bacteria just take up DNA from their environment -Main scientist: Griffith (pneumonia experiment) -Others: Avery, McCarty and MacLeod – basically wrote the conclusion to Griffith’s experiment (said that the heat killed pathogenic pneumonia and horizontal gene transfer were responsible for the death of the mice)
Transduction (how bacteria acquire DNA)
a virus (bacteriophage) inserts DNA into the bacteria
Conjugation (how bacteria acquire DNA)
"sexual reproduction" of bacteria
donor gives DNA to recipient via a sex pilus
What does "variation is present before selection" mean?
environment doesn’t cause a change in genetic variation in organisms but rather variation in organisms is present and those individuals are best suited for a changed environment (therefore those organisms would survive and pass on their genes to their offspring).
What did Lamarck propose?
inheritance of acquired characteristics (not entirely correct b/c of obvious reasons)
Examples of genetic variation?
analogous vs homologous structures
analogous: look alike in different lineages but did not evolve in a shared ancestor
homologous: similar body parts reflect shared ancestry
similar organisms in different parts of the world
an organ that was once useful and now has no apparent function
conditions for microevolution
opposite of conditions for hardy-weinberg
Equation(s) for Hardy-Weinberg?
maintains two different alleles b/c each is favored under different conditions
Mimicry (2 kinds)
mullerian-distasteful species look alike
batesian-one tasty organism looks like a distasteful organism
Directional, Stabilizing, Disruptive selection
directional-one end is selected for and the other against
stabilizing-one or both ends are selected against
disruptive-intermediate forms are selected against
What is a species?
organisms that can reproduce and produce viable offspring
splitting of one species into two by one species changing over time to become a new species
Plant Reproduction male vs female parts
Female:stigma (sticky to catch pollen), style, ovary (ovules where meiosis takes place)
Male:Anther (where meiosis takes place), filament
pollen lands stigma, pollen grows a tubule, delivers the sperm nucleus to the ovary
double fertilization-one nuclei fertilizes egg, other nuclei joins with two other cells in ovary to make endosperm