Evidence for Evolution

1
Evidence for Evolution

• Evolution on trial

2

• Earth is 4.6 billion years old and the oldest
  evidence of life is 3.6 billion years old.
• If this mechanism of change has been shaping the
  organisms on this planet, then there should be
  evidence of it occurring
• 5 major types of evidence used to support the
  theory of evolution.

3
1. Fossil Record

• Skeletons, bones, impressions, etc. of organisms
  no longer found living on the planet.
• Radiometric and relative dating suggests life is
  billions of years old
• Activity
• The older the fossils the more simple and the
  greater the differences between existing
  organisms
• Incomplete and includes inferences

4
2. Biogeographical

• The study of the geographic distribution of
  organisms
• Islands of the world have species found no place
  else. (13 different species of finch on
  Galapagos, aquatic iguanas, Hawaiian
  honeycreepers, etc.)
• Marsupials found in both Australia and S.
  America. Few placental mammals in Aus many in S.
  America. Results in a wide diversity of
  marsupials in Australia and low diversity of
  marsupials in S. America
• Organisms that are similar on different
  continents are that way b/c adapted to similar
  ecosystems

5
(No Transcript)
6
3. Anatomical

• Outside appearance of body parts of similar
  categories of organisms may look and function
  differently
• If internal structures are examined lots of
  similarities exist.
• Ex. Forelimbs in vertebrates
• Homologous Structures Structures in different
  species that are similar in makeup, and may have
  different functions.
• Wings of bat, forelimbs of dog

7
3. Anatomical Cont.

• Analogous Structures Structures in different
  species that have different makeup but have same
  function.
• Wings of bat and wings of bee
• Vestigial Structures Any structure that is
  reduced in function.
• Results in reduction of size. (ex. Human Appendix
  / wisdom teeth, whale pelvic bones, ostrich
  wings, dew claw on dogs and cats.)

8
(No Transcript)
9
(No Transcript)
10
(No Transcript)
11
4. Embryological Development

• The stages of development from zygote to embryo
  are the same for all animals.

12
5. Genetic Comparisons

• Comparing the base pairs of similar genes,
• and/or amino acid sequences of similar proteins
  from different organisms
• The more similarities the closer related.
• 60 of human genes are fundamentally the same as
  fruit fly genes.
• 90 the same as mice
• 96 similar to chimpanzees
• All humans are 99.9 the same genetically

13
(No Transcript)