AP Bio Semester 1: Units 1, 2, 3, 8, 9

null hypothesis

states that there is no difference between the two conditions; data either rejects or fails to reject based on chi-squared analysis

chi-squared analysis

compares differences between expected results and experimental; value > critical value = rejects null; critical value based of df and p

error bars

±2SEM (standard error of the mean); overlap = data sets are statistically the same

stimulus

activates behavior

response

behavior prompted by stimulus

innate behavior

developmentally fixed and nearly the same in every individual within a species

fixed action patterns

innate behaviors that are caused by an external stimulus

communication

transmission and reception of signals between animals

signals

stimulus transmitted from one organism to another

proximate causation

how a behavior occurs or is modified

ultimate causation

why a behavior occurs during natural selection

learned behavior

modified as a result of specific experiences

spatial learning

ability to learn and remember the layout of the environment to find resources

associative learning

organism learns to connect two stimuli, or a stimulus with a response, to anticipate future events

altruistic behavior

reduce an animal's individual fitness but increase the fitness of other individuals in the species

inclusive fitness

total effect an individual has on proliferating his genes

population

a group of the same species living in the same area

abiotic factors

nonliving factors which impact population distribution

biotic factors

living factors which impact population distribution

intrinsic factors

factors within the population which impact distribution

community

all the populations in a specific area

symbiosis

interspecific interactions - mutualism, herbivory, parasitism, predation

mutualism

mutually beneficial species interaction

herbivory

consumption of plant material by animals

parasitism

individual organism consumes nutrients from another organism

predation

one organism kills and consumes another

commensalism

one organism benefits while there's no impact on the other

selective advantage

traits help organism to survive or reproduce

coevolution

cases where two (or more) species reciprocally affect each other's evolution

keystone species

species with an influential and regulatory role in the community; maintains/increases biodiversity + controls population size

invasive species

nonnative species that outcompetes native species for resources because of lack of natural predators

primary succession

An ecological succession that begins in an area where no biotic community previously existed

secondary succession

succession on destroyed climax/intermediate community impacted by disturbance

nitrogen cycle

nitrogen fixing bacteria --> plants, herbivores, and carnivores --> denitrifying bacteria/build proteins, DNA, and RNA

carbon cycle

CO2 in atmosphere is broken down by all living things, cell respiration returns to atmosphere + decomposition of dead organisms

k selection (type I)

organisms that don't produce much offspring, but have long lifespans

r selection (type III)

organisms that produce lots of offspring with low lifespans

density dependent factors

limiting factors that affect per capita growth rate with change to density (competition, predation, disease)

density independent factors

limiting factors that affect per capital growth rate without change to density (natural disasters)

extinction vortex

small pop --> loss of genetic variability --> reduction in individual fitness and population adaptability --> smaller pop

evolutionary success

organism lives to survive and reproduce; anything that helps get DNA into the future

darwin's theory of evolution

variation in population --> over production of offspring

--> competition for limited resources --> some members' variation help them survive

differential reproduction

individuals who survive pass adaptations to the offspring

evolutionary fitness

individuals with certain phenotypes leave behind more surviving offspring --> the population changes over time

origin of life hypotheses

1 - replication first (RNA = first molecule)

2 - metabolism first (reverse krebs cycle)

Miller Urey experiment

nonliving materials + early atmospheric conditions, low temperatures, UV lightning = amino acids (biomolecules)

key earth events

life originated --> oxygen accumulated --> 1st eukaryotes --> endosymbiosis --> animals --> cambrian explosion --> colonization of land --> early mammal evolution

hardy-weinberg equation

p + q = 1

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

hardy-weinberg principle

allele frequencies in a population will remain constant at genetic equilibrium (no evolution) unless some factors cause them to change (evolution)

evolution

change in gene pool over time; microevolution --> macroevolution --> speciation

genetic drift

A change in the allele frequency of a population as a result of chance events rather than natural selection.

