Fundamentals of Evolution Final

Carolus Linnaeus

- purpose of natural science is to catalogue God's creations and reveal their pattern
- established the framework for modern hierarchical scientific classification using binomial nomenclature

Georges Louis Leclerc

- each species has an unchanging "internal mold"
- proposed that closely related species may have arisen from a common ancestor

James Hutton

- father of geology
- deduce that geological time was much longer than previously thought due to patterns of deposition and erosion seen in strata of cliffs

Georges Cuvier

- became the world's expert on the anatomy of animals
- proponent of catastrophism
- Established extinction as fact

Charles Lyell

- uniformitarianism: earth shaped by slow moving forces over very long
- contradicted catastrophism: earth shaped by biblical catastrophes

Jean-Baptisete Lamarck

- change through use and disuse
- inheritance of acquired characteristics in animals life time

Charles Darwin

- often credited with discovering evolution
- actually built upon others work
- should be credited with discovering the means by which evolution occurs

Voyage of the Beagle

5 year voyage where Darwin collected fossils, noted geology, and collected specimens which he sent to Cambridge

Alfred Wallace

conceived the theory of evolution through natural selection

Two major themes of Origin of Species

- decent with modification (all species descended from 1 or few common ancestors and accumulated differences over time)
- theory of natural selection

Darwin's Theory of Evolution

- organisms change over time (evolutions)
- species diverge from common ancestor (common decent)
- changes occur gradually over time
- changes occur in the proportions of individuals within a population
- Natural selection: changes the proportions of individuals are caused by differences in their ability to survive and reproduce

Microevolution

evolutionary change within a species or small group of organisms, especially over a short time period (one generation to the next)

Macroevolution

refers to evolution above the species level (broadest trends in evolution

Creationism

opposes the teaching of evolution in public schools

What are the 6 lines of evidence for evolution?

- biodiversity
- biogeography
- fossil records
- embryology
- comparative anatomy
- molecular evidence

Biodiversity

- many different ways to be an organism
- species are adapted to their environments by natural selection

Biogeography

- study of geographic distributions of organisms
- combines geology, paleontology, systematics, and ecology

Continental drift

the movement of continental plates through the action of currents generated deep within the molten rock mantle

Vicariance

evolutionary separation of species by barriers such as those formed by continental drift

Fossil record

- only direct evidence of macroevolutionary processes
- usually incomplete

Theory of Recapitulation

a largely discredited biological hypothesis that the development of the embryo of an animal goes through stages resembling stages in the evolution of the animals remote ancestors

von Baer Law

features common to a more inclusive taxon, often appear in ontogeny before the specific characters of lower-level taxa

Homologous structures

structures with different appearances and functions that are all derived from the same body parts in a common ancestor
- product of divergent evolution

Analogous structures

superficially similar structures that were independently derived
- product of convergent evolution

Speciation

the origin of two species from a common ancestral species
- bridges the evolution of populations and the evolution of taxonomic diversity

Reproductive isolation

biological differences between the populations reduce gene flow between them, even if they aren't graphically separated

Isolating mechanisms

gene flow between biological species is partially or entirely prevented by biological differences

Prezygotic barriers

- geographic isolation
- ecological isolation
- behavioral isolation

Gametic isolation

gametes of different species fail to unite

Hybrid inviability

hybrids have lower survival rates than non-hybrids

Allopatry

Species or distinct populations with geographic ranging that are separate from one another

Sympatry

species or distinct populations with overlapping geographic ranges

Parapatry

species or distinct populations with adjacent but nonoverlapping geographic ranges

Hybrid zone

a region where genetically distinct parapatric forms interbreed

Cline

a gradual change in a character or allele frequencies over geographic distance

Ecotype

a phenotype that is associated with a particular habitat

Taxonomy

the naming and classification of organisms

Systematics

classification of organisms based on evolutionary relationships

Phylogeny

a hypothesis about patterns of evolutionary relationships

Phylogenetics

the reconstruction and study of evolutionary relationships

Characters

traits of an organism

Outgroup

a more distantly related organism that serves to root a tree

Derived chatacter state

a character state shared by a group of OTU's that is not the ancestral state

Synapomorphy

shared derived character state

Homoplasy

independent evolution of similar traits that is a result of:
- convergent evolution
- evolutionary reversal; return to an earlier character state

Rapid diversification

three or more species arising during a short period of time

Introgression

movement of genes from one species or population into another by hybridization and backcrossing

Monophyletic group

represent a single evolutionary group containing the ancestor and all its decedents

