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Evolution - Coggle Diagram

- - - - Abiotic: Drought, flood, temperature fluctuation
      - Biotic: Parasites, competition, invasive species
    - - Directional: An extreme phenotype is favored over other phenotypes and allele frequency continuously shifts towards that direction, e.g. short vs. tall giraffes, white vs. black pepper moths.
      - Disruptive: Extreme values for a trait are favored over intermediate values and the variance of the trait increases until the population has diversified into two distinct groups/species, e.g. Ground Finches with medium-sized beaks nearly become extinct during persistent drought.
      - Stabilizing: Genetic diversity decreases as the population stabilizes on a common trait value, e.g. zebra stripes, number of eggs laid by a bird.
  - - - Traits that become more common are those that enable an organism to survive, successfully mate, and reproduce.
      - Sexual Dimorphism: A marked difference between males and females.
    - - Performed to achieve desired or advantageous characteristic in offspring.
- - - - Hardy-Weinberg Principle: Changes in genotypic and allele frequencies indicate genetic variability in a population - a measure of microevolution.
      - Criteria: The principle specifies the conditions under which there would be no change in intergenerational frequencies; the conditions in which the population is said to be in Hardy-Weinberg equilibrium.
        
        No Mutations: Alleles in the gene pool cannot change.
        
        No Gene Flow: No exchange of genes between populations; no migration.
        
        Random-Mating: Females cannot select a male with a particular genotype.
        
        No Natural-Selection: No genotype can have reproductive advantage over another.
        
        Large population size
    - - Carl Linnaeus defined species as a group distinguished by morphological differences from other life forms. The modern day definition focuses on genetics and biochemistry.
      - Species: Groups of actually or potentially inbreeding natural populations which are reproductively isolated from other groups. They share a gene pool and breed to produce viable, fertile offspring.
        
        Mechanisms for Preventing
        Different Species from Mating
        
        Reproductive: Isolating mechanisms dependent on the reproductive incompatibility of biochemical, structural, and behavioral traits that a species presents.
        
        Postzygotic: Isolating mechanisms that prevent viability, survival, and fertility of offspring.
        
        Hybrid Inviability: The embryo develops and is born, however hybrid is weak and will not reproduce, e.g. lions and leopards will produce hybrids with a short life expectancy and death before reaching sexual maturity.
        
        Hybrid Infertility: Hybrids develop and mature normally, however, are sterile and do not produce viable gametes, e.g. mules possess intermediate phenotypic characteristics originating from a cross between a horse and donkey, however, are sterile.
        
        Zygotic Mortality: Fertilized zygotes die before birth due to chromosomal incompatibility, e.g. sheeps and goats can mate, but the zygote is not viable.
        
        Prezygotic: Isolating mechanisms that prevent mating.
        
        Mating Prevention
        
        Ecological Isolation: Species that occupy separate niches and habitats that do not meet to court or mate, e.g. the hoary marmot lives in alpine meadows while the groundchuck lives in lower fields.
        
        Temporal Isolation: Potentially compatible species mate or flower at different seasons or times, e.g. geographic ranges of Western or Eastern skunk do not interbreed given that they mate during late summer and winter respectively.
        
        Behavioral Isolation: Distinctive mating and courtship rituals with the objective of attracting a female mate will note be recognized by different species, e.g. mating dances, songs, preferences, and pheromonal types.
        
        Fertilization Prevention
        
        Mechanical Isolation: Structural differences in reproductive organs prevent copulation and penetration, e.g. Bush babies, small arboreal primates, are divided into small species based on compatibly shaped genitalia.
        
        Gametic Isolation: Prevents fertilization at the molecular level; egg and sperm fail to fuse, female immune system identifies sperm as foreign and responds with attack, or sperm/pollen may not be adapted to the environment of the female reproductive tract, e.g. aquatic species release gametes into water and fertilization takes place externally.
- - - - e.g. 13 species of finches emerged as a result of the variety of food sources which could be exploited by finches of diverse beak size or feeding behavior.
  - - - e.g. Sharks and dolphins developed similar streamlined bodies adapted for life as a high-speed aquatic carnivore; natural selection favored similar body shape. Sharks are cartilaginous fish while dolphins are mammals.
    - - The Madagascar long-spurred orchid is pollinated by a hawk moth whose tongue is 30 cm long - dependent on the flower as a source of nectar.
      - The Agouti develops more powerful jaws and teeth as the Brazil nut evolves a harder, more protective shell; an evolutionary arms race.
    - - e.g. Ontario has 20 species of closely related rodents, e.g. red squirrels, chipmunks, porcupines, beavers, etc., with unique characteristics that enable flourishment in their environment and minimize interspecific competition.
- - - - Panspermia: Proposes that life originated from materials that came to earth from space
      - Endosymbiotic Theory: Proposes that the mitochondria and chloroplast in eukaryotic cells were once aerobic bacteria (prokaryote) that were ingested by a large anaerobic bacteria (prokaryote).
        
        Evidence: :arrow_right: Mitochondria and chloroplasts have their own DNA loops, their cell membranes are strikingly similar to those of bacteria, and organelles replicate independently.
      - Primary Abiogenesis: Proposes that life originated from non-living matter.
        
        Evidence: :arrow_right: Urey and Miller created an apparatus to model the early Earth - combining water ammonia, methane, and hydrogen gases, exposing the mixture to electrical sparks to simulate conditions and yielding urea, amino acids, aldehydes, and carbolyxic acids after one week.