bottleneck effect

population randomly becomes very small and evolves

founder effect

small population moves to a new place and evolves individually

sexual selection

certain traits make an individual more desirable, and are passed on during reproduction

mutation

random chance adds a new allele/genotype to the population

gene flow

individuals from another population arrive and add to the gene pool

natural selection

certain traits have a selection advantage, making an individual more likely to survive and reproduce

5 mechanisms of evolution

genetic drift, sexual selection, mutation, natural selection, gene flow

biological species

population whose members can reproduce and produce viable, fertile offspring

allopatric isolation

geographic isolation

sympatric isolation

reproductive isolation

pre zygotic isolating mechanisms

geographic, ecological, temporal, behavioral, mechanical, gametic

post zygotic isolating mechanisms

hybrid breakdown, reduced hybrid fertility, reduced hybrid fertility

adaptive radiation

a rapid increase in the number of species with a common ancestor

mutagen

a physical or chemical agent that causes a genetic mutation

phospholipids

make up all cell membranes; tails = non polar carbon chains, heads = phosphate groups, polar

mitosis

cell division which results in 2 genetically identical cells

cell cycle

interphase (G1, S, G2), prophase, metaphase, anaphase, telophase/cytokinesis

p53 protein

stops cell division and calls in repair enzymes

cdk-cyclin complex

mitosis promoting factor that phosphorylates proteins required to drive the cell cycle forward

Rb (retinoblastoma protein)

ensures cells do not enter S phase without the growth factor; growth factor activates cdk-cyclin, which phosphorylates Rb and inhibits its function

stimulator proteins

come from proto-oncogenes, promote cell division

EX - APC (anaphase promoting complex)

suppressor proteins

come from tumor suppressor genes, stop cell division

EX - Rb

cancer

uncontrolled cell division; requires 6 key mutations; turn on growth factors, turn off apoptosis and p53

meiosis

sexual reproduction; cell division which creates gametes (sex cells) -- offspring different from parents

reduction division

chromosomes reduced in half (2n --> 1n) during meiosis 1

meiosis creates variation

independent assortment of chromosomes (metaphase I)

random fertilization

crossing over (metaphase I)

meiosis 1

separates homologous pairs, reduction of chromosomes

meiosis 2

separates sister chromatids (similar to mitosis)

nondisjunction

error in meiosis in which homologous chromosomes fail to separate

polygenic

trait controlled by two or more genes

incomplete dominance

situation in which one allele is not completely dominant over another allele (A + a = mixed A and a phenotype)

codominance

a condition in which neither of two alleles of a gene is dominant or recessive (A + a = both A and a phenotype)

multiple alleles

three or more forms of a gene that code for a single trait (blood types)

epistasis

a type of gene interaction in which one gene alters the phenotypic effects of another gene that is independently inherited

rules of genetics

come in pairs

principle of dominance

principle of segregation

principle of independent assortment

recombinant offspring

phenotype different from either parent

meselson and stahl's experiment

found that DNA is semi-conservative

DNA replication

occurs during S-phase

1 - unwind DNA

2 - start to build new strand

3 - adding more DNA nucleotides

4 - fixing the DNA

okazaki fragments

occur on lagging DNA strand because DNA polymerase III can only build from the 5' --> 3' end

central dogma of biology

DNA (gene) --> RNA --> protein

transcription

RNA polymerase (transcription factor) binds to promoter region (TATA box) on template DNA strand

exons

expressed DNA sequences

introns

DNA sequences that code for nothing

post transcription processing

mRNA splicing, 5' cap, poly A tail

translation

mRNA --> protein

mRNA codons brought to ribosomes (large and small subunits), tRNA bring amino acids to ribosomes

substitution/point mutation

1 base is replaced

insertion/deletion mutations

add/delete a base

why mutations affect proteins

wrong base = different amino acids, different amino acids = nonpolar/polar, fold differently

DNA methylation

makes DNA pack more tightly around the histones, turning genes off