AP Bio Unit 7 - packet vocab

Biography

the geographic distribution of species

During Darwin’s studies he proposed..

the idea of descent w modification, which is the modern def of evolution

Evolution

change in the genetic makeup of a population over time; descent of modification

To explain the pattern of descent w modification (evolution) he observed, he proposed the idea of..

natural selection

Natural selection is…

a process in which individuals that have certain traits tend to survive and reproduce at HIGHER rates than other individuals bc of those traits

Natural selection acts on phenotypic variations in populations.. and

some phenotypes increase or decrease an organims’s fitness ( ability to survive and reproduce )

the theory of natural selection is based on 2 reasons…

traits are heritable and more offspring are produced than can survive

adaptations

inherited characteristics of organisms that enhance their survival and reproduction

more offspring are produced than survive means..

competition will occur, traits that lead to survival accumulate in a population as populations evolve NOT INDIVIDUALS

natural and artificial selection leads to..

evolutionary change

population

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

gene pool

a populations genetic makeup that consists of all copies of every allele type

if there is only one allele present for a particular locus in a population then it is..

fixed

many fixed alleles =

less genetic diversity

micro evolution

small scale genetic changes in a population

evolution is driven by random occurrences like

mutations, genetic drift, gene flow, natural selection

mutations can result in genetic variation and can

form new alleles

genetic drift def

chance events that cause a change in allele frequency from one generation to the next

genetic drift!

• most significant to SMALL populations

• can lead to a loss of genetic variation

• can cause harmful alleles to become fixed

• does NOT produce adaptations

• two types : bottleneck and founder

bottleneck effect

large population is drastically reduced by a natural disaster

some alleles may become overrepresented, underrepresented, or absent

founder effect

few individuals become isolated from a large population and establish a new small population w a gene pool that differs from a large population ( lose genetic diversity)

gene flow

transfer of alleles into or out of a population due to fertile individuals or gametes

alleles can be transferred between populations

reproductive success is measured by

relative fitness

directional selection

selection towards ONE extreme phenotype

stablizing selection

selection towards the mean and against extreme phenotypes

disruptive selection

selection against MEAN ONLY, both extreme phenotypes have the highest relative fitness

sexual selection

species w showy traits (peacocks)

Hardy Weinberg

determines what the genetic makeup of the population would be if it were NOT evolving, then its compared to actual data

• if there are no differences, then the population is NOT evolving

Hardy Weinberg principle

frequencies of alleles and genotypes in a population will remain constant w mendelian segregation and recombination of alleles are active

five conditions of Hardy Weinberg equilibrium

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

if any of that happens the micro evolution occurs

p and q

allele frequencies

p² and q²

individual organisms

primary sources of evidence

fossil record, comparative morphology, biogeography

fossil record

gives a visual of evolutionary change over time ; examined by carbon 14 decay

comparative morphology

analysis of the structure of living and extinct organisms

homology

characteristics in related species that have similarities even if the functions differ

embryonic homology

many species have similar embryonic development

vestigial structures

structures that are conserved even though they are no longer have a use

molecular homology

many species share similar DNA and amino acid sequences

homologous structures

characteristics that are similar in 2 species bc they share a common ancestor

analogous structures

structures that are similar but have separate evolutionary origins (ex. wings in bats and bees)

convergent evolution

similar adaptations that have evolved in distantly related organisms due to similar environments

structural evidence indicates common ancestry of all eukaryotes

many fundamental and cellular features and processes are conserved across organisms

cellular examples: membrane bound organelles, linear chromosomes, INTRONS in genes

biogeography

the distribution of animals and plants geographically

systematics

classification of organisms and determining their evolutionary relationships

taxonomy

naming and classifying species

phylogenetics

hypothesis of evolutionary history

to determine evolutionary relationships, scientists use..

fossil records, DNA, proteins, homologous structures

phylogenytic trees

diagrams that represent the evolutionary history of a group of organisms similar to cladograms, BUT the trees show the amount of change over time measured by fossils

line of cladogram

reps a lineage

branching point on cladogram

is a node

nodes rep…

common ancestors

nodes and all branches

clades

species in a clade have..

shared derived features

root…

common ancestor of the species

unbranched

basal taxon

synapomorphy

a derived characteristic shared by clade members

derived characteristic

similarity inherited from the most recent common ancestor of an entire group

ancestral characteristic

similarity that arose prior to the common ancestor

monophyletic group

includes the most common ancestor of the group and all descendants (clade)

paraphyletic group

includes the most common ancestor of the group, BUT NOT ALL THE DESCENDANTS

polyphyletic group

does not include the most common ancestor of all members of the group

if there are conflicts use the principle of parsimony..

uses the hypothesis that requires the fewest assumptions (DNA changes)

species

a group able to interbreed and produce viable fertile offspring

speciation ( occurs due to reproductive isolation )

formation of new species; results in diversity of life forms

geography has an impact on what

…speciation

allopatric

physical barrier that divides population, or small population is separated from main population

populations are geographically isolated, and prevents gene flow

symbatric

a new species evolves while still inhabiting the same geographic region as ancestral species via the exploitation of a new niche

prezygotic barriers (habitat, temporal, behavioral, mechanical, gametic isolation)

prevents mating or hinders fertilization

habitat isolation

species live in diff areas or they occupy different habitats within the same area

temporal isolation

species breed at diff times of day, year, or season

behavioral isolation

unique behavioral patterns and rituals separate species

mechanical isolation

the reproduction anatomy of one species doesn’t fit w the anatomy of another species

gametic isolation

proteins on the surface of gametes don’t allow for the egg and sperm to fuse

postzygotic barriers (reduced hybrid viability, reduced hybrid fertility, hybrid breakdown)

prevent a hybrid zygote from developing into a viable fertile adult

reduced hybrid viability

the genes of different parent species may interact in ways that impair the hybrid’s development or survival

reduced hybrid fertility

a hybrid can develop into a healthy adult, but it is sterile - usually results due to differences in number of chromosomes between parents

hybrid breakdown

the hybrid of the first generation may be fertile, but when they mate w a parent species or one another, their offspring is sterile (f2 )

micro-evolution is the change of…

allele frequencies within a species or population (natural and sexual selection, genetic drift, gene flow)

macro evolution

large evolutionary patterns, extinctions, adaptive radiation

stasis

no change over long periods of time

Adaptive radiation is

if a new habitat or niche becomes available, species can diversify rapidly

punctuated equilibrium

when evolution occurs rapidly after a long period of stasis

gradualism

when evolution occurs slowly over thousands of years

convergent

two different species develop similar traits despite having def ancestors

divergent

groups w the same common ancestor evolve and accumulate differences resulting in the formation of a new species

early earth contained inorganic molecules, that couldve been synthesized….

organic molecules due to free energy and ABUNDANT OXYGEN.. or meteorites

Oparin and Haldane hypothesized that early earth was primarily composed of….

hydrogen

methane

ammonia

water

stanley miller and Harold urey tested the hypothesis in their lab and as a result they

found organic compounds and amino acids formed

stanley miller and Harold urey hypothesized that the organic molecules that formed served as the

buliding blocks for macromolecules

RNA world hypothesis

proposes that RNA could have been the earliest genetic material, and explains the pre-cellular stage of life