history of ppl making discoveries in evolution.txt

• oldest to have ideas of evolution
• Said all substances change their forms over time
• believed humans did too, that they evolved from fish

• believed animals evolved from randomly associated body parts
• ie: chimaera which had head of lion, wings of eagle)

Platonic idealism (fixity of species): the essence of something (ie: species) does NOT change over time

• agreed with Plato about fixity of species in HUMANS
• believed that Some species could change over time, although the categorized species could not move to another category

• species classification based on ANCESTRY and morphology
• (ie: something appearing to be a dog is classified as such b/c its parents were both dogs)

• uses Ray's definition of species using morphological criteria (homologous structures- same anatomical origins although DIFF fxns, vs analogous structure=same fxn, different anatomical origin)
• Classified higher taxonomic ranks: K, P, C, O, F, G

• species may change over time
• BIOLOGICAL species concept: ACCEPTED fixity of species, believes species are a group of related individuals that can INTERBREED to produce offspring
• all species w/in a genus have a similar ancestry in a genius, all species w/in fame have similar ancestor in family

• Uniformitarianism idea: Neptunists (geological processes are OCEANIC) and Plutomist (geological processes are VOLCANIC) both at work, but required time in MILLIONS of years (gradualism).
• Saw no beginning or end in time

• Change through Aquired Characteristics (ie: giraffe example, necks stretch & pass down this lengthening over time through generations). Also saw species never going extinct, will ADAPT and pass onto offspring.
• Thought >1 ancestor (vs 1 for Darwin's view)
• Species should be classified based on MORPHOLOGY (rather than via ability to interbreed of biological species concept)
• Agreed w/spontaneous generation
• Disagreed w/Aristotle that species remain fixed, but he thought the process of change was very slow

• Ridiculed Lamarck by disagreeing w/ following:
• 1. species originated through spontaneous generation
• 2. species could avoid extinction
• 3. uniformitarianism
• Thought earth was younger and believed in divine creation (God) to make new species
• Thought SPecies DO NOT evolve over time (ie: looked at fossils to see how it was and then followed by divine creation something new appeared)

• Estimated sequence of fossils bearing geological strata and divided into 3 eras:
• 1. Paleozoic Era (Age of Fishes) ie: Silurian
• 2. Mesozoic Era (Age of Reptiles) ie: Triassic
• 3. Cenozoic Era (Age of Birds & Mammals) ie: tertiary & quaternary

• Paleozoic (542-251mil y) - age of fish
• Mesozoic (251-65mil y) - age of reptiles
• Cenozoic (65mil-present) - age of birds & mammals

• Uniformitarianism idea: Contemporary processes occurring gradually may have taken millions of years (maintain geol processes & living species in equal)
• Stabilizing SELECTION: species could migrate & envir pressure would influence changes in species to allow for survival!
• REJECTED Curvier's catastrophism & progressionism
• AGREE w/Curvier that if species did NOT migrate, would go EXTINCT

• 1. Abiogenesis: abiotic origin of life (life originates from non-living sources) BUT agreed w/Pasteur that present day conditions do NOT allow for spontaneous generation
• 2. All life on earth shares common ancestor: including animals, plants & single celled org.
• 3. Mechanisms of change due to NATURAL SELECTION
• 4. Gradualism
• 5. Sympatric speciation more common than allopatric speciation (evolving due to different area-finches in Galapagos)
• 6. Anagenesis (single ancestor evolve into single descendent) more common than cladogenesis (ancestors and descendents BOTH exist at same time)
• 7. Hybrid sterility closely related to Species, NOT due to natural selection

• 1. all species have variability of species
• 2. species can reproduce in greater #s than world can sustain, so NOT all offspring survive
• 3. Survival of ind. w/in species not random (if more adapted, will survive in greater #'s) - opposed to Lamarck idea, probe due to Darwin's upbringing in an aristocratic society
• 4. As better adapted survive, eventually they evolve to become a new species

Mendel's law in hybridization: Explanation for DISCRETE inheritance in Changing PHENOTYPES

Evolutionary Change gradual (gradualism) by Blending inheritance over long periods

• Evolution by natural selection (ind formulated from Darwin)
• DISAGREED w/Darwin on following:
• Divine creationish: thought everything BUT humans could evolve from natural origins
• thought Species identification was objective, vs. Darwin who thought it was arbitrary
• Origin of hybrid sterility is important factor of maintaining species, vs. Darwin who thought it was a random occurrence

Batesian Mimicry: ie w/butterflies of similar colors, some harmless and some used to warn predators of poison. Harmless butterflies adapted to appear as poisonous to predators

• Darwin's bulldog - debator
• Hypothesized BIRDS evolved from DINOSAURS
• Agreed w/Lamarck's theory on hybrid sterility, did not see Darwin's argument for this

