unit 9

evolution

descent with modification; process where species accumalate differentces from their ancestors as they adapt to different enviroments over time

fossils

remains or traces of organisms from the past

strata

super imposed layers of rock

paleontology

study of fossile

Aristole

viewed species as fixed (unchangin)

Carlous Linnaus

classify lifes diversity; binomial naming (homo sapein)

nested

grouping similars into categories

cuvier

old fossils are more dissamler to current fossils; through layers some new species appeared while others dissaperared.

catastrophism

major events cause extinsion

james hutton

earths geolgic features could be explained by gradual changes that r still in affect today (valley from river)

uniformitarianism

Charles lyell; mechanisms of change are similar/constant over time

jean- bapriste lamarack

evolutionary change in organism over time explain fossil pattern and why organism match their enviroment. mechanism: accuried charactersitcs (change phsycial traits), organism hv a drive to be more complex

adaptaions

inherited charactersitics of organisms that enhace their survival and reproduction in specific enviroments

descent with modification

concept that living organisms are related through a common ancestor and that species change (evolve) over time due to inherited variations and natural selection

natural selection

process where individuals that have certain inherited traits tend to survive and reproduce at higher rates than do other individuals because of those traits

artifical selection

selective breeding by humans for desired traits

homologous structures

similar body parts in different species that share a common ancestor

homology

similarities resulting from common ancestry

vestigial structures

remanants of features that served a function in the organisms ancestors (snake and whale)

evolutionary tree

diagram that reflects evolutionary relationships among groups of organisms; often represtn the pattern of descent from common ancestors

convergent evolution

independent evolution of similar features in differnet lineages (bird and butterfly)

analogus

body parts that have similar functions but evolved independently in different species

transitional fossils

fossilized remains of life forms that exhibit characteristics of both ancestral and descendant species, providing evidence of evolutionary change

pseudogenes

non-functional copies of functional genes that have accumulated mutations, rendering them incapable of producing a functional protein

biogeogrpahy

scientific study of geogrpahic distrubtution of species

microevolution

evolution on its smallest scale

genetic variation

differences among individuals in the composition of their genes or other DNA sequence

genetic flow

the movement of genetic material from one population to another

genetic drift

a random change in the frequency of alleles (gene variations) within a population over time, driven by chance events rather than natural selection

neutral variation

genetic differences between individuals within a population that do not confer a selective advantage or disadvantage, meaning they are not influenced by natural selection

cline

gradual change in population

population

is group of indiviudals of the same species in the same aread that interbreed and produce fertile offspring

gene pool

collection of all the genes within a population of interbreeding organisms, encompassing all the different alleles (variants) of those genes

sexual reproduction

process that involves two parents combining genetic information to create offspring

Hardy Weinberg Equilibrium

describes what happens when a population is NOT evolving

p²

frequency of homozygous dominant

2pq

frequency of heterozygotes

q²

frequency of homozygous recessive

hardy weinberg conditions

no mutaions (allels), random mating, large population, no gene flow, no natural selection

differential selection

process where certain individuals within a population are more likely to survive and reproduce than others, due to differences in their traits

adapative evoulation

where traits enhance survival or reproduction tend to increase in frequency over time

founder effect

smaller group may establish a new population whose gene pool differs from the source population

bottleneck effect

severe drop in population size; lose genetic variability and loss of viability (naturla disasdter)

relative fitness

contriubution an individual makes to the gene pool of the next gen telative to the contribution of other indivuiduals

directional selection

favor one extreme (common when enviromental change or migration)

disruptive slection

favor both extrems

stabalizing selection

favor intermediate

sexual dimorphism

differnece in secondary sex charactersitcis between the 2 sexes

intrasexual

indiviudlas of one sex compete for mate

intersexual

mate choice based off apperance or behavior

frequency dependent selction

an evolutionary process where the fitness of a phenotype or genotype is linked to its frequency within a population

heterozygote advanage

occurs when individuals carrying two different alleles (heterozygotes) for a gene have a greater fitness or reproductive success compared to those with two identical alleles (homozygotes)