Paraphyletic group

some, not all, of the descendants of an ancestor are present in the group

Polyphyletic group

doesn't include the most recent, common ancestor

Polymorphism

results in mimics by the species

Purines

adenine and guanine

Pyrimidines

thymine and cytosine

Exons

gene segments that code for protein

Intron

noncoding segments that occur between exons

Hyplotype

a particulare DNA sequence that differs by one or more mutations

Mutation

the process of alteration of a gene or chromosome and its products

Transition

a substitution of a purine for purine or pyrimidine for pyrimidine

Transversion

substitution of a purine for a pyrimidine or vice versa

Synonymous mutations

have no effect on the resulting amino acids, polypeptide or protein

Karyotype

a description of the complement of chromosomes

Aneuploidy

unbalanced chromosome complement

Polyploidy

changes in whole sets of chromosomes

Phenotypic platicity

the capacity of an organism of a given genotype to express different phenotypes under different environmental conditions

Norms of reaction

the variety of different phenotypic states that can be produced by a single genotype under different environmental condition

genotype frequency

the proportion of a population that has a certain genotype

Hardy-Weinberg equilibrium

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

Linkage

physical association of genes on the same chromosome

Quantatitative traits

a measurable phenotype that depends on the cumulative actions of many genes and the environment

Isolation by distance

the further apart 2 or more populations are from one another, the more genetically dissimilar they are

Ring species

two populations which do not interbreed are living in the same region and connected by a geographic ring of populations that can interbreed

Genetic drift

random fluctuations in allele or haplotype frequencies

Bottleneck

a severe or temporary reduction in population size

Founder effect

genetic drift in a small colonizing population

Inbreeding depression

the resulting decline in fitness and fecundity that occurs when closely related individuals reproduce

Natural selection

the process where organisms better adapted tp their environment tend to survive and produce more offspring

Teleology

the explanation of phenomena by the purpose they serve rather than by postulated causes

Adaptation

a characteristic that enhances the survival or reproduction of organisms that bear it relative to alternative character state

Fitness

reproductive success as measured by the average per capita rate of increase

Aposematism

a warning signal to potential predators that prey are toxic or noxious

Batesian mimicry

the resemblance in appearance of a palatable or harmless species to an unpalatable or dangerous species that is usually avoided by predators

Mullerian mimicry

the resemblance of an unpalatable or dangerous species to another unpalatable or dangerous species

Competitive exclusion prinicple

two competed species that use exactly the same resources cant coexist indefinitely

Resource partitioning

species divide limited resources to reduce competition

Character displacement

the phenomenon where differences among similar species whose distributions overlap geographically are accentuate in regions where the species co-occur, but are minimized or lost where the species distributions do not overlap

Group selection

a mechanism in which natural selection may favor an increase in fitness of a group of organisms, despite a reduction in individual fitness

Kin selection

natural selection in favor of behavior by individuals that increase the chance of survival of their kin

Preadaptation

a feature that originally evolved for a particular function that later serves a new and different function

Naturalistic fallacy

what is natural is necessarily "good"

Absolute fitness

the per capita growth rate of each genotype

Relative fitness

fitness of a genotype relative to that of a reference genotype

Purifying selection

selection that lowers the frequency of a selectively disadvantageous allele

Heterozygote advantage (overdominance)

when heterozygote has higher fitness than either homozygote

Heterozygote disadvantage (underdominance)

occurs when the heterozygote has a lower fitness than either homozygote

Antagonistic selection

opposing selective forces

Frequency-dependent selection

selection in which the fitness of a phenotype depends on its frequency relative to other phenotype in a given population

Inverse frequency-dependent selection

the rarer a phenotype, the greater its fitness

Positive frequency-dependent selection

the fitness of a genotype is greater the more frequent it is in a population

Anisogamy

dimorphism in gamete size

Parthenogenesis

reproduction from an egg without fertilization

Selective interference

reduction in the spread of an advantageous allele that results from selection acting on other loci

Mullers rachet

genomes of asexual populations accumulate deleterious mutations in an irreversible manner

Sexual selection

differential reproduction as a result of variation in the ability to obtain mates

Intrasexual selection

male-male competition

Alternative mating strategies

a strategy used by male/female animals, often with distinct phenotypes, that differ from the prevailing mating strategy of their sex

Intersexual selection

female choice

Lek

communal area in which 2 or more male of a species perform courtship displays

Good genes model

preferred male traits indicate higher viability, which is inherited by the offspring of the females who choose good males

