Evolutionsbiologie

Chemical state of early earth still debated; What reaction could have happened and wehether amino acids, sugars and carbs synthesized spontaneously; Building molecules from meteorites, Evidence: L-stereoisomer excess in some meteorite

Early earth had necessary ingredients and conditions => Pre-biotic soup

Miller mixed methane, ammonia hydrogenand electricity and found spontaneous formation of amino acids and others; BUT early atmosphere had different conditions, more CO₂ and N₂, and not as reductive as suspected; Oro found adenine spontaneously formed of ammonia and HCN

Building blocks is reversed by hydrolysis in H₂O; Clay can counteract hydrolysis and catalyze polymer formation; Polynucleotides up to 50 units long

Different approaches to construct tree of life, but none is perfect

Cross connections in deep past; LUCA may have been more of a community of gene-exchanging organisms than single defined species

Compression fossils: 2D impression from organic material buried in sediment before decomposition; Casts and molds: fully buried in sediment before decay, sediment hardens areound remains (mold) or gets infiltrated by compounds that later harden into rock (cast); Permineralized fossils: remains buried and minerlas precipitate in cells; Unaltered remains: depostied under rare conditions that prevent decomposition

Depends on: 1. Inherent durability of biological material 2. Burial conditions 3. Degree of anaerobicity; Hard body structures in depositional environments dominate records

Geographically: most fossils from lowlands/marine habitats; Taxonomically: Non-random geographic distribution and variation in cell/body composition; Temporally: Recycling of earth's crust results in loss of fossils; Very old fossils sufficient in number and diversity to help understand branching events

Almost all animal phyla first appeared in the fossil record during 40 my Cambrian period

Cambrian animals had wider variety of predator types; Proterozoic photosynthesis increased marine O₂ levels => larger bodies and faster metabolism made possible => Morphological explosion

Microevolution: Extensive evolutionary change in populations; Speciaition: Evidence for recent or incipient speciaition; Macroevolution: fossil record, biogeographical distributions, cross-species comparative analysis

Evolution associated with naturalism; concerns about relativism, no basis for morality, why care about common good, well being of neighbor, why not cheat; conerns about metaphysical despair; Not compatible with some creation narratives; Decrease in nobility and uniqueness of being human

Biological relationship to ancestral and extant primates; Geographical origins, morphological traits, tool use, social/sexual behavior, agriculture, language, mind & imagination, religion, art, morality, math % science

Longer skulls, bigger brow ridges, shortened canine teeth, fused wrist bones, less hair

bigger brains, loss of tail, more flexible hips, ankles, wrist and thumb; human vs. chimp DNA is less distant from each other than is either to gorilla DNA

Knuckle-walking, new dental and skeletal features, delayed sexual maturity, broad diet, range of habitats, tool use, culture

Chimpanzee: Male dominated societies, highly agressive males, primarily heterosexual; Bonobos: Female-dominated societies, strong female bondind, more homosexuality

Human synapomorphy => 23 vs- 24 chromosomes; Bigger brains, smaller teeth, fewer limbs for locomotion

African replacement: H. sapiens evolved in Africa and migrated to Europe and Asia and replaced local forms without hybridization; Hybridiziation and assimiliation: H. sapiens svolved in Africa and replaced local populations with extensive hybridization between newcomers and local residents; Multiregional evolution: H. sapiens evolved concurrentlyin Europe, Africa and Asia with sufficient gene flow among populations to maintain continuity as a species; Candelabra: Independent evolution without gene flow, BUT humans are very closely related to each other, compared to other primate species

1. Heritable traits vary across organisms 2. More organisms are born than reproduce 3. Reproduction to different degrees 4. Some variations enhance survival anr reproduction 5. Advantageous variations will spread over generations

Change in organisms and populations over time; Evidence for common ancestry; Evidence from biogeographical distributions; Evidence that our planet is really old

Direct observation: small time-scales => short-term changes => microevolution

Indirect observation : long time-scales => long-term changes => macroevolution

Development of beak lengts after introduction of tree with new fruit. How to test if it's genetic or environmental? Get samples of bugs and breed them in the lab and check on the beak lengths. BUT correlation does not imply causation!

