Natural Selection/Evolution Flashcards
Three word definition of evolution
Change over time
What is artificial selection?
When something other than nature breeds for a selected trait
(ex. dog breeds)
Does the inheritance of acquired traits occur?
NO!
Describe natural selection
Some individuals of a population or species are better suited, to survive and have more offspring.
The ability of an organism to survive and reproduce
Fitness
What does natural selection work upon?
PHENOTYPES
All of the different alleles for all the genes in a population
Gene pool
What type of trait has the most variability?
Polygenic traits
If an allele makes up a third of the the alleles for that particular gene in a gene pool, what is its relative frequency?
33%
List and describe the five factors that would cause evolution to occur in a population.
- Small population size - the population shrinks and the decreased number makes up the new gene pool
- Non-random mating - mates are chosen based on location or desired traits
- Mutation - any change in the DNA sequence
- Movement (gene flow) - immigration or emigration (movement of an organism into or out of a population)
- Adaptation - a trait that makes an organism more likely to survive and reproduce
What are the five conditions required for genetic equilibrium?
- Large population
- Random mating
- NO mutation
- NO movement
- NO adaptations
The two main sources of genetic variation are ______ and _______; which is more common?
mutation and gene shuffling
gene shuffling is more common
What is genetic drift?
A RANDOM change in the allele frequency of a population
Any time there is a change in the allele frequency, then _______ has occured.
Evolution
Which type of natural selection is represented in the graph?
Stabilizing selection
Which type of natural selection is represented in the graph?
Diversifying Selection
What type of natural selection is represented in the graph?
Directional Selection
The type of natural selection that selects against the extreme versions of a trait.
Stabilizing selection
When the entire population’s traits move towards one particular version of the trait
Directional selection
The only type of natural selection that can lead to speciation
Diversifying (disruptive) selection
The idea that evolution occurs gradually over a long period of time
Gradualism
What is punctuated equilibrium?
The idea that evolution occurs with periods of rapid change which are separated by periods of little or no change
A type of adaptation that allows organisms to blend in with their environment
Camouflage
What is warning coloration?
Organisms have coloration that signify their danger (usually toxicity)
Organisms are lightly colored on their underside so that they are not seen as well by predators/prey
Counter shading
Describe mimicry.
When an organism copies the appearance of another species
Compare and contrast analogous and homologous structures.
Analogous structures - different structures that have the same function
Homologous structures - body parts that have the same structure in different animals but that carry out different functions
A tool in science that is used to show common traits among organisms, how organisms are related, and common ancestors among different organisms.
Cladogram
A type of isolation where organisms are separated by things such as rivers, mountains, or oceans
Geographic isolation
The accumulation of differences between groups is called
Divergence (divergent evolution)
