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week 2 by Mind Map: week 2

1. M

2. neo-darwinism the modern synthesis

2.1. evolutionary fitness

2.1.1. a measure of the ability of genetic material 2 perpetuate itself in the course of evolution

2.1.2. depends on individual's ability to survive rate of reproduction viability of offspring

2.2. Neo Darwinism

2.2.1. synthesis of Darwin's theory of NS and Mendelian theory of heredity

2.2.2. Darwin lacked a heredity theory Mendel's ideas discovered at turn of 20th cent. initially thought to count against Darwin Mendel's theory made it difficult to understand Darwin's theory

2.3. Mendelian Inheritance

2.3.1. Gregor Mendel (1822-1889)

2.3.2. >28,000

2.3.3. Mendelism generally accepted theory of heredity since 1920s basis of all Modern genetics

2.3.4. Basic laws of inheritance Segregation Independant assortment

2.3.5. Mendelians vs biometricians Mendelians studied lrg diff. in organisms thought that evolution happened like a new species evolving from macroevolution in its ancestor Biometricians studied small interindividual diffs. and explained evolutionary change by transition of whole pops.

2.4. History

2.4.1. Fisher,Haldane,and Wright (1892-1964) created a synthesis of Darwinism and Mendelism showed that NS could operate with Mendelian genetics written around 1930 Haldane (1892-1964) "Causes of evolution "1932 coined the word clone came up with idea of inclusive fitness Fisher (1890-1962) "The Genetical Theory of Natural Selection" 1930 very quantitative (Statistician) theory of pop. genetics experimental design Wright (1889-1988) long paper "Evolution in Mendelian populations)=1931 4 volume treatise classic works of theoretical pop. genetics

2.4.2. Theodosius Dobzhansky(1900-1970) major book 1937 Genetics and the origin of species inspired by early neo Darwinism new genetic research in field and laboratory classical investigations of evolution in pop. of fruit flies(Drosophila) in 1927 under Stalin state oriented Science

2.4.3. Ernst Mayor (1904-2005) born and educated in Germany ornithological society study of birds systematics ppl who classify organisms based on phenotypes species dont interbreed provided framework of how species evolve allopatric species "Systematics and origin of species "1942 moved to US in 1930 pop. geneticists defined the members of a species by ability to interbreed rather than by morphological similarity to a type form Modern synthesis based on systematics

2.4.4. William D Hamilton (1936-2000) found solutions to 2 of Darwin's problems evolution of altruism evolution of sexual reproduction 1964 Genetical evolution of social behaviour key concept=inclusive fitness extended maths aspect of Haldanes book explained reason for unequal sex ratios sex ratios change during life span sex ratios depend on other conditions explained how NS acts on social behaviour=kin selection Famous formula and rule formula Hamilton's rule

2.4.5. John Maynard Smith ( 1920-2004) applied game theory to evolutionary biology Game theory economical theory outcome of ppts choice of action depends critically on actions of other ppts e.g. interaction between individuals in species 2 fold cost of sex finding a mate only half individuals have babies

2.5. Future of Neo Darwinism

2.5.1. 1930s-1940s neo Darwinism gradually spread through all areas of biology and became widely accepted unified genetics,systematics, paleontology,and classic comparative morphology and embryology epigenetics same info appearing in our lifetime cultural transmission transmit cultural knowledge to offspring Niche construction evo devo development,genes comparative genomics comparing DNA sequences and genomes of diff. organisms systematics biology experiments in factory like manner known as Postmodern synthesis

3. major transitions in evolution

3.1. macroevolution

3.1.1. broad pattern of evolution above the species level

3.1.2. e.g. emergence of terrestrial vertebrates through

3.2. 5 significances of major transitions

3.2.1. smaller entities coming together> form lrger entities (eukaryotes)

3.2.2. small entities become differentiated as part of lrger entities e.g organelles

3.2.3. smaller entities are often unable to replicate without the lrger entity

3.2.4. smaller entities can disrupt development of larger entity cancer

3.2.5. New way of transmitting info arises DNA>protein

3.3. Early Earth

3.3.1. 1920 Haldane early earth atm=reducing environment organic compounds could have formed from simpler molecules E for organic synthesis lightning/intense UV radiation early oceans =solution of organic molecules life arose from the "primitive soup"

3.3.2. 1953 Stanley Miller and Harold Urey tested the Oparine Haldane hypothesis under lab conditions > variety of AAs apparatus warmed flask of water model atm contained condenser results materials circulated through the apparatus analysis of contents after one week

3.3.3. some evidence suggests that early atm was made up of mainly N and CO2 neither oxidizing nor reducing

3.3.4. experiments similar to Miller-Urey neutral atm organic molecules

3.3.5. small pockets of early atm near volcano openings reducing 1st organic compounds may have formed near volcanoes and deep sea vents deep sea vents (smokers)

3.3.6. 2008 Canadian study volcanic-atm hypothesis found that numerous AA formed under volcanoes eruption conditions

