Evolution

• Evolution

  Happens over millions of years
• Darwin


  "evolution happens for survival"
• Sources for Evidence of Evolution

  • Organisms inhabiting the earth have changed over time, their structures, traits and abilities allowed them to adapt and survive in their environment
  • Fossil records
  • Anatomy and morphology
  • Embryonic development
  • Biochemistry
• Fossil


  Traces of organisms that lived in the past and preserved by natural process/catastrophic events. Remains of organisms which include bones, shells, teeth and feces embedded in rocks, peat, resin and ice
• Paleontologist


  Scientist that specializes in fossils
• Types of Fossils

  • Fossils found in sedimentary rocks (from the hard parts of the organisms)
  • Imprint/Impression (shallow external molds left by animal or plant tissues with little or no organic materials present)
  • Compression (shallow external molds left by animal or plant tissues with more organic material)
• Determining the Age of Fossils

  1. Paleontologists make initial estimates of the age through the position in the sedimentary rocks

  2. Relative Dating (a method used to determine the age of the rocks by comparing them with the rocks in the other layer)

  3. Radiometric Dating (a method used to determine the age of rocks using the decay of radioactive isotopes present in rocks)
• Invertebrates

  One of the first and oldest organisms that lived on earth
• Radioactive decay

  C (Carbon), Rn (Radon), Ra (Radium), U (Uranium)
• Plants and animals that are still alive constantly replace the supply of C in their body and the amount of C-14 in their body stays the same
• When an organism dies, C-14 starts to decay
• Geologic Time Scale

  Shows the major events in the Earth's history, shows the appearance of various kinds of organisms in a particular period of time on earth
• Era


  The largest division of Geologic Time Scale, namely Precambrian, Paleozoic, Mesozoic and Cenozoic. Each era is further divided into period
• Anatomy


  The study of the parts and structure of organisms
• Morphology


  The study of a specific structures and forms of organisms
• Homologous structures

  Structures from different species which have similar internal framework, position & embryonic development. Perform different functions in the species in different environment, or it may have the same origin but different functions
• Homologous structures

  • Forelimbs of dog, bird, lizard and whale, which are structurally the same, but functionally different
• Analogous structures

  Structures of unrelated species may evolve to look alike, because the structure is adapted to similar function
• Physiology

  The study of functions of structures
• Divergent evolution


  Splitting of an ancestral population into two or more subpopulations that are geographically isolated from one another. Homologous structures are a strong indicator that the organisms evolved from common ancestors
• Convergence

  Increase in similarities among species derived from different ancestors because of similar adaptation to similar environment. Analogous structure - unrelated organisms from different ancestors develop similar function
• Embryo

  Early stage of development in organisms
• The embryo of fishes, salamanders, lizards, birds, cats and humans are similar during the first stage of their embryonic development; and have several homologous structures that are not present when the organisms are adults
• Biochemistry


  Greater the similarity in amino acid sequence, the closer the relationship of the organisms having a high chance they could probably have a common ancestor
• Species Pairings and Number of Differences in Amino Acids

  • Human - Chimpanzee (0)
  • Human - Fruit fly (29)
  • Human - Horse (12)
  • Human - Pigeon (12)
  • Human - Rattlesnake (14)
  • Human - Red Bread Mold (48)
  • Human - Rhesus Monkey (1)
  • Human - Screwworm Fly (27)
  • Human - Snapping Turtle (15)
  • Human - Tuna Fish (21)
  • Human - Wheat (43)
  • Fruit Fly - Dogfish Shark (26)
  • Fruit Fly - Pigeon (25)
  • Fruit Fly - Screwworm (2)
  • Fruit Fly - Silkworm Moth (15)
  • Fruit Fly - Tabaco Hornworm Moth (14)
  • Fruit Fly - Wheat (47)
• Lamarck's Theory of Evolution

  Organisms change in response to their environment. Their ability to survive helped them develop characteristics necessary for them to adapt in a given environment
• Theory of Use and Disuse

  Organs not in use will disappear while organs in use will develop
• Theory of Use and Disuse

  • Giraffes before have short necks, but because of the need to survive and to reach tall trees for food, they kept stretching their necks until these became longer and able to reach taller trees
• Theory of Acquired Characteristics

  Acquired characteristics were inherited by their offspring and propagated by the next generation
• Darwinian Theory - Theory of Natural Selection

  Natural selection favored the survival of giraffes with longer necks that could feed on taller trees that were available, thus giraffes with short necks were eliminated due to lack of accessible food supply
• Darwinian Theory - Theory of Natural Selection

  • In Galapagos Island, Darwin observed that finch species have different beak structures for different food types which somewhat relates to the abundance of certain finch species in an island
• Darwin's Theory


  Creating offspring to evolve own gene pool
• Incest

  Reusing of gene pool, not having diversity and the recessive gene is inherited by the offspring resulting them to have weaker immune systems and diseases
• Selective breeding


  Farmer identifies and selects the best and desirable trait to propagate, like in natural selection, environmental factors promote the survival of the fittest and eliminates the less fit
• Fitness


  Ability of an organism to survive and produce offspring
• Variation


  Different individuals in a population possess different characteristics and abilities, which increases the chance of survival of living things
• Organisms with the best and desirable traits would likely adapt to environmental changes & may gradually become better suited to survive in a given environment
• Mating between surviving populations of the same species

  May shift the abundance of a new breed of organism because of mutation, gene combination and natural selection thus leads to speciation
• Speciation


  Group within a species separates from other members and develops its own unique characteristics
• Internal Framework

  The underlying structure or skeleton of the part.