Runaway sexual selection ("sexy son")

sons of females that choose a certain male trait have improved mating success because they inherit the trait that made their father appealing to their mothers

Altruism

an activity the enhances the fitness of other individuals but lowers the fitness of the actor

Reciptocation

a behavior where by an organism acts in a manner that temporarily reduced it fitness while increasing another organisms fitness, with the expectation that the other organisms will act in a similar manner at a later time

Hamilton's rule

an altruistic trait can increase in frequency if the benefit received by the relative, weighed by their relationship, exceeds the cost of the trait (rb>c)

Eusocialisty

the highest level of organization of animal sociality; is defined by: cooperative breeding care, overlapping generations withing a colony, and a division of labor into reproductive and non-reproductive groups

Coevolution

when two or more species reciprocally affect each others' evolution through the process of natural selection

Oparin-Haldane hypothesis

life arose gradually from inorganic molecules, with "building blocks", like amino acids forming first then combining to make complex polymers

Miller-Urey Experiment

provided the first evidence that organic molecules needed for life could be formed from inorganic components

RNA World hypothesis

the first like was self replicating RNA

Strata

distinctive fossil taxa in sedimentary layers known

radioactive dating

measure decay of certain radioactive elements

Precambrian life

only had prokaryotes for about 2 billion years, then archaea and bacteria came into play

Endosymbiosis theory

some of the organelles found in eukaryotic cells were once free-living prokaryotic microbes

Cambrian explosion

relatively short evolutionary event, beginning around 543 mya in the Cambrian period during which most major animal phyla appeared, as indicated by the fossil record

Paleozoic life

modern animal phyla first appeared, early chordates diversified dramatically, predator diversity increased dramatically, early ancestors of mammals first appeared

Colonization of land

terrestrial plants evolved from green algae, terrestrial biomass increased greatly

Vertebrate evolution

first terrestrial arthropods appeared in the Silurian, first terrestrial vertebrates evolved in the middle of Devonian

Sarcopterygii

group that gave rise to superclass tetrapod

Mesozoic Life

"age of reptiles", Pangea began to split, reptiles, birds and mammals became diverse

Diapsids

vertebrates with 2 temporal fenestrae, became the one of the most diverse groups of vertebrates

Synapsids

vertebrates with single temporal fenestra, diversity increased and gave rise to therapsids (mammal like reptiles) that gave rise to modern mammals

Cenozoic Era

North America split form Europe, marine animal /mammal diversity increased, mostly extant species evolved in Pleistocene, global temps fluctuated greatly

Refugia

areas with isolated populations that were formerly broadly distributed

Punctuated equilibrium

long periods of little change followed by short periods of rapid change

Habitat tracking

the shifting of the geographic distributions of species in concert with the distributions of their typical habitat

Three hypotheses to account for stasis:

- internal genetic/developmental constraints
- stabilizing selection for a constant optimum phenotype
- brief local divergence that didn't leave evidence

Saltation

sudden evolutionary changes that happen in a single generation, rather than gradually

Living fossils

organisms that have changed so little over millions of years that they closely resemble

Phylogenetic niche conservatism

tendency of species to retain their ancestral traits and maintain a long-continued dependence on much the same resources and environmental conditions

Mass extinction

when a large percentage of species go extinct in a short period of time

Five Mass Extinction Events

End Ordovician, late devonian, end permian, end triassic, cretaceous-tertiary (KT)

End ordovician

proportionally may have been the second largest extinction, 49% of genera went extinct

Late Devonian

may have been multiple extinction pulses,75% of all species went extinct

End Permian

most severe, 96% of all species of marine vertebrates, 70% of terrestrial plants

End Triassic

one of the least intense, 20% of marine families

Cretaceous-Tertiary

50% of all species extinct, evidence for large meteor impact

Passive trend

lineages in the clade evolve in both directions with equal probability

Active (driven) trend

changes in one direction are more likely than changes in the other

Predictability

the evolutionary history of life was inevitable, evolutionary parallelism/convergence are widespread and dictate evolutionary process

Contingency

the path of evolution has been directed by change events, such that that the outcomes of history would be different in any antecedent events had been different

Greater apes

- chimps and bonobos
- gorillas
- orangutans
- humans

Very early hominins

- sahelanthropus
- orroin tugensis
- ardipithecus

Early Hominins

- australopithecus
- paranthropus
- homohabilis
- homo erectus
- homo floreseinsis
- neaderthals
- homo sapiens

Multiregional hypothesis

independent multiple origins or shared multiregional evolution with continuous gene flow between continental populations occurs