speciation

evolutionary process by which new species form

microevolution

process of small-scale evolution that occurs within a population over a short period of time; change in allele frequencies

macroevolution

broad pattern of evolution above the species level

biolgoical species concept

defines a species as a group of interbreeding populations in nature that produce viable and fertile offspring

hybrids

offspring that result from an interspecifci mating

prezygotic barrier

block fertilization from occuring

post zygotic barriers

contribute to reporductive isolation after the hybrid zygote is formed

reporductive isolation

where different species cannot successfully interbreed, even if they share a habitat

morpholgical species concept

defines species based on their physical form and structure

elogical species concept

species as a group of organisms that share a specific ecological niche in their environment, meaning they are adapted to and use the same resources

allopatric speciation

when a species splits into two or more new species due to geographic isolation

sympatric speciation

process where new species evolve within the same geographical area without geographical isolation

polyploidy

genetic condition where an organism has more than two complete sets of chromosomes

autopolyploid

condition in which an organism has multiple sets of chromosomes, all derived from the same species

allopolyploid

an organism with multiple sets of chromosomes, where at least one set is derived from a different species than the others

hybrid zone

an area where two different species interbreed, creating hybrid offspring

reinfrocemnt

natural selection strengthens reproductive barriers between two species in a hybrid zone,

stability

continued formation of hybrid individuals

puncuated equalbrium

hypothesis that evolutionary development is marked by isolated episodes of rapid speciation between long periods of little or no change.

protocells

simplified, self-assembled structures believed to be precursors to early cells on Earth; droplets with membranes that maintained an internal chemistry differnet from that of their surroudnigns

radiometirc dating

calculates an age in years for geologic materials by measuring the presence of a short-life radioactive element

half life

tiem required for 50% of parent isotope ti decay

endosymbiosis

theory that eukaryotic cells evolved from prokaryotic cells through a symbiotic relationship where one cell was engulfed by another and then lived inside, eventually becoming an organelle

adaptive radiations

a rapid evolutionary diversification where a single ancestral species gives rise to a wide array of new species with diverse adaptations

heterochrony

describe changes in the timing of developmen

paedomorphosis

the retention of juvenile traits by an organism in its adult form

hometoic genes

master regulatory genes that determine the identity of body segments during embryonic development in animals and plants

phyologeny

study of how organisms are related through evolution. It's based on the idea that all species are descended from common ancestors.

systematics

he scientific study of the diversity of organisms and their evolutionary relationship; classfiying orgnisms and deternming their evoultionary relantionship

genus

a taxonomic rank used to classify organisms, placing groups of closely related species together

classfication system

family into roders into classes into phyla into kingdoms into domains

taxon

group of any rank, such as a species, family, or class

phylogentic tree

diagram that shows how different species or groups of organisms are related through evolution

branch point

represents the common ancestor of the two evolutionary lineages diverging from it

evolutionary lineage

continuous line of descent, tracing the history of a group of organisms, populations, cells, or genes from an ancestor to its descendants

sister taxa

two distinct taxa that share the same most recent common ancestor on a phylogenetic tree

basal taxon

a lineage that diverges early in the evolutionary history of a group and remains unbranched- outgorup

monophyletic

group of organisms that includes a common ancestor and ALL of its descendants

paraphyletic

a group of organisms that includes a common ancestor and some, but not all, of its descendants

polyphyletic

a collection of species that do not share a common ancestor

shared ancestral character

a trait that originated in a common ancestor of a group of organisms and is inherited by all members of that group

shared dervived character

traits that evolved in a common ancestor and are then passed down to its descendants, distinguishing a group of organisms from others

maxium parsimony

finding the phylogenetic tree that requires the fewest evolutionary changes (or character-state changes) to explain the observed data

maxium likelhood

identifies the tree that most likely to have produced a given set of DNA data based on certain probability rules about how DNA sequences change over time

orthologous genes

genes in different species that evolved from a common ancestor through speciation

paralogous genes

gene duplicates within the same species, arising from a single ancestral gene after a duplication event

molecular clock

tool that estimates how long ago species diverged by measuring genetic mutations in their DNA or proteins

loci

refers to the specific physical location of a gene on a chromosome