• 1st to construct 3 KINGOM taxonomy (adding protista to Aristotle's 2 kingdom)
• 1. protista
• 2. plantae
• 3. animalia

• rediscovered Mendel's law for discrete inheritance
• coined term MUTATION for sudden GENETIC changes (ie: roses producing different colors) w/recessive and dominant traits
• Saltationism: OPPOSED Darwin & Lamarck, by saying these mutations could account for evolutionary change

• Showed failure of artificial selection to alter uniform morphology of clonal plants
• Coined term GENE, GENOTYPE, PHENOTYPE

• Supported Saltationism mech. of evolution
• coined GENETICS - process of studying genotypes & phenotypes

Co-discovered Hardy-Weinberg law that (absence of evolution change) population will have same pheno & geno freq & same allele freq

• GENE theory of chromosomal inheritance: saw traits were coded by structures on chromosome (looked @ flies & breed to generate white eye flies)
• Identified region on sex determining chromosome

mix of discrete inheritance (Mendelian) and continuous inheritance

Co-Discovered Hardy-Weinberg law (p2 + 2pq + q2=1, p=dominant, q=recessive)

• "Neutralist school"
• role of RANDOM factors in speciation (due to genetic drift, gene flow & non-random mating)
• ie - emigration: high-->low pop density (cause decrease in abundance of alleles)
• immigration: low --> high pop density

• "Selectionist school"
• Adaptive Factors during speciation
• developed ANOVA test for determining if stat diff exist b/w results

• Nobel Prize: X-Ray radiation causes DNA breaks - if in coding region would cause LETHAL mutation
• Muller-Dobzhansky incompatibility: as you add more & more genes, probability of compatibility will DECREASE

• "balanced school of thought"
• Sex selection & competition of genes important in speciation
• Saw heterogenetic (ie: XY in males) as more severe in ref. to hybrid sterility

• Distinction b/w PRE & POST zygotic isolating mechanisms b/w species
• PRE zygotic isolation barriers: Behavioral barriers, Location barriers, Gametic Barriers
• POST zygotic isolation (order of severe to less severe):
• hybrid inviability (zygote doesn't survive)
• Hybrid sterility (ie-mule)
• F2 hybrid breakdown (2nd generation inviable..ie - Egyptian cotton)
• Behavioral F1 inferiority (ie - wolves & coyotes, even if mate, hybrid offspring not socially accepted into packs of either type)

Anagenesis & Cladogenesis observed in FOSSIL records

• 1. Biological species concept SUPERIOR to all other species def.
• 2. Allopatric speciation (species change due to geo change) more common than para or sympathetic speciation
• 3. Cladogenesis more common than Anogenesis
• 4. Found PERIPATRIC speciation - involves GENETIC drift and NATURAL selection�. when sub-population isolated from ancestral pop - usually smaller in size, less diversity of alleles (emigration) results in change of species
• says Peripatric speciation more common than phyletic gradualism during origin of species

• High freq of polyploidy in natural plant population
• allopolyploidy: due to fusion b/w 2 pop. (ie - peanuts originated by allopolyploidy)

• Anaximander of Miletus
• Emedoeles of Acragas
• Plato
• Aristotle
• John Ray (species based on ancestry & morph)
• Carlos Linnaeus (morph ideas - hom struc)
• Georges Louis Leclerc (BSC)
• James Hutton (Uniformit)
• Jean-Baptist Lamarck
• Georges Cuvier (divine cr�ation)
• Adam Sedgwick (eras)
• Charles Lyell (uniformit & stab selection - changing enviro & migration to allow change in species)
• Charles Darwin
• Gregor Mendel (discrete inheritance)
• Francis Galton (gradualism)
• Alfred Russel Wallace (diff hybrid sterility thought than Darwin)
• Henry Walter Bates (batesian mimicry)
• Thomas Huxley (Darwin's bulldog, birds from dinosaurs)
• Ernst Haeckl (3kingdom tax)
• Hugo de Vries (mutation, saltationism accounts for evolutionary change)
• Wilhelm Johannsen (genes, genotype, phenotype)
• William Bateson (coined genetics)
• Wilhelm Weinberg
• Thomas Hunt Morgan (flies, gene theory of chrom inheritance)
• Herman Nilsson-Ehle (mix of discrete & continuous inheritance)
• GH Hardy
• Sewall Wright (neutralist)
• RA Fisher (selectionist)
• Herman Muller (x-ray & muller & Dobzhansky-more genes=less compatible)
• JB S Haldene (balanced school, heterogene severe in hybrid sterility)
• Theodosins Dobzhansky (pre&post zygotic barriers)
• George Gaylord Simpson (clado & ango in fossil records)
• Ernst Mayr (BSC, allopatric, clado, peripatric spec)
• George Stebbins (polyploidy)