Exam 1 Flashcards
What is the definition of evolution?
A change in allele frequencies over time.
This encompasses how populations change genetically across generations.
What is a population?
A group of actually and potential mating individuals of the same species.
Define gene.
Segments of DNA that codes for a trait.
What are alleles?
Different versions of a gene.
What is genotype?
Genetic code difference.
What does phenotype refer to?
Displayed differences/varieties.
What is a dominant trait?
The trait more likely to be expressed.
What is a recessive trait?
The trait less likely to be expressed.
What does homozygous mean?
XX, xx.
What does heterozygous mean?
Xx.
Define polymorphism.
Two or more phenotypes (and thus genotypes) in a population.
What is a mutation?
A random change in genotypes.
What is silent mutation?
Nothing changes.
What is missense mutation?
Codes for a different amino acid and protein.
What is nonsense mutation?
Stop codon.
What is non-random mating?
Mating with selection either by individuals.
What is positive assortative mating?
Choosing to mate with individuals similar to you.
What is negative assortative mating?
Choosing to mate with an individual dissimilar to you.
Define drift in evolutionary terms.
A change in allele frequency.
What is the founder effect?
Small pool of genetic information due to a small population leaving/being separated from the main group.
What is the bottleneck effect?
Natural disasters or other events occur which decimate the population.
What is natural selection?
The favoring of a trait with survival and reproductive benefits.
What is stabilizing selection?
Heterozygous traits favored over either extreme.
What is disruptive selection?
Both extremes are favored over the heterozygous version.
What is directional selection?
One extreme is favored.
Define variation.
Differences in traits.
What is heritability?
How much a trait’s variability in a population is due to genetics.
What is differential reproductive success?
The different rates of success an individual has to reproduce based on successful traits.
What is artificial selection?
Selection that occurs outside of natural selection, typically acted on by humans.
What is speciation?
The process by which species diverge.
Define biological species concept.
Species are individuals that can breed and produce viable offspring.
What is the evolutionary species concept?
Species are a lineage of organisms with a distinct evolutionary trajectory.
What is the ecological species concept?
Species are groups of organisms that share a common ecological niche.
What is anagenesis?
A population changes as a whole.
What is cladogenesis?
A population splits into two or more populations.
What are reproductive isolating mechanisms?
Mechanisms that prevent gene flow between populations.
Define allopatric speciation.
Speciation occurs when a population is separated by a geographical boundary.
What is peripatric speciation?
Speciation occurs when a small group of individuals breaks off from the original community.
What is parapatric speciation?
Speciation occurs without a solid boundary and populations can still intermix.
Define sympatric speciation.
Speciation occurs within the former population.
What is a cladogram?
Graphical representation of the branching sequence of evolution.
What is a primitive trait?
Inherited trait from a common ancestor that is still retained.
What is a derived trait?
Traits that occurred via mutation in a most recent ancestor.
What does homologous mean?
Traits that are shared among organisms due to a shared common ancestor.
What does analogous mean?
Traits that are shared among organisms due to a shared niche.
What is taxonomy?
Science of classifying and organizing organisms.
What is a taxon?
Group of organisms of any rank.
What is a holotype?
The example organism that is used to describe and represent its species.
Define apomorphy.
Unique/derived, non-primitive traits, unique to a lineage.
What is synapomorphy?
Shared derived traits.
What is plesiomorphy?
Primitive, retained traits.
What is symplesiomorphy?
Shared primitive traits.
Define phylogeny.
Evolutionary history and relationship among individuals or groups of species.
What is phenetics?
Grouping based on overall similarities.
What is paraphyly?
Branches of organisms grouped based on perceived similarities.
What is polyphyly?
Branches grouped based on a shared recent common ancestor minus one or more.
What is monophyly?
Branches grouped based on their shared most recent common ancestor.
What does parsimony refer to in evolutionary biology?
The least amount of changes needed to explain the acquisition of a trait.
What is the last common ancestor?
The most recent common ancestor between clades of organisms.
