Patterns Of Evolution

Patterns Of Evolution

1. Mechanisms

   • Natural Selection
     • Environmental Pressures
     • Sudden Changes in Condition
     • Bottleneck
       • Sharp reduction in population due to environmental effect
     • Genetic Drift
       • Change in the frequency of alleles due to random sampling
     • Founder effect
       • Creation of a new population with a few individuals from a larger population
   • Mutations
     • Gametic
       • Occurs in the gametes meaning that they will be passes on
     • Point
       • Mutation on a single nucleotide
         • Substitution
           • This is the least harmful as there is a high chance of replacing the same amino acid
         • Insertion
           • This results in a frame shift which is the most harmful mutation
         • Deletion
           • It deletes one nucleotide from
     • Chromosomal
       • Anueploidy
         • Addition of a chromosome to one set
           • Monosomy
             • Lack of one chromosome
           • Disomy
             • Humans its in vaild
           • Trisomy
             • The pressense of an extra chromosome
       • Polyploidy
         • Addition of a whole set of chromosomes
           • Triploid
             • Three sets of chromosomes
           • Tetrapliod
             • Four sets of chromosomes
           • Pentapliod
             • Five sets of chromosomes
         • Alloploidy is between two species
         • Autopolidy is between one species
       • Block
         • Involves a blocks of genes not just individual bases
           • Inversion
           • Duplication
           • Translocation
           • Deletion
     • Somatic
       • Occurs in the body cells meaning they won't be passed on
   • Prezygotic vs Postzygotic barriers to reproduction(Gene flow)
     • Prezygotic
       • Geographic Isolation
         • Prevent two organisms from crossing paths even accidentall
       • Habitat Isolation
         • Make it unlikely that paths will cross even given the occupation of the same general geographical range
       • Temporal Isolation
         • Make it unlikely that two organisms will be unlikely to be receptive mate at the same time of year
       • Behavioral Isolation
         • Preventing two orgaisms to mate even if they are temporal
       • Mechanical Isolation
         • Prevents to organisms from mating even if they "want to"
       • Gametic Isolation
         • Blocks conception even of they mate the egg wont join with the sperm
     • Postzygotic
       • Hybrid Zygote Abnormality
         • When two different organisms mate they can create a hybrid zygote which often don't make it past germination and they never develop normally
       • Hybrid Infertilality
         • Don't develop normally and are often sterile
       • Low Hybrid Vitality
         • Most die before reaching reproductive age

2. Patterns

   • Alopatric Speciation
     • speciation that occurs when biological populations of the same species become vicariant — isolated from each other to an extent that prevents or interferes with genetic interchange
   • Sympatric Speciation
     • Where new species evolve from a single ancestor but inhabit the same geographic region
   • Punctuated Equilibrium
     • Indicating that there is little evolutionary change to a species for their history
   • Gradulism
     • Very gradually, over a long time, the population changes. Change is slow, constant, and consistent.