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Chapters 22-24 (Evolution-changing traits that arise from a population…

- - - - When species share traits with similar functions because of convergent evolution, whether due to similar environments but not similar ancestry then it is analogous
      - Homologous features while not similar share common ancestry but not necessarily similar function
      - Species that are endemic(uniquely in one place) on islands often are similar to the nearest mainland as opposed to being similar to other isolated islands
      - Darwins theory was built upon two things he observed:
        
        The 2nd observation was that organisms produce more offspring than the environment can support.
        
        Individuals in a population vary in their habitable characteristics.
        
        From this observation he came up with two possible ideas
        
        Individuals that are better suited to their environment tend to leave more offspring than their individuals
        
        Organisms produce more offspring than the environment can support
- - - - Homology-Similarity coming from common ancestry but this does not also include form
        
        Vestigial structures are remnants of features that served a function in the organisms ancestors
- - - - Changes in genetic code can occur when the wrong DNA sequence or recessive alelle that doesn't work is coded
        
        Neutral Variation occurs when a change in DNA sequence doesn't give an advantage or disadvantage
        
        Hardy Weinberg equation-a way to detect evolution in a population through the measure of traits present in a population pq+qp=2pq
        
        Hardy Weinberg Equilibrium-allele and genotypes occur at a constant equilibrium leading to no genetic variation within a population.
        
        Adaptive evolution-a process in which traits that enhance survival or reproduction tend to increase in frequency over time.
        
        Genetic drift is chance events that affect the alleles present in a population, possibly changing it.
        
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        In order for this equilibrium to occur you need 5 conditions
        
        A large population
        
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- - - - Reproductive Isolation - the existence of biological factors that impede members of two species from interbreeding and producing fertile healthy offspring.
        
        Prezygotic Barriers-block fertilization from occuring
        
        postzygotic barriers-contribute to reproductive isolation after the hybrid zygote is formed
        
        morphological species concept-distinguishes a species by body shape and other structural features.
        
        ecological species concept-defines a species in terms of its ecological niche, the sum of how members of a species interact with the living and nonliving parts of its environment.
        
        Allopatric speciation-gene flow is interrupted when a population is divided into geographically isolated subpopulations.
        
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