1. EVIDENCE FOR EVOLUTION (SECTION 8.2)

2. Darwin’s Observations
Page 329

3. THE VOYAