5 LESSON_Q3

• Organisms inhabiting the earth have changed overtime, their structures, traits, and abilities allowed them to adapt and survived in their environment
• Fossils


  Traces of organisms that lived in the past and were preserved by natural process or catastrophic events
• Paleontologist


  A person who studies fossils
• Most fossils were commonly found in sedimentary rocks. They were from the hard parts of the organism like woody stem, bones, or teeth
• Compression


  The side of an imprint fossil with more organic material
• Impression


  Shallow external molds left by animal or plant tissues with little or no organic materials present
• Determining the age of fossils

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

  2. Fossils found in the bottom layer are much older than those found in upper layer of rocks
• Geological Eras


  • Cenozoic
  • Mesozoic
  • Paleozoic
• Geological Periods


  • Quaternary
  • Tertiary
  • Cretaceous
  • Jurassic
  • Triassic
  • Permian
  • Carboniferous
  • Devonian
  • Silurian
  • Ordovician
  • Cambrian
• Geologic Periods


  • Silurian
  • Ordovician
  • Cambrian
• Compression


  One side of an imprint or impression with more organic material
• Impression


  Shallow external mold left by animal or plant tissues with little or no organic materials present
• Determining the age of fossils

  1. Position in sedimentary rocks

  2. Amount of radioactive carbon-14
• One way scientists determine the age of fossils is by checking the amount of radioactive carbon-14 in the fossil
• Carbon-14 breaks down or decays to form nitrogen-14 at a constant rate (half-life of 5730 years)
• Relative Dating


  Method to determine the age of rocks by comparing them with the rocks in other layers
• Radiometric Dating


  Method to determine the age of rocks using decay of radioactive isotopes
• Carbon Dating


  Used to tell the age of organic materials
• The Geologic Time Scale shows the major events in the Earth's history and the appearance of various organisms
• Era is the largest division of the Geologic Time Scale, further divided into Periods
• Homologous structures


  Structures from different species which have similar internal framework, position, and embryonic development
• Analogous structures


  Structures of unrelated species that evolve to look alike due to adaptation to similar function
• Divergent evolution


  When a population is split into two groups by a geographic barrier, causing each group to develop different traits
• Convergent evolution


  Increase in similarities among species derived from different ancestors as a result of similar adaptation to similar environment
• Embryology


  Study of the development of the anatomy of an organism to its adult form
• The greater the similarity in amino acid sequence, the closer the relationship of the organisms
• Definitions


  • vestigial structure
  • homologous structures
  • DNA sequence
  • fossil record
  • embryology
• According to evolutionist, the best test to show the relatedness of two organisms are the similarity in their genomic DNA
• Embryonic development of bird and human show similarities during stage 1
• The studies of differences and similarities between different things are called comparative anatomy
• Homologous structures are anatomically the same structure but have different function
• In convergent evolution, organisms that are closely related develop similar characteristics due to living in the same environment
• Embryology


  Study of the early development of fetuses
• Organisms having the same bone makeup

  • Different organisms; has documented that in early stages of development, dogs, pigs, and humans resemble each other
• Structures that have reduced in size

  Because they no longer serve an important function
• Comparative anatomy


  Studies of differences and similarities between different things
• Homologous structure


  Anatomically same structure but different function
• Geologic time scale


  Shows the major events in the Earth's history and the appearance of various kinds of organisms in a particular period of time on earth
• Importance of comparative anatomy in the study of evolution

  • It helps determine evolutionary relationships between organisms and whether or not they share a common ancestors
• Homologous structures


  Share a common ancestry but not necessarily a common function