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Life on Earth (Fossil Records (fossil record bias (favors hard shells,…

- - - - change took a long time to occur
        
        occurred in steps
      - anatomical features that fossilize readily
        
        ear bones
        
        lower jaw is one bone
        
        different parts of teeth
  - - - Archaean
      - Proterozoic
      - Hadean
      - Latest - Phanerzoic (0.5 bil yrs)
        
        encompasses most of time of animal existence
        
        .
        
        3 eras
        
        Paleozoic
        
        Mezosoic
        
        Cenozoic
    - - fisrts eukaryotic cells
        
        originated by endosymbiosis
        
        engulf cell that evolve into organelles
        
        serial endosymbiosis
        
        mitochondria that evolves before plastids
        
        Multicellularity
        
        older fossils are small eukaryotes
        
        earliest taxanomically recorded are red algae
        
        before edicaran period, everything was microbial
        
        Photosynthesis an O2
        
        first O2 produced dissolved in water
        
        oxidized iron
        
        precipitated then formed sediments
        
        doomed out many prokaryotes
        
        O2 gassed out and entered atmosphere
        
        Cambrian explosion
        
        most present day phyla suddenly appeared in fossils
        
        all animal were soft- bodied before this
        
        fist single-celled organisms
        
        fossilized stromatolites
        
        layered rocks that form when prokaryotes bind thin films of sediment
        
        3.5 bil yrs ago
        
        Colonization of land
        
        roots took time to become an adaptation for plants
        
        arthropods were the 1st animals to colonize land
        
        plants colonized land with fungi as well
  - - - decay of radioactive isotopes
        
        old fossils with little C-14 can't be dated
      - this process a radioactive "parent" isotope decays to a "daughter" isotope
        
        half-life, tie required for 50% of the parent isotope to decay
        
        not affected by temperature, pressure, or environmental variables
  - - - only fraction of the fossils were discovered
      - many fossils destroyed my geologic processes
- - - - paedomorphosis
- - - - discipline is focused on classifying organisms and determining their evolutionary reltionships
      - reconstruct phylogenies through systematics
    - - Evolutionary history of group of organisms displayed by phylogentic tree
        
        represents hypothesis about evolutionary relationships
        
        represents common ancestor of lineages that diverge
        
        relationsip depicted as branch points
        
        each tree has a branch point that shows common ancestors
        
        chimps and humans are considered a sister taxa
        
        groups of organisms that share a common ancestor that nobody else shares
        
        alltrees are rooted
        
        a branch point within the tree represents most common ancestor of all taxa in the tree
        
        lineage that diverges early is called basal taxon
    - - should not assume that taxon evolved from taxon next to it
      - can't infer ages of texa or branch points
    - - organisms tat share similar morphologies are likely to be more related than organisms with diff structures
      - phenotypic and genetic similarities due to shared ancestry homologies
    - - Cladistics
        
        approach to systematics where the common ancestor is primary criterion to classify organisms
        
        placing species into clades
        
        taxonomic categories of Linnaean syst that are nested with larges clades
      - taxon is equivalent to clade if it's monophyletic
        
        consists of ancestral species and all descendants
        
        Paraphyletic group
        
        consists of ancestral species and some, not all, of its descendants
        
        Polyphyletic group
        
        includes distantly related species but not most recent common ancestor
      - Shared ancestral character
        
        backbone because it predates branching of mammals, therefore it's shared for mammals
        
        character that originated in ancestor of taxon
      - Branch length
        
        proportional to amount of evolutionary change or times where particular events occurred
        
        maximum parsimony
        
        simplest explanation that's consistent with facts
        
        OKHAMS razor
        
        maximum likelihood
        
        identifies the tree that most likely produced a given set of DNA based on certain rules
    - - source of confusion is covergent evolution
      - complexity of whats being compared is a clue
        
        more parts that are similar, more likely that it evolved from that common ancestor
        
        same with comparisons at gene level
  - - - Binomial nomendature
        
        second is species
        
        brought in by Caolus Linnaeus
        
        introduced to eliminate language barrier
      - using scientific taxonomy
      - Hierarchical Classification
        
