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Evolution - Coggle Diagram

- - - - Fitness: Ability to survive & reproduce based on adaptive traits.
        
        Heritability Requirement for Evolution
        
        Traits must be genetic to be inherited.
        
        Acquired traits (e.g., muscle growth, injuries) are not heritable.
      - HL
        
        Types of Natural Selection
        
        Directional selection: Favors one extreme (e.g., long giraffe necks).
        
        Disruptive selection: Favors both extremes (e.g., large & small beak sizes in finches).
        
        Stabilizing selection: Favors the intermediate (e.g., human birth weight).
  - - - Intraspecific competition: Individuals of the same species compete for resources.
  - - - Predation pressure influences coloration.
  - - - Gene pool: All genes & alleles in a population.
      - Allele Frequencies in Geographically Isolated Populations
        
        Allele frequencies vary between isolated populations.
        
        Changes in Allele Frequency via Natural Selection
        
        Natural selection changes allele frequency based on heritable traits.
        
        Population in Equilibrium
        
        Hardy–Weinberg Equation
        
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        Hardy–Weinberg Equilibrium Conditions
        
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        Neo-Darwinism: Modern synthesis of natural selection & genetics.
        
        Use databases to analyze allele distributions.
        
        Example: Sickle cell allele (HbS) is common in malaria-endemic regions.
- - - - Artificial Selection & Human Influence
        
        Artificial selection: Humans select traits in crops & domesticated animals.
        
        Example: High-yield wheat, faster-growing livestock.
        
        Unintended selection: Antibiotic resistance in bacteria (natural selection).
  - - - Homologous structures: Same ancestral origin, different function.
      - Example: Pentadactyl limb (e.g., human hand, bat wing, whale flipper).
    - - Analogous structures: Same function, but different evolutionary origins.
        
        HL
        
        Adaptive Radiation
        
        Adaptive radiation: One species diverges into multiple species, filling different ecological niches.
        
        Increases biodiversity by reducing direct competition.
        
        Example: Darwin’s finches evolved different beak shapes for feeding specialization.
      - Example: Wings in bats (mammals) & birds (reptiles) evolved separately.
- - - - No two individuals are identical in all traits.
      - Complex variation patterns → Basis for classification.
    - - Morphological species concept (Linnaeus):
        
        Species classified based on shared physical traits.
    - - Genus (capitalized) + species (lowercase).
      - Example: Homo sapiens.
      - Species in the same genus share traits.
    - - Species = Organisms that breed & produce fertile offspring.
      - Challenges:
        
        Asexual organisms.
        
        Hybrid species (e.g., ligers).
        
        Fossil species (no reproduction data).
      - HL
        
        Challenges in Applying the Biological Species Concept
        
        Asexual species (e.g., bacteria) do not breed, making the concept ineffective.
        
        Bacteria exchange genes via horizontal gene transfer, blurring species boundaries.
    - - Diversity in Chromosome Numbers
        
        Different species have different chromosome counts.
        
        HL
        
        Chromosome Number as a Shared Species Trait
        
        Species generally have a fixed chromosome number.
        
        Hybrid sterility occurs if parents have different chromosome numbers.
        
        Example: Mules (horse × donkey) are sterile due to mismatched chromosomes.
        
        Humans: 46 chromosomes vs. Chimpanzees: 48 chromosomes.
        
        Diploid cells have an even number of chromosomes.
      - Karyotyping & Karyograms
        
        Karyotyping classifies chromosomes by:
        
        Banding pattern.
        
        Length.
        
        Centromere position.
        
        Hypothesis: Human chromosome 2 formed by fusion of ancestral chromosomes 12 & 13.
      - Unity & Diversity of Genomes Within Species
        
        Genome = All genetic information in an organism.
        
        Diversity of Eukaryote Genomes
        
        Genome size varies by total DNA amount.
        
        Larger variation between species than within species.
        
        Comparison of Genome Sizes
        
        Extract data from genome databases.
        
        Compare genome size vs. organism complexity.
        
        Current & Future Uses of Whole Genome Sequencing
        
        Faster & cheaper genome sequencing.
        
        Current use: Studying evolutionary relationships.
        
        Future potential: Personalized medicine (tailored treatments).
        
        Same species share most of their genome.
        
        Variation from single-nucleotide polymorphisms (SNPs).
      - HL
        
        Identifying species
        
        Developing a Dichotomous Key for Local Species
        
        Students should engage with local flora or fauna to create a key.
        
        Dichotomous keys classify organisms based on observable traits.
        
        Environmental DNA (eDNA) & Barcoding for Species Identification
        
        eDNA analysis rapidly identifies species in a habitat.
        
        DNA barcoding: Uses short genetic sequences to classify organisms.
        
        Useful for studying biodiversity & detecting rare species.
    - - Result from reproductive isolation
        
        Reproductive isolation prevents gene flow → Leads to speciation.
        
        HL
        
        Hybridization Barriers
        
        Pre-zygotic barriers:
        
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        Post-zygotic barriers:
        
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        Example: Mules (horse × donkey) are sterile hybrids.
        
        Abrupt Speciation in Plants via Hybridization & Polyploidy
        
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      - Congo River separated bonobos & common chimpanzees → Divergent evolution.
        
        New species arise only by splitting of existing species.
        
        Increases biodiversity (speciation adds species, extinction reduces them).
        
        Gradual change within a species ≠ Speciation.
        
        HL
        
        Types of speciation
        
        Sympatric speciation: No physical separation, but reproductive isolation occurs due to:
        
        Behavioral differences (e.g., different mating calls).
        
        Allopatric speciation: Geographic barrier (e.g., mountains, rivers) separates populations.
        
        Temporal isolation (e.g., breeding at different times).