Evolution exam 1

coalesce

go back in time from present

synapomorphy

shared derived character

evolution

change in allele frequencies within a population over generations

mutation

a random error in gene replication that leads to a change

genotype

genetic makeup of an organism

phenotype

physical characteristics of an organism

genetic drift

random change in allele frequencies that occurs in small populations

absolute fitness

number of offspring an individual has

relative fitness

the contribution an individual makes to the gene pool of the next generation relative to the contributions of other individuals

adaptation

mutant phenotypes that increase fitness

natural selection

optimizes fitness in an environment

homology

phenotypic similarity in characteristics of two species due to inheritance from a common ancestor

phylogeny

evolutionary family tree

node

branching point on tree (where lineage splits)

clade

a group of species that includes an ancestral species and all its descendants.

vestigial

something in an underdeveloped form

relaxed selection

removal or weakening of selection that was important in maintaining one or more trait

mutation accumulation

accumulation of random detrimental mutations

antigen drift

gradual mutation of the virus/bacteria

antigen shift

sudden reassortment of different viral strains of the same type

Carolus Linnaeus

father of taxonomy

taxonomy

science of classification

Carl Woese

pioneer in molecular phylogenetics

Georges Cuvier

father of paleontology

James Hutton

believed that ancient processes like those that shaped the earth are the same as those active now

Charles Lyell

wrote principles of geology, uniformitarianism

William Smith

created geological map of Britain

principle of faunal succession

within any layer of rock, different types of fossils succeed one another in the same relative order

radiometric dating

dating using decay of radioactive isotopes.

radioisotopes

isotopes that have unstable nuclei and undergo radioactive decay.

half life

length of time required for half of the radioactive atoms in a sample to decay

hadean

"late heavy bombardment"

no permanent crust

life appears to have begun

end of asteroid bombardment

crust solidifies

oldest rocks date here

Archaean Eon

life widespread

anoxygenic photosynthesis & chemolithoautotrophy dominate

life is limited by available electrons from minerals

no O2 so minerals are reduced

Proterozoic

aerobic metabolism dominates

eukaryotes appear

life is limited by availability of key nutrients

size of biosphere increases exponentially

phanerozoic

"Visible life"

horizontal gene transfer

transfer of genes between cells of the same generation

trace fossils

provide evidence of the activities of ancient organisms

biomarkers

organic molecules that indicate the presence of life

molecular clocks

models that use mutation rates to measure evolutionary time

great oxygenation event

oxygen

cyanobacteria become widespread

atmosphere becomes similar to modern form

ocean rusts

cambrian explosion

sudden appearance of diverse macroscopic life

most modern phyla are present

immediately follows a snowball earth catastrophe

anagenesis

species formation without branching of the evolutionary line of descent.

K

T extinction

all non

avian dinosaurs disappeared

likely caused by 10

mile wide asteroid that impacted modern

late permian extinction

90% of all species, 99% of all marine species, rapid (60,000 years)

likely caused by siberian traps (large igneous province)

tips

terminal ends of evolutionary tree

branches

lineages evolving through time between divergence events

root

node connecting the focal species to some outgroup

systematics

scientific field dedicated to the classification of organsism

monophyletic clade

consists of the ancestor species and all its descendants

cladogram

only show branching patterns and ancestry

topology

branching structure of tree

phylogram

uses evolutionary distance to determine branch length

chronogram

uses time to determine branch length

sister taxa

clades that diverge from the same proximate ancestral node

homoplasy

shared characteristics without common ancestry

convergence evolution

the evolution of similar traits in unrelated lineages

polytomy

an unresolved pattern of divergence

algorithm

a step

distance matrix

clusters taxa based on genetic distance

character matrix

an array of taxa and characters that contains the character states for the taxa

outgroup

a group that one does not belong to or identify with

bootstrapping

create lots of trees by random method

count how often a given clade appears over many random trees

subfunctionalization

descendant of the duplicated gene has fewer functions than the ancestor

neofunctionalization

descendant of duplicated gene evolves a different function from the ancestor

spread, diffuse, invade

go forward in time to present

fixed

an allele becomes 100% of the population

(selective) sweep

allele in the process of becoming fixed

Motto Kimura

discovered most evolution at genetic level is neutral due to drift

synonymous substitutions

do not change protein

should evolve at a different rate due to drift

nonsynonymous substitutions

change protein

positive selection

faster evolution than synonymous sites indicates

purifying selection

slower evolution than synonymous sites indicates

Tom Ray

created Tierra

Chris Adami/Charles Ofria/ Titus Brown/Cliff Bohm

created Avida

3 components define fitness of replicators

longetivity

fecundity

accuracy

primordial nuclides

present since before earth formed

cosmogenic nuclide

created by interaction between stable isotope and cosmic ray