Please enable JavaScript.

Coggle requires JavaScript to display documents.

Evolution (Types of Selection (Artificial Selection (Selective pressure…

- - - - More and more individuals will receive the allele over time, and the individuals will form a population better adapted to their environment
    - - A trait may be advantageous right now, but in another situation it will be irrelevant
  - - - Dog breeders mix dogs together for desirable traits
      - Food crops are also selectively bred
- - - - Events that wiped out entire species at a time
- - - - Similar animals in places far from each other, the continents must have been together
  - - - Structures that have similar structural elements and origin but may have a different function
        
        Frogs, bats, and horses have similar bone structures in their front limbs, but they have different functions
        
        Hair in mammals is homologous
      - May have similar number of bones, muscles, ligaments, tendons, and blood vessels
      - Similar because they were inherited from a common ancestor
    - - Structures of organisms that do not have a common evolutionary origin but perform similar functions
        
        The wings of insects, birds, and flying mammals are similar in function, but not in structure
  - - - Similarities between embryos in closely related groups, suggesting a common ancestor
  - - - Similar DNA sequences must have been inherited from a common ancestor
      - Thanks to DNA sequences, scientists have discovered that dolphins are related to cows
- - - - Mechanical
        
        Certain species may be anatomically incompatible
      - Gametic
        
        If the gametes from different species do not meet, it is very unlikely they will form a zygote
    - - Behavioural
        
        Any special signals or behaviours that are species specific prevent interbreeding of closely related species
        
        For example, a mating call specific to one bird species
      - Temporal
        
        Two species may mate at different times of the year, the day, etc.
      - Ecological/Habitat
        
        Two species live in the same general region, but not the same habitat
        
        Certain garter snake species prefer the water, others prefer meadows
  - - - When two species can produce a hybrid offspring, it is often sterile, and can't reproduce
        
        Mules have reproductive barriers and can't reproduce
    - - Genetic incompatibility of the hybrid zygote during development, prevents normal mitosis after fusion of nuclei in the gametes
    - - When first-generation hybrids are viable and fertile, when the hybrids try to mate with any animal, the next generation is sterile or weak
  - - - Chromosomal changes in plants can cause this
  - - - Each population will adapt differently and eventually become a new species
- - - - Gene flow is very common between grey wolf populations
  - - - In caribou herds, males compete by sparring with their antlers
    - - It doesn't directly affect the distribution of alleles, but homozygous genotypes can lead to more harmful recessive alleles
        
        Purebred animals often face more issues like infertility, infant mortality, and deformations
      - Flowers that self-fertilize are an example
  - - - The founder effect is when a change in a gene pool occurs when a few individuals start a new isolated population
        
        The different finches in the Galapagos came from a species of birds that flew over from the mainland
      - The bottleneck effect is changes in gene distribution that results from a rapid decrease in population size
        
        It is often seen after natural disasters, or when species are close to extinction
- - - - A structural adaptation in which a harmless species resembles a harmful species in coloration or structure
    - - An arctic bird is white to blend in with the snow
  - - - Birds fly south in the winter to escape the cold
  - - - Allows animals to survive harsh winters
- - - - Variation in one species