Evolution Review Flashcards
Allele
one variant of a gene (dif. sequence of nucleotides)
Genotype
the alleles that an individual has for a given gene (at a given locus)
Phenotype
An observable trait of an organism
- results from genes & enviro
Microevolution
change in allele frequencies over time within a population (typically gradual)
Macroevolution
- the evolution of new taxonomic groups
- above the species level
Is height increase in humans overtime from improved diet an example of evolution?
No.
Can there be evolution without genetic variation
No
What causes mutations
- errors in DNA replication
- environmental damage (ex. from UV)
Single nucleotide polymorphisms
SNPs
-single nucleotide replacement
-very common
mutations are…?
- usually bad for fitness
- necessary for evolution (because they introduce genetic variance)
- also are very, very rare
- unable to cause evolution on their own
Natural Selection
- differential reproductive success of individuals with different phenotypes
Fitness
- the ‘fit’ to an environment
- organisms ability to pass on its genes in an environment
Natural Selection generates evolution if 3 things are true
- individuals vary in phenotype
- Individuals with different phenotypes have (on average) different reproductive success
(This is the natural selection part) - Phenotypic variation is heritable
adaptations
phenotypes that make their bearers better fit to their environment
- caused by evolution by natural selection
- ex. darwin’s finches
skin / hair / eye pigmentation
a human adaptation associated with latitude
- low latitudes (protection from folate damage from sun)
- high altitudes : need to synthesize vitamin D
Genetic Drift
another mechanism of evolution
Changes in allele frequency in a population due to chance
Bottleneck effect
a form of genetic drift
- drastic reduction in a population… results in changes in allele frequency
gene flow
another mechanism of evolution
The transfer of genetic material from one population to another, through migration
Mechanisms of evolution
Natural Selection
Genetic Drift
Gene Flow
