Evolution

Evolution

1. Change in genetic composition of a population from generation to generation

   • Macroevolution
     • decent w/ modifications
   • Microevolution
     • change in the genetic makeup of a popultaion

2. Example

   • Self-Decorating Catipillar

3. Charles Darwin

   • The Orgin of Species
     • unity of life, the diversity of life, the match between organisms & their enviroments
       • Descent w/ Modifications
         • descendants of ancestral organisms lived in various habits
         • it varies in traits in order to survive & live their life
         • Natural Selections
           • Artifical Selections
             • We decide who is allowed to mate
               • Example
                 • In a liter of dogs, ones that have certain desirable characteristics( loyalty, speed, gentleness) are bred w/ others of similar characteristics
                   • it doesn't always produce favorable results
                     • but this is why we have so many breeds of dogs XD
             • Observation 1: Differences in traits that can be passed down as various alleles in the DNA
               • Observation 2: All species can produce more offspring than their enviroment can support and many of those offsprings fail to survive & reproduce
                 • Inference 1: If there's genetic variation, the ones w/ the best chance of survival are ones that are best adopted to their particular eniroment
                   • Inference 2: The individuals who are able to survive are most likely to pass down their traits over generations
                     • Diversity in populations is essential to survival in changing eniroments
                       • RECAP: Natural Selection
                         • Overtime, Natural Selection can increase the match between organisms & their eniroment
                           • If an enviroment changes or an individual moves to a new habit ~a new species might happen
                           • The individual who is adaptable to change (environment) will pass down their survival skills & survive
                           • DNA of an individual can mutate, but evolution can change the genetic makeup of a population
                           • For a trait to be influenced by natural selection, it must be hertable and it must vary in the population
                             • Natural Selection cannot produce new traits. It is generally due to random mutaion
                           • Fitness is a moving target. What traits are ideal will depend on timing & geography
       • Homology
         • Similarities among different organisms
         • Over time individuals face different environment conditions
           • Related species can have the same characteristics, but they could function differently
             • Example: Mammalian Forelimps:
               • constructed from the same basics skeletal elements
                 • large bones
                 • 2 simaller bonces
                 • 5 dgitits
                 • even smaller bones
           • Homologous Structures
             • Structures in different species that are similar because of the common ancestry
               • Early Stages
                 • All vertebrate embryos have a tail & pharyngeal arches
                   • The results vary in diff. functions
                     • fish = gills
                     • throat = humans & other mammmals
                       • Convergent Evolution
                         • Similar in appearance of function. This is due to Natural Selection favoring similar characteristics along separate lineages
                           • Analogous Features
                             • ~have similar function, but not a common ancestry, and no similar functions
                               • How do we tell the diff. between homologous & analogous?
                                 • examination of the DNA

4. Linnaeus is responsible for the hierachical system: kingdom,phyluim, class, order, family, genus, and species

   • Linneaus grouped orgainisms based on structure similarities
     • Example
       • Strata "new layer" covering the old ones
         • new fossils covering the old ones( layers of a mineral or a rock)
           • Paleontology
             • study of fossils
               • example: the older stratus are not similar to the current life forms
     • Evolution Technique
       • use & discuise
         • inheritance of acquired characteristics that an organism could pass changes to its offspring
           • Example
             • 1.Giraffes varied in neck length in the ancestral popultaions
               • 2. Giraffes who have longer necks have a greater chance of survival
                 • Cuz they could reach the food
                 • 3. Longer necked giraffes passed down their characteristics of the next generation of giraffes

5. Fossil Record

   • Patterns of evolution
     • Shows the past organisms diff. from present day organisms & many species have become extinct
       • Evolutionary changes that occured in various groups of organisms
   • ~Cataceans evolved from terrestrial mammals fossil documents shows the reduction over time in the pelvis & hind limb bones of extinct ancestry
     • Fossil record shows that over time descent w/ modifications produced huge diff. among related groups of organisms & the results in the diversity of life

6. Biogeography

   • The geographic influences of organisms
     • Continental drift & the slow movement of Earth's continents over time
       • Example
         • Some islands have plants and animal species that are not found anywhere around the world
           • Darwin's explanation
             • That most islands species are closely related to species from the nearest mainland or neighboring island
             • It gave rise to new species as they adapt to their new environment
             • 2 Islands w/ similar environments in distant parts of the world tend to relate to species near the mainland
             • Example:
               • The high concentration of marsupial species in Australia

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