3.3.7. 2nd source of organic molecules meteorites e.g carbonaceous chondrocites

3.4. Evolution of Replicators

3.4.1. evolution by hereditary replication compartmentalization info replicated is not losr

3.4.2. ribosomal RNA sequences are all similar all life (universal>come from common ancestor) LUCA last universal common ancestor

3.4.3. First replicators can' be DNA as it requires enzymes to unzip it and carry out rxns can't do anything expect bind to itself 1st genetic material most likely RNA RNA catalysts RNA How they evolved RNA molecules with certain advantageous base sequences RNA molecule with sequence that is best suited to surrounding environment (harsh) and has greatest ability to replicate itself occasional replication errors>mutations molecular biology of today might have been preceded by a RNA world small RNA molecules that carried genetic info were able to replicate and store info in vesicles Cofactors some AAs acted as cofactors AAs could have been cofactors or combos accelerate the rxns even more AA polymers selection favours AA cofactors and RNA together RNA vs DNA RNA can interact directly with the environment RNA can be read/replicated directly

3.4.4. Transition from RNA>DNA RNA life is limited high mutation rate asexual life cannot form process RNA sequences that carried genetic info appear in protocells RNA provides template on which DNA nucleotides are assembled DNA favoured as hereditary material

3.5. First prokaryotes

3.5.1. oldest eukaryotic fossils show that eukaryotic organisms first appeared 2.1 billion yrs old

3.5.2. eukaryotes vs prokaryotes eukaryotes have membrane bound organelles and prokaryotes dont eukaryotes have a cytoskeleton prokaryotes dont cytoskeleton in eukaryotes is used to change shape of cell and engulf other cells

3.5.3. Evolution of Eukaryotes from Prokaryotes endosymbiont theory endosymbiont suggests that mitochondria and plastids (chloroplasts) were small prokaryotes that began living within lrger cells prokaryotic ancestors of Mt and chloroplasts initially gained entry into cell as undigested prey (internal parasites) symbiotic RL beneficial bcuz mt evolved b4 chloroplasts evidence 4 theory process evolution from ancestral prokaryotes

3.6. Evolution of sex

3.6.1. +ve allows diff. genetic info from diff. ppl/organisms 2 combine

3.7. Multicellularity

3.7.1. Metazoa

3.7.2. presence of more than one kind of cell

3.7.3. common ancestor of multicellular eukaryotes lived about 1.5 billion yrs ago comparison of DNA sequences

3.7.4. oldest known fossils of multicellular eukaryotes 1.2 billion yrs ago fossils came from Ediacaran deposits in Australia Ediacaran fossils of soft bodied aquatic animals date back to 670-550 million yrs ago

3.7.5. transition from unicellular>multicellular occurred several xs

3.7.6. green algae (volvocales) inspiration for what may have occurred shared traits expt. evolved simple division of labour amongst differentiated cells common environment have flagella but cant reproduce have cells specialized for reproduction volvox

3.8. Eusociality

3.8.1. transition from a solitary lifestyle >eusociality (strict division of labour)

3.8.2. characterised by reproductive division of labour overlapping generations older helps younger cooperative care of young

3.8.3. seen in ants,bees, wasps

3.8.4. =highest level of organization of animal society

3.8.5. how they evolved evolution occurred repeatedly in diff orders of animals especially hymenoptera

3.8.6. Hamilton's rule genes for altruism increase in frequency when R x B > C kin selection an organism that favours reproductive success of relatives even at the expense of the organism's own survival and reproduction features 2008 study theory states that

4. geological timescales

4.1. complexity of life didnt evolve linearly

4.2. geological time record

4.2.1. 550 million yrs most/main geological time divisions in Earth history fossils less common b4 this

4.2.2. time divisions made on basis of characteristic fossil faunas fauna animals of a particular geological period

4.2.3. transition between 2 eras=transition between diff. characteristic fossil faunas

4.3. study of fossils helped geologists establish a geological record of Earth's history

4.4. numbers =billions of yrs

4.5. 30.5 billion yrs ago

4.5.1. universe formation

4.6. 4.6 billion yrs ago

4.6.1. origin of solar system and earth

4.7. geological time units

4.7.1. Eon>Era>period>epoch

4.8. biological radiation

4.8.1. an evolving grp that spreads into diff. environments and exhibits diversity of structures

4.9. 4 unequal eons

4.9.1. Hadean molten rocks Hades chaotic conditions in early earth solar systems still forming millions of yrs of violent impacts Late Heavy Bombardment by meteorites most water in gaseous form b4 rocks earth still largely molten geological studies differ

4.9.2. Archean ancient rocks 3.8 billion yrs ago oldest dating rocks Earth's crust cooled rocks and continental plates started to form LHB left earth and moon surface cratered intensive geological mixing on earth removed crater evidence plate tectonics churned and reworked Earth's surface middle Archean 3.5 billion yrs ago fossils of microorganisms and stromatolites 3.5>2.1 bya late Archean 2.7 bya O2 evolution

