Exam One Flashcards
Define evolution
The change in genetic composition of populations over time
Define evolutionary theory
Large body of accumulated science on what evolutionary changes have occurred and how they occur
What are the three principles of Darwin’s theory?
- ) Species change over time
- ) Divergent species share a common ancestor
- ) The change in species can be explained by natural selection
Define natural selection
Increased survival and reproduction of some individuals compared with others due to preferable traits
Define population
Group of individuals of a single species that live and interbreed in a particular geographic area at the same time
Fill in the blank:
Individuals do not evolve; ________ do.
Populations
What are the five processes for evolution?
- ) Mutations
- ) Selection
- ) Gene flow
- ) Genetic drift
- ) Non-random mating
Define mutation
Change in sequence of organism’s DNA
Are mutations helpful, harmful, or random in that sense?
Random
Define adaptation
- ) Favored trait that evolves through natural selection
2. ) The process of evolving favored traits
What is the difference between stabilizing, directional, and disruptive selection?
Stabilizing favors average individuals.
Directional favors one extreme.
Disruptive favors both extremes.
Define genetic drift
Random changes in allele frequencies in generations
When is genetic drift most likely to occur?
Smaller populations as a result of “population bottlenecks”
Define founder effect
Small number of individuals colonize new area; unlikely to include all genetic variation of source population
Why does non-random mating affect allele frequencies?
- ) An organism that survives but fails to reproduce makes no contribution to the next generation.
- ) Traits evolved to appeal to non-random mating can harm chances of survival (i.e. bright feathers can be appealing to mates but also predators)
How is evolution measured?
Changes in allele/genotype frequencies over time
Define Hardy-Weinberg equilibrium
Purely theoretical situation where evolution does not occur
- ) No mutation
- ) No selection among genotypes
- ) No gene flow
- ) Huge population size
- ) Mating is random
Define genome
Complete DNA sequence
Define phylogeny
Evolutionary history of organisms
Define phlyogenetic tree
Diagram of evolutionary history organized by lineage
Define ancestral trait and derived trait
Ancestral trait: initial condition
Derived trait: new condition
Define morphology
Physical characteristics
Define paleontology
Study of fossils
Define molecular data
DNA, genome
Define species
- ) Groups of organisms that mate with one or another
- ) Groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups
Define reproductive isolation
Situation where two groups of organisms cannot exchange genes
Define taxonomy and systemics
Science of classifying and naming species
Define habitat partitioning
Speciation dependent on fulfilling survival/reproductive niche (i.e. birds that become separate in diet and their abilities to fulfill their dietary needs)
What are the limitations of hybridization?
- ) Mechanical isolation: reproductive organs are physically incompatible
- ) Temporal isolation: species have different mating seasons, so are partitioned in time
- ) Behavioral isolation: rejection or failure to recognize individuals of other species as mating partners.