biology: principles of evolution Flashcards
what did darwin discover
finches where each species was descendent from ancestral finch
different finch species have differently shaped beaks that are best adapted for different foods
who was darwin?
ships naturalist on HMS beagle
travelled to galapogos islandsand South America to study animals
darwins famous theory
descent with modification
due to natural selection
four parts to Darwin’s theory of natural selection
overproduction
genetic variation
struggle to survive
differential reproduction
overproduction
populations ,multiply
then exceed resources
genetic variation
individuals vary in population
struggle to survive
resources are limited; best adapted individuals compete and survive
differential reproduction
fittest individual survive
gets to pass best adaptations onto offspring
fitness
measure of individuals hereditary contribution to next generation
hat is the evidence for evolution
fossil record biogeography anatomy and embryology biological molecules direct observation of evolutionary change
fossil record
veal existence of extinct species
oldest fossils are fish to amphibians to reptiles to mammals and birds
principle of superposition
fossils in deeper soil= older/primitive
fossils close to surface: younger/ advanced
relative age
:age compared to other fossils
absolute age
age estimated from radioactive dating
Biogeography
Species distribution makes no sense unless they arose from common ancestor
Homologous structures
Similar characteristics resulting from common anscestry
Analogous structure
Similar characteristics due to summon envirnment
Vestigial organs
Remnants of structures important to anscestors but not current organisms
Embryonic homologies
Similar stages of development among related species
Biological molecules
All living things share same genetic code( DNA &RNA)
Direct observation of evolutionary change
Drug resistant viruses and antibiotic resistant bacteria
Population genetics
Study of evolution from a genetic standpoint by assessing the gene pool
Utilizes study of micro evolution
Gene pool
Total genetic information available in population
Population
Group of individuals of same species that routinely interbreed
Fitness
Ability of an organism to produce fertile offspring
Micro evolution
Generation to generation change in populations gene frequency
Gene
Piece of DNA coding for phenotype
Phenotype frequency
Percentage of individuals with particular phenotype in population
Gene frequency
Percent of gene copies in a population for a given trait
Change in gene frequency can indicate evolution is occurring
Macro evolution
Changes In Species over geologic time
Genetic drift
Random process that affects genetic make up of a population
Natural selection
A process that allows organisms with a genotype better fit for the environment tend to survive and reproduce more
How is genetic variation produced?
Mutation
Sexual reproduction
Hardy-weinburg conditions for non-evolving population (genetic equilibrium)
No mutation No migration Very large population size Rwandan mating No naturals selection
Under what conditions will population evolve?
Mutation
Migration/gene flow
Genetic drift in small population
Mutations
Introduce new genes that may provide a selective advantage
Migration/ gene flow
Genes move from one population to another
Mix during sexual reproduction
Immigration/emigration
Genetic drift in a small population
Random increase or decrease of genes is strong in small population
Founder effect
Gene frequencies in small migrating group not same as original population
Bottleneck effect
Population undergoes dramatic decrease in size
Smaller population unlikely to represent makeup of original population
Non-random mating/ sexual selection
Leads to differences in appearance of males and females
Females
Big energy investment in offspring: increase fitness by choosing superior mate
Males
Little energy investment in offspring: increase fitness by increasing quantity of offspring
Natural selection
Acts upon phenotypes
Stabilizing selection
Favors most common trait because best adapted (in the middle)
Disruptive selection
Favors both extremes of phenotypic range (both ends none in middle)
Directional selection
Favors traits that are on one extreme of phenotypic range (shift to one side)