4.9.3. Proterozoic early life 2.5 bya fossil record changes fossils and rocks less metamorphosed stromatolites and other prokaryotic microfossils still present 2.1 bya eukaryotes first appear as microfossils 700-800 mya 1st glaciation(ice age) world's one big continental mass (Pangea) broke into small continents Dickinsonia Late proterozoic Ediacaran period smaller continents scatter on equatorial belt 1st multicellular eukaryotes 1.2 bya Pre Cambrian all animals were soft bodied little evidence of predation first 3 eons

4.9.4. Phanerozoic visible life 542 mya complicated,multicellular organisms, made a sudden appearance cambrian explosion sudden increase in diversity of many animal Phyla many present day animal phyla appear suddenly in fossils formed early in Cambrian explosion 535-525 mya Cambrian explosion late Proterozoic post Cambrian 3 Eras PMC Paleozoic Mesozoic Cenozoic

4.9.5. He Ate Pink Pickles

5. Major geological drives of evolution

5.1. 4 major geological drivers of evolution

5.1.1. Plate tectonics 1.5bya 3 occasions when most landmass of Earth formed a supercontinent and broke apart later 1. 1.1 bya 2. 600 mya 3. 250 mya estimate repeat in 250 mya from now Theory of plate tectonics continents are part of great plates of Earth's crust that float on hot, underlying portion of the mantle movements in mantle rate at which plates moving now can know past locations of radiations of continents impt. geological processes occur at plate boundaries e.g. mountain and island formations plates can Consequences of continental drift major impact on life on Earth alter habitats in which organisms live climate change when a continent shifts its location promotes allopatric speciation helps explain puzzles about the geographic distribution of extinct organisms explains a lot about current distribution of organisms Continental drift Earth's youngest major mountain range=Himalayas continues to drift today process

5.1.2. Vulcanism local climate change thermal vents, hot springs global climate change emission of gases new geological barriers formed migration New islands Malay Archipelago Galapagos Hawaii

5.1.3. Climate change

5.1.4. Meteorites consequences lrg scale migrations speciation mass exctinctions adaptive radiations

6. Catastrophism vs Uniformitarianism

6.1. Cuvier (1769-1832)

6.1.1. Catastrophism the principle that events in the past occurred suddenly and were caused by mechanisms diff. from those operating in the present evidence fossils show extinct species extinction and evolution (changes) occurs due to major, sudden catastrophic events

6.2. Hutton and Lyell (geologists)

6.2.1. Uniformitarianism Mechanisms of change are constant over time Lyell proposed that the same geological processes operating today were operating in the past at the same rate

7. Recent Major extinction events

7.1. mass extinction

7.1.1. when disruptive global environmental changes caused the rate of extinction to increase dramatically lrg # of species became extinct throughout the earth

7.1.2. loss of species from many diff. grps

7.1.3. takes lrg # of species

7.1.4. occur abruptly over relatively short period of time

7.2. 5 major extinction events

7.2.1. ordovician-Silurian End of ordovician-Silurian 85% of marine species extinct 10mys

7.2.2. Late Devonian (Permian Carboniferous) lasted less than 3mys 83% of marine species Tetrapods and early amniotes early mammals tropical conditions around equatorial landmasses>climate change>Increase in temps decaying undergrowth>coal increase in anaerobic organisms gd habitat 4 terrestrial invertebrates

7.2.3. Permian-Triassic late permian extinction 96% of marine invertebrates species lost (trilobites) emptied marine habitats around the world 7 insect orders 21 terrestrial tetrapod families 63% 70% terrestrial vertebrates b4 lrg vertebrates evolved (terrestrial) enormous volcanic eruptions extreme volcanism slow mixture of ocean water decreases O2 conc.s ocean anoxia suffocated oxygen breathers major extinctions=new niches

7.2.4. Triassic-Jurassic end of Triassic-Jurassic 4 mya many land vertebrates 80% of all marine species Jurassic/Cretaceous mammal like reptiles replaced as dominant land vertebrates by reptiles (dinosaurs) lizards,modern amphibian +early birds appear conifer and fern dominated vegetation

7.2.5. KTK-Pg Cretaceous Paleogene 60-65.5 mya lasted 41 million years 75% of all species extinct 50% of general including many adaptive radiations fill newly vacant niches major trigger meteorite evidence 4 chicxulub impact crater 65 myo scar beneath sediments off the Yucatan coast of Mexico Bolide impact of Chicxulub climate and temp change Tsunamis Additional causes some grps already declining Deccan traps (India)

7.3. Ongoing anthropocene extinction

7.3.1. caused by mankind

7.3.2. hunting

7.3.3. habitat destruction,modification and fragmentation

7.3.4. examples passenger pigeon 1914 dodo bird 1662 glyptodon 12000 yrs ago diprotodon 40,000 yrs ago New zealand megafauna not in decline b4 human colonization

7.3.5. causes pollution and overexploitation spread of invasive species e.g. pathogens Climate change Sumatran rainforest destroyed

8. Summary

8.1. the history of the earth is divided into geological time periods

8.2. these are defined by characteristic fauna flora

8.3. Large changes in biodiversity (mass extinction) were triggered by continental movement and catastrophic events