Please enable JavaScript.

Coggle requires JavaScript to display documents.

Ch.22 &23 - Coggle Diagram

- - - - Scala naturae: fixed ladder of life; (Ex: Aristotle’s ladder with humans at top)
        
        Fixed species:species unchanging(ex:Old Testament view → each species designed for a purpose
        
        Old Testament creation:species individually created; perfect and unchanging(ex:Ex: organism adaptations seen as evidence of divine design
        
        Linnaeus → binomial nomenclature: two‑part naming system for species(ex: Homo sapiens (genus + species)
        
        Nested classification: grouping species into increasingly inclusive categories(ex:species → genus → family → order → class → phylum → kingdom)
    - - Cuvier → catastrophism: sudden events causing extinctions; (ex:flood wipes out species )
        )
      - Strata, extinction:sedimentary rock layers showing older → younger fossils; disappearance of species(ex:deeper strata = more dissimilar fossils)
      - Hutton → gradualism:slow, continuous geological processes shape Earth (ex:valleys formed by rivers over long periods)
      - Lyell → uniformitarianism:same geological processes acting now also acted in past, at same rate (ex:erosion today = erosion millions of years ago)
    - - Use & disuse:body parts used → stronger; unused → shrink(ex:giraffe stretching neck → neck becomes longer)
        
        Inheritance of acquired traits:traits gained during life passed to offspring
        
        Innate drive to complexity:organisms naturally progress toward greater complexity(ex:simple ancestors → more complex forms over generations)
  - - - Mockingbirds:similar birds on different Galápagos islands; slight variations
      - Finches → beak variation:beak shapes adapted to specific island food sources(ex: cactus‑eater with long sharp beak)
      - Island endemism:species found only on specific islands; not found anywhere else(EX: Galápagos species resembling mainland species but unique to the islands)
      - Colonization + diversification*Ancestral species arrives → spreads → evolves into multiple new species
    - - Lyell’s geology:Earth shaped by slow, continuous processes
        
        Malthus (population limits)populations grow faster than resources; struggle for existence
        
        Artificial selection examples:humans choosing traits to breed; rapid change in species
  - - - Adaptation:inherited trait improving survival/reproduction(ex:cactus finch’s long, sharp beak for cactus flowers)
        
        Fitness:ability to survive + produce offspring(ex:MRSA strains reproducing rapidly under antibiotic pressure)
        
        Natural selection = editing, not creating:selects among existing variation; does not generate new traits(ex:methicillin selects resistant S. aureus already present
        
        Depends on environment:(ex:soapberry bug beak length changes with fruit depth in different regions)
  - - - similarity due to shared ancestry(ex:mammalian forelimbs built from same bone pattern
        
        Anatomical →forelimbs: same structural layout, different functions(ex:human arm, cat leg, whale flipper, bat wing (same bones))
        
        Embryological → pharyngeal arches, tails: shared developmental features in embryos(ex:ertebrate embryos with post‑anal tail )
        
        Molecular → DNA, genes:shared genetic sequences inherited from common ancestor
        
        Vestigial structures: emnants of ancestral features with little/no function(ex: snake pelvis; blind cave fish eye remnants)
    - - Transitional forms:fossils showing intermediate stages between groups
        
        Cetacean evolution: land mammals → fully aquatic whales(ex:
        
        Stickleback pelvis reduction:consistent fossil trend of shrinking pelvic bones (ex: fossil sticklebacks showing reduced pelvis over thousands of years
    - - Continental drift: slow movement of continents altering species distribution
        
        Island species:unique species evolving in isolation
- - - - Historical constraints
        
        Def: evolution builds on existing structures
        
        Ex: mammal forelimbs modified from ancestral limb pattern
      - 2. Compromises
        
        Def: traits serve multiple functions; trade‑offs
        
        Ex: human pelvis → balance between childbirth + upright walking
      - 3. Chance events
        
        Def: random changes affecting populations
        
        Ex: genetic drift altering allele frequencies
      - 4. Selection edits existing variation
        
        Def: cannot create new traits; only acts on what already exists
        
        Ex: antibiotics selecting resistant bacteria already present
- - - - Mutation:new alleles from DNA change(ex:point mutation creating new flower‑color allele)
        
        Gene duplicationextra gene copies → new functions
        
        Sexual reproduction:reshuffling of alleles(ex:offspring with new trait combinations)
        
        Crossing over:chromosome segments exchanged(meiosis)
        
        Independent assortment:random distribution of chromosomes (ex:different allele combos in gametes)
        
        Random fertilization: random egg–sperm pairing
    - - Discrete characters:single‑gene traits; distinct categories(ex:red/pink/white wildflower colors)
      - Quantitative characters:traits varying along continuum(ex:height, skin color)
      - Nucleotide variability: DNA sequence differences(ex:base‑pair differences between individuals)
      - Geographic variation:differences among populations(ex:caribou herds with distinct traits)
  - - - Same species: individuals capable of interbreeding(ex:Yukon caribou herds)
      - Interbreeding:produce fertile offspring(ex:members of same herd mating)
      - Localized group::living in same area(ex:wildflower population in one meadow)
    - - All alleles at all loci:total genetic content of population(ex:all CR and CW alleles in wildflowers)
      - Fixed allele:only one allele present at locus(ex:all individuals homozygous for same allele)
      - Heterozygosity:proportion of heterozygotes(ex:CR CW wildflowers)
    - - p + q = 1
      - Genotype frequency
      - Phenotype frequency
  - - - No mutation: allele sequences unchanged
      - Random mating:no mate choice bias
      - No natural selection:equal survival/reproduction
      - Large population:minimizes genetic drift
      - No gene flow:no migration of alleles
    - - Baseline for comparison:expected non‑evolving population
      - *Detect evolution:compare observed vs. expected*
      - Medical applications (PKU example):estimate carrier frequency
  - - - Differential reproductive success:some individuals leave more offspring(ex:DDT‑resistant flies increasing)
      - Adaptive evolution:traits improving fitness increase(ex: soapberry bug beak length matching fruit depth
      - Directional, disruptive, stabilizing selection:
        
        Directional:favors one extreme
        
        disruptive selection::favors both extremes
        
        Stabilizing selection:favors intermediate traits
    - - Random allele frequency change:chance events altering gene pool(ex:wildflower allele lost by chance)
      - Strongest in small populations:greater impact of random events(ex:small isolated populations)
      - Founder effect:small group starts new population(
      - Bottleneck effect:sudden population reduction(ex:llinois prairie chickens losing genetic variation)
    - - Movement of alleles:transfer between populations
      - Immigration/emigration:individuals entering/leaving
      - Reduces differences between populations:homogenizes allele frequencies(ex:populations becoming genetically similar)