AP Biology Evolution 7A and 7B

equilibrium

allele and genotype frequencies remain constant

conditions of hardy weinberg principle

no mutations, random mating, no natural selection, extremely large population size, no gene flow

if any condition of hardy weinberg is not met then...

population is evolving

random mating

opposite of sexual selection (females choose partners for a reason)

why is a large population size important for equilibrium?

smaller populations have more likely chance of evolution occurring by chance

what is gene flow

immigration, emigration

allele frequencies formula

p+q=1

genotype frequencies formula

p^2+2pq+q^2=1

causes of evolution

mutations, nonrandom mating, natural selection, genetic drift, gene flow

natural selection

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.

disuse (Lamarck)

organisms lost parts because they didn't use them

use and need (Lamarck)

constant use of organ leads to increase in size

endemic

native to area

adaptive radiation

rapid speciation, new species filling new niches because they inherited successful adaptations

Very Old Cats Always Fear Dogs

variation, over-production of offspring, competition, adaptations, fitness, descent with modification

variation

differences allowing members to successfully compete, feed, reproduce, pass traits onto offspring

over-production of offspring

more offspring than environment can support

competition

biotic (living) and abiotic (nonliving) factors

fitness

the ability to survive, reproduce, pass on a gene

mutation

change in DNA sequence, may or may not affect phenotype

microevolution

change in the allele frequencies of a population over generations

evolution is based on

genetic variation

sources of genetic variations

point mutations, chromosomal mutations, sexual recombination

point mutations

changes in one base (sickle cell anemia)

chromosomal mutations

delete, duplicate, disrupt, rearrange, these are harmful (nondisjunction)

sexual recombination *

contributes to most genetic variation in a population: crossing over, independent assortment of chromosomes, random fertilization

population

group of individuals that live in the same area and interbreed to produce fertile offspring

species

can mate, have fertile offspring

gene pool

all of the alleles for all genes in all the members of the population

fixed allele

all members of a population only have 1 allele for a particular trait

genetic drift

small populations have greater chance of fluctuations in allele frequencies

founder effect

few individuals isolated from larger population

bottleneck effect

sudden change in environment drastically reduces population size

evidence for evolution

direct observations, fossil record, homology, biogeography

MRSA

antibiotic resistant bacteria, from mutations

homologous structures

similar anatomy from common ancestors

absolute / radiometric dating

uses half-life, radioactive isotopes, figure out age of rock

relative dating

shows most primitive (oldest) fossil based on layers

fossils only from in

sedimentary rock

homology

characteristics in related species can have underlying similarity even though functions may differ

embryonic homologies

similar early development (vertebrate embryos)

vestigial organs

structures with little or no use (flightless bird wings on ostriches)

molecular homologies

similar DNA and amino acid sequences

greatest evidence for evolution

DNA

convergent evolution

distantly related species resembling one another (analogous structures)

analogous structures

similar structures, function in similar environments

endemic species

found at a certain geographic location and nowhere else, ex: marine iguanas at Galapagos islands

macroevolution

broad pattern of evolution above the species level

hybrid

offspring or interspecific mating

reproductive isolation

Separation of species or populations so that they cannot interbreed and produce fertile offspring

only way to count two separate species

reproductive isolation

prezygotic barriers

prevent mating or fertilization between species (prevent sperm and egg uniting)

5 prezygotic barriers

habitat isolation, temporal (timing), behavioral (ex: having a mating song), mechanical (parts don't fit together anymore), gametic (sperm cannot fertilize)

post zygotic barriers

prevent the hybrid zygote from developing into a viable, fertile adult

3 post zygotic barriers

reduced hybrid viability (health issues), reduced hybrid fertility (infertility), hybrid breakdown (1st gen is okay, 2nd gen starts breaking down)

2 types of speciation

allopatric and sympatric

allopatric speciation

a population is divided by a geographic barrier, impeding gene flow (ex: river, mountain)

which regions tend to have more species

isolated and subdivided (rather than similar and undivided)

sympatric speciation

speciation happens when populations still live in the same geographic area (examples: sexual selection, polyploidy)

gradualism

evolution occurs slowly over hundreds of thousands of millions of years

punctuated equilibrium

evolution occurs after long period of stasis (equilibrium)

divergent evolution

occurs when adaptation to new habitats results in phenotypic diversifications

speciation rates are rapid during

times of adaptive radiation

horizontal gene transfer

transfer of genes between cells of the same generation, also called lateral gene transfer

3 processes of horizontal gene transfer

conjugation, transformation, transduction

conjugation

plasmids, direct cell-to-cell contact

transformation

bacteria take up extracellular info. and takes them into genomes (recombination)

transduction

bacteria injects previous hosts dna into new host

horizontal gene transfer leads to

genetic diversity

how did life arise

synthesis of amino acids/nitrogenous bases --> macromolecules --> protocells --> self-replicating molecules

RNA world hypothesis

1st genetic material was most likely RNA

protocells

membrane-containing droplets, most primitive cells

first catalysts

ribozymes (RNA)

opaline and haldane

primitive soup (the synthesis of organic compounds) with energy from lightning and UV radiation

miller and urey

tested opaline-haldane, produced amino acids with experiment using electrodes

lipid-membrane hypothesis

Lipid molecules spontaneously form membrane-enclosed spheres "liposomes" which could have led to early cells.

sedimentary rock can show what layers

mineralized, organic, incomplete record

first fossils formed how long ago

3.5 billion years ago

half life

of years for 50% of original sample to decay

endosymbiont theory

mitochondria and chloroplasts formed from small prokaryotes living in larger cells

evidence of endosymbiotic theory

replication by binary fission, single circular DNA, ribosomes to make proteins, enzymes similar to living prokaryotes, two membranes (endocytosis, engulfing)

major periods end with

mass extinctions

new periods begin with

adaptive radiations

evo-devo

evolutionary and developmental biology

homeotic genes

master regulatory genes determine location and organization of body parts

tools used to determine evolutionary relationships

fossils, morphology, molecular evidence

taxonomy

classifying and naming organisms

Dying King Phillip Cried Out For Goodness Sake

domain, kingdom, phylum, class, order, family, genus, species

each category at any level is called a

taxon

binomial nomenclature

Genus species

difference between bacteria and archaea

bacteria: cell wall of peptidoglycine, archaea: cell wall not made up of peptidoglycine, live in extreme environments

branch point / node

where lineages diverge, a common ancestor

sister taxa

groups that share an immediate common ancestor

branch lengths can represent

genetic change and time

shared derived characteristics

evolutionary novelties, used to construct cladograms

most common clade groups

monophyletic groups

principle of maximum parsimony

use simplest explanation (fewest DNA changes) to construct phylogenetic tree

molecular clocks

measure evolutionary change based on regions of genome that appear to evolve at constant rates

3 domains

bacteria, archaea, eukarya

common ancestry of all life forms is proven by (3 things)

DNA and RNA are carriers of genetic info, universal genetic code, conserved metabolic pathways (glycolysis)