It's a useless or rudimentary version of a body part that has an important function in other closely allied species; Ex: Kiwi's wings, remnant hind limbs of the rubber boa; These are descendants with modification from ancestors, which had fully developed body parts.

1. Coccyx: base of spine; starts as seperate bones then fuse into lump; coccyx development controlled by genes homologous to tail genes in closely related species 2. Arrector pili muscle: base of hair follicles; makes hair stand, goose bumps; we're descendants from hairier ancestors 3. Appendix: vestigial form of a cecum. BUT 70% of primates have appendix despite having a cecum; may be a safe house for good gut bacteria in cases of bad diarrhea.

In 1801 Geroges Cuvier claimed that 23 species were extinct. Some of the species were so big, that it was very unlikely that they still lived wothout being discovered. Darwin claimed that extinct species were relatives of living organisms => Evidence for change over time

General pattern of correspondence between fossil and living forms from same region => Todays species decended with modifications from ancestors of the same region

Transitional Species => Evidence of transformation in progress; Ex: Archaeopteryx is a bird with modern feathers but dinosaur-like skeleton; Not necessarily on direct line dinosaurs => birds, but more likely on an extinct side branch; Birds are closely related to Maniraptors, extinct theropods like T-Rex, Velociraptor, ...

Similarity due to to the inheritance of traits of a common ancestor; Genetically and phenotypically defined; enables the use of model organisms as representative for a whole group of organisms; Ex: Vertebrate forelimbs are similar despite their different functions and apeearances

Similiar function but different design => Convergent evolution; Ex: Sharks and whales with similar streamlined shape, short fins and tail, but developed independently

Evidence that one species can split in two; Ex: Greenish warbler: Birds interbreed everywhere except in one specific region where they don't => splititng in two species

Special Creation: James Ussher, The Bible, Earth is 6000 years old, created by God on the 23rd October 4004 BC; Theory of Uniformitarianism: Hutton & Lyell, rocks and fossils, Earth is unimaginably old, gradual change of Earth

Superposition: Young rocks are deposited on top of old rocks; Original Horizontality: Tipping/Bending occured after deposition; Cross-cutting relationships: rocks that intrude into seams of other rocks must be younger than the host rocks; Faunal succession: Old fossils simpler than young ones, younger are more similar to present forms

=> Chronology of relative dates = geologic time scales

At beginning earth was molten => no radiometric dating; but we can use moon rocks/meteorites for dating => 4.6 bio. years. Initial parent-daughter ration muest be known Ex: Potassium-argon dating, No argon-40 in the beginning because gaseous would bubble out of liquid rock, but accumulates in solid rock and doesn't migrate

Life has evolved for at least 2.7 bio. years

Human have selectively bred desirable traits in plants and animals for millenia; Crop plants, garden plants, domestic animals; Darwin studied pigeon breeding; Ex: Different forms descending all from wild cabbage, varieties of the same species

Because artificial selection is a thing, same process must happen at different speed in nature; so Darwin formalized the process Natural Selection what lead to the pattern Descent with Modification

Evolutionary Change is a deductive implication of four postulates:

1. Individuals within populations are variable 2. Variations among individuals are partially passed from parent to offspring 3. Some individuals are more succesful at surviving and reproducing than others 4.Survival and reproduction of individuals are not random, they are tied to variation among individuals, the most favourable variations are being selected

1. Variation among individuals => white & yellow flowers 2. Some variation is heritable => Dominant allele S for white, recessive allele s for yellow 3. Do individuals vary in success? Yes, differnet number of bee visits 4. Is Reproduction nonrandom? Bees prefer white plants, slightly more seedproduction

Testing the prediciton: Did the population evolve? Yes, there were more white flowers