BIO 365- Evolution Final UMaine

Essentialism

each species has an "essence" of which each species is an imperfect form

Teleological

organisms are designed (have a purpose)

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