geographic isolation
An organism included in a phylogenetic tree that is less closely related to the others and used for comparison.
outgroup
Random changes in allele frequency due to chance events.
genetic drift
The original source of new genetic variation that natural selection acts on.
Genetic Mutation (close answers accepted)
Comparing developmental similarities among species before birth.
embryology
A theory (explanation) supported by evidence for how populations change over time
Evolution
If two organisms share many derived traits, scientists infer that they share a
recent common ancestor
A few birds from a mainland population are blown to a remote island during a storm. Because only a few individuals start the population, the allele frequencies are very different from the original population.
What evolutionary effect is occurring?
Founder effect
Selection when one extreme phenotype is favored, causing a population to shift in one direction.
Directional
Body parts that share a common function but have a different structure
Analogous
When two populations of birds can no longer reproduce due to different sounding songs, they are considered different species due to
behavioral isolation
Phylogenetic trees are built primarily using similarities in
DNA
Two populations of birds begin to look more genetically similar after individuals start moving between them and interbreeding.
What mechanism is occurring?
Gene flow/migration
Two different species of birds evolve similar beak shapes because they eat the same type of food, even though they are not closely related. What is this pattern called?
Analagous Structures/Convergent Evolution
List the FIVE major pieces of evidence for evolution.
homologous structures, fossil record, DNA/Molecular, Direct observation, and Embryology
A population of insects shows three wing sizes: small, medium, and large. Birds preferentially eat insects with medium-sized wings, leaving small and large-winged insects more likely to survive and reproduce.
What type of natural selection is occurring?
Disruptive
If two species share a more recent common ancestor with each other than with other species on the tree, what are 4 things they may have in common?
Common ancestor, DNA, traits/characteristics, embryos, fossils, etc. (close answers accepted)
Group performance: entire team must list the 5 fingers of evolution together, then one person describe/give an example for how each mechanism causes evolution.
small population, non-random mating, mutations, gene flow, adaptation/natural selection.