Gen bio geological timescale

• Aristotle

  384-322 B.C.
• Aristotle's views


  • Species are fixed (unchanging)
  • Recognized similarities
  • Arranged life forms on a scale of increasing complexity
  • Scala natura- "scale of nature" "heredity and descent
• Carolus Linnaeus


  • Founder of TAXONOMY-1735 Science of grouping & naming
  • Sought to discover order in the diversity of life "for the greater glory of God"
  • Each creature was special- NO evolutionary link
  • Devised classification system based on morphology (form and structure)
• Binomial Nomenclature


  Naming system that gives organisms a two part scientific name: Genus Canis lupus familiaris species
• • The first is genus name and second is species name
  • It is always written in italics (if typed) or underlined (handwritten)
  • The first letter of genus name is always capitalized
• Taxon


  Classification unit to which organisms are assigned
• Taxon


  • Panthera is a taxon at the genus level
  • Mammalia is a taxon at the class level
• Genus


  Group of closely related species
• Species


  Unique to each kind
• • Modern Taxonomy has added more Kingdoms AND more levels (DOMAINS)
  • Linneaus only used 2 kingdoms (Plants & Animals)
  • Domains are larger than Kingdoms and are based on the differences in ribosomal RNA
• George Cuvier


  Father of Paleontology
• George Cuvier's views


  • Fossils are remains of extinct life forms
  • Catastrophism - boundaries represent floods, droughts, etc. that destroyed many species living at that time
• James Hutton's views


  • Gradualism - Profound changes can result from cumulative effect of slow but continuous Processes
  • Proposed that the Earth was shaped by geological forces occurring over very long periods of time, and is MILLIONS not THOUSANDS of years old
• Charles Lyell's views


  • Incorporated Hutton's ideas into "UNIFORMITARIANISM" - the idea that Earth has always changed in uniform ways
  • Darwin read his book on the Beagle voyage
• Examples of uniformitarianism


  • The reshaping of a coastline by a tsunami
  • Deposition of mud by a flooding river
  • The devastation wrought by a volcanic explosion
  • A mass extinction caused by an asteroid impact
• Thomas Malthus' views


  • Wrote an essay on Population growth
  • Human suffering (disease, famine, homelessness, and war) are consequences to human population increasing faster than food and other resources
• Jean Baptiste Lamarck's views


  • One of first scientists to recognize that living things changed over time and that all species were descended from other species
  • Published his ideas about "Inheritance of Acquired Characteristics" in 1809 - the year Darwin was born
• • What's right with Lamarck's hypothesis?
  • Lamarck was first to develop a scientific hypothesis about evolution and recognize that organisms are adapted to there environment
• • What's wrong with Lamarck's hypothesis?
  • Lamarck didn't know about genes and how traits are inherited
  • Acquired traits are not passed on to offspring
• Charles Darwin


  • British Naturalist
  • Proposed the idea of evolution by natural selection
  • Collected clear evidence to support his ideas
• Charles Darwin's life


  1. In 1831, 22-year old Charles Darwin left England as naturalist aboard the HMS Beagle for 5 year voyage around the world

  2. Mission: Chart the South American coastline

  3. Darwin noticed plants and animals were different from those he knew in Europe

  4. Wrote thousands of pages of observations and collected vast number of specimens

  5. Darwin spent a month observing life on the Galapagos Islands

  6. After Darwin returned to England in 1836, he spent years examining specimens he brought back from voyage and filling notebooks with his ideas

  7. In 1844 he wrote an essay describing his ideas and asked his wife to publish it if he died

  8. In 1858, Alfred Russel Wallace wrote an essay describing his work that summarized the same ideas Darwin had been thinking about for 25 years

  9. In 1859 On the Origin of Species by Means of Natural Selection presented evidence and proposed a mechanism for evolution that he called NATURAL SELECTION
• Descent with modification


  • Suggests that each species has descended with changes from other species over time
  • This idea suggests that all living species are related to each other and that all species, living and extinct, share a common ancestor
• Evidence of evolution


  • Artificial Selection
  • Fossil record
  • Geographic distribution
  • Anatomical homologies
  • Embryology
  • Molecular Homologies
  • Can see Natural selection happen
• Artificial selection


  • Nature provides the variation through mutation and sexual reproduction and humans select those traits that they find useful
• Artificial selection


  • We have selected for and bred cows to produce more milk, turkeys with more breast meat, etc.
• Fossil record


  • Provides evidence that organisms have changed over time
  • If evolution has happened, we should be able to find evidence of evolution in the fossil record AND WE HAVE!
• Fossil record


  • TIK-TAALIK - Intermediate between fish and early tetrapods
• Divergent evolution


  Adaptive radiation
• Homologous structures


  Forelimbs of all mammals share same arrangement of bones that can be traced to same embryological origin
• Evolution explains why certain characteristics in related species have an underlying similarity
• Vestigial organs


  Some homologous structures are vestigial and have no useful function even though they are still present
• Vestigial organs


  • Hipbones and pelvis in whales and boa constrictors
  • Cecum (appendix) in humans
  • Skink legs
• Cecum


  • Most mammals have a pouch between their small and large intestine that contains bacteria to digest plants
  • In humans the cecum is shrunken and unused. It is our appendix
• Embryology


  • Development of vertebrate embryos follows same path
  • Why grow a tail and then lose it?
  • Human EMBRYO has a tail at 4 weeks which disappears at 8 weeks
  • Pharyngeal pouches become gills in fish, parts of throat/ears in human
• Molecular homologies


  Similarities in DNA and protein sequences suggest relatedness
• Molecular homologies


  • Fish, amphibians, reptiles, and most mammals can make their own vitamin C, but humans can't make vitamin C. Without fresh fruit, humans end up with scurvy.
  • Human DNA contains the gene that codes for the enzyme to make vitamin C, but it is nonfunctional.
  • Primates, which includes chimpanzees, orangutans, gorillas, and other apes, also lack the ability to make their own Vitamin C.
• Adaptation


  Any inherited characteristic that increases an organism's chance of survival
• Overproduction of offspring


  Capacity to over-reproduce seems characteristic of all species
• Struggle for existence


  Members of each species must compete for food, space, and other resources
• Survival of the fittest


  Ability of an individual to survive and reproduce in its specific environment