genbio finals module 8

• Darwin's most famous travel involved a trip to the Galapagos island.
• Darwin wrote and published a book entitled "On the Origin of Species", in which he proposed the now famous theory of evolution by natural selection.
• In 1809, Lamarck published his theory of how organisms changed over time.

  • His main ideas included that through selective use or disuse of organs, organisms may acquire or lose certain trait during their lifetime.
• Theory of use and disuse

  • Organisms could alter the size, shape, or structure of particular body parts or organs by continuously using them in new ways.
  • Example is the giraffe, used to have short neck but there are no supply of foods on the ground so they eat the leaves of trees.
• Theory of disuse

  • states that if ana animal choose not to use its body part, that body part or organ would eventually decrease in size for several generations until it finally disappears.
  • Example is the vestigial limb or spurs structures on snakes. Since snakes doesn't use their feet so the parts became underdeveloped.
• Theory of Inheritance of Acquired Characteristics

  • states that organisms inherited their traits from their parents, and that they also pass them on to the next generation of offspring.
  • example is the trunk of an elephant same as the giraffe.
• Evidence of Evolution

  • Biogeography
  • fossil record
  • homology
  • embryology
  • dna/protein sequences
• Biogeography

  • The study of the distribution of plants and animals on earth.
  • the distribution of organisms in an environment can be used as an important tool for explaining evolution.
  • As observed by Charles Darwin
• Fossil record

  • Contains preserved remains or evidence of ancient organisms.
  • Provides strong evidence of the history of life on earth.
  • They also show how different groups of organisms have changed over time.
• Fact about fossils is that they reveal how life on earth changed from one period of time to the next because they appear in a particular order.
• Fossils of ancient organisms appear on older rocks.
• Paleontologist have found out that almost 99 percent of all species that have lived before became extinct.
• Homology

  • can be found by studying and comparing certain body parts of different animals.
  • "Homologous Structures" means that bone structures that are quite similar but different functions of each organisms to survive in different environment.
• Embryology

  • The early development of various organisms.
  • Different organisms have similar structures during their early embryological development.
  • The shared embryological development of organisms is also responsible for the similar growth of their homologous structures.
  • The comparative embryology among different species suggests that there is common ancestry because all the embryos have similar early developmental stages.
• DNA/Protein Sequences

  • The study of DNA and protein sequence is important for identifying the evolution of organisms on Earth.
  • DNA sequencing is the most advanced tool or evidence for evolution.