Please enable JavaScript.

Coggle requires JavaScript to display documents.

Chapter 18 - Population Genetics And Evolution - Coggle Diagram

- - - - Factors that cause the gene pool to change
        
        Mutations- causes existing alleles decrease and new alleles increase
        
        Accidents- events to which an organism cant adapt
        
        accidents can affect in many ways
        
        if area of accident has same gene frequency as gen. pop. alleles are eliminated w/ same proportions a
        
        if individual w/ unique allele is killed that allele is wiped out
        
        If area has one allele more frequent that allele is affected more and thus frequency of that allele is altered
        
        many types of accidents
        
        volcanic eruption
        
        droughts
        
        floods
        
        hailstorms
        
        Artificial Selection - process of humans intentionally changing allele frequency in a gene pool
        
        examples include selective breeding of crops and animals
        
        plants and animals are bred to have desirable traits such as disease resistance
        
        Natural Selection - individuals most adapted to an environment survive (survival of the fittest)
        
        2 conditions must be met before this can occur
        
        Population must make more offspring than can possibly grow and survive
        
        Progeny must differ from each other in their types of alleles
        
        Situations in which natural selection does not operate
        
        if adaptation to condition is impossible
        
        cant operate if all individuals are identical
        
        universal surivival
        
        Multiple Selection Pressures
        
        loss of individuals and reduced reproduction not caused by a single factor
- - - - two regions are reproductively isolated if alleles from one region do not reach another
        
        Abiological reproductive barriers are physical, nonliving barriers that prevents two populations from exchanging genes
        
        speciation that results from this is called allopatric or geographic speciation
        
        Biological reproductive barriers are any biological phenomenon that prevents successful gene flow
        
        include flower shape, fragrance, color, etc.
        
        speciation from this is sympatric speciation
        
        prezygotic isolation mechanisms are those that prevent pollination or fertilization
        
        postzygotic internal isolation barriers are those that arise when two or more subpopulations become to different to breed
        
        hybrid sterility occurs when two populations interbreed but the offspring is infertile
        
        Hybrid inviability occurs when a zygote or embryo dies early in development due to incompatibility
      - Adaptive radiation is a type of divergent speciation in which a species rapidly diverges into many new species in a short period of time
    - - Movement of alleles physically through space is called gene flow and it occurs in many ways
        
        Seed dispersal
        
        Vegitative propagation - mobile pieces that produce vegitatively
        
        pollen transfer
- - - - Second atmosphere was hydrogen sulfide, ammonia, methane and water. This second atmosphere was a reducing atmosphere
    - - Uv and gamma radiation, heat, and electricity
    - - There simply was no time limit
  - - - This was possible to due to pools at the seaside in which monomers became highly concentrated
      - Monomers may have concentrated in particles of clay as well