Evolution Flashcards
Evolution
the change in the frequency of an allele from one generation to the next
gene
section of DNA that codes for a protein (usually traits)
locus
spot on a chromosome where a gene is found
allele
different form of a gene
genotypes
genetic makeup of an organism
phenotype
expressed traits of an organism
genetic variation
all organisms vary
population/species
a group of individuals that can exchange genetic information
gene pool
-number of alleles
-the larger the gene pool, the larger the genetic variation
population genetics
study of the patterns of genetic information
mutation
changes nucleotide sequences
recombination
crossing over in meiosis
nucleotides
sugar
phosphate
nitrogenous base
gamete
sex cells
2n->2n= mitosis
2n->n=meiosis
germ-line mutation
mutation that occurs in the form of a gamete
somatic mutations
mutations in a cell not producing gametes
deleterious
genetic variations that make it hard to survive and reproduce
neutral
genetic variations that don’t help or hurt
advantageous
genetic variations that help survive and reporduce
adaptation
a genetic change to an individual that makes them better able to survive and reproduce
allele frequencies
of an allele/total # of alleles
Gregor Mendel
did most of his work on peas and looked at seven different traits
fixed allele
100% allele frequency
test cross
crossing with a homozygous recessive to determine the allele frequency
electrophoresis
catalysts
enzymes that bind molecules
Hardy-Weinberg Equilibrium conditions
-no selection (no difference in survival/ reproductive success of individuals)
-no migration or immigration
-no mutation
-mating must be random
Lamark
-the French consider him the father of evolution
-he was looking at evolution in individuals instead of populations
genetic drift
change in allege frequencies due to the random effects of a small population
natural selection
the driving mechanism for how populations change
Darwin’s postulates
- all organisms show variation
- all species produce more offspring than can survive
- individuals with favorable traits will tend to survive and reproduce, passing favorable traits to offspring
- result is a change toward favorable traits in the population
- overtime this leads to populations becoming adaptive to their environment
fitness
a measure of how well an individual’s phenotype is represented in the next generation
artificial selection
differential breeding
stabilizing selection
selects against extremes
directional selection
selects against one of the two extremes
disruptive selection
selects against the mean and favors the extremes
sexual selction
selection that promotes an individuals access to mating
extinction
allele is 0% of the population
genetic bottleneck
-starts with a large population and ends with small population
-allele frequency is altered due to a population crash
-bottlenecked population= founders effect
-starts a new population
-over/under-represented genes
divergence
molecular evolution
molecular clock
using the amount of change between 2 groups to estimate the last time they were together
species
fundamental biological unit
Biological Species Concept (BSC)
-proposed by Ernst Mayer
-a species is a group of interbreeding populations that are reproductively isolated from other groups and have to be able to produce reproductively viable offspring