        DKPCOFGS, king phyllip came over for some good soup
        
        named taxonomic unit at any hierarchy called taxon
  - - - duplication increases number of genes in genome and more opportunities for evolutionary change
        
        types of homologous genes
        
        orthologuos
        
        homology is results of speciation event and occurs between genes found in different species
        
        paralogous
        
        homology results from gene duplication
        
        copies of these genes diverged within a species
    - - lineages that diverged long ago share many orthologous genes
      - number of genes a species has doesn't seem to increase through duplication at the same rate of perceived phenotypic complexity
  - - - neutral mutations
        
        harmful mutations are removed quickly
        
        neutral mutation rate is like clockwork
        
        explained by how important gene is
    - - certain changes are favored
      - molecular clocks only been used to date evolution divergences a longtime ago, assuming that clocks were constant at the time
  - - - eukaryotes can get nuclear genes from bacteria and archea
- - - - The abiotic (non living) synthesis of small organic molecules, such as amino acids and nitrogenous bases
      - The joining of these small molecules into macromolecules, such as proteins and nucleic acids
      - The packaging into protocells, droplets with membranes that maintained an internal chemistry different from that of their surroundings
        
        First genetic material is RNA not DNA
        
        Plays role in protein synthesis
        
        can make copies of short pieces of RNA
      - The origin of self-replicating molecules that eventually made inheritance possible
  - - - Earth cooled and H2O condensed to make oceans
      - H2 escaped to space
      - Volcanic vapors released into atmosphere
        
        nitrogen and its oxides
        
        carbon oxides
        
        methane, ammonia, and hydrogen
      - Early atmosphere made up of nitrogen and CO2 w/ no redox
      - first atmosphere
        
        thick with water vapor
        
        little oxgen
      - small pockets of early atmosphere near volcano has redox
      - Initially bombarded by leftover ice and rock
    - - tried to create conditions like early Earth
      - Produced amino acids and organic compounds
      - similar experiment used a neutral atmosphere
        
        Organic compounds produced in hydrothermal vents
        
        areas on seafloor where heated water and minerals flow in ocean
        
        Alkaline events
        
        high pH (9-11)
        
        warm water instead of hot
        
        abiotic synthesis of organisms possible in different conditions
        
        murchison meteorite
        
        4.5 bil yr old rock landed in Australia
        
        contained 80 amino acids not from Earth
    - - self-replicating molecules & metabolic source appeared
        
        abiotically produced vesicles
        
        conditions might have been in vesicles
  - - - called ribosomes
      - make complimentary copies of short pieces of RNA
- - - - this assumes that only complicated eyes are useful
- - - - Pangea formed
      - destroyed and formed habitats
        
        promotes allopatric speciation
        
        explains why fossils of the same species are in different continents
- - - - cretaceous
        
        extinguished more than 1/2 of all marine species
        
        iridium from meteorite made a cloud that blocked the sun
        
        eliminated many terrestrial creatures including all dinosaurs
      - Late Denovian
        
        cause: asteroid, massive flood of lava/drop in O2
        
        life in shallow seas were the most affected
      - ordavian
        
        caused by the drop in CO2
        
        3rd largest, affected life at sea
      - Permian
        
        defines boundary between Paleozoic and Mesazoic eras
        
        claimed about 96% of marine animals species
        
        terrestrial life was affected too
    - - Cause: humans
        
        messing up everything
    - - once evolutionary change is gone, it can never come back
      - takes 5-10 mil yrs for diversity of life to recover
      - Alter ecological communities by changing native population
      - adaptive radiations
        
        periods of evolutionary changes
        
        large scale radiations occurred after extinction
        
        world wide
        
        history of life greatly altered by radiations
        
        organisms that raise can serve as a new source of food
        
        adaptive radiations
        
        Hawaii
        
        few organisms go to new location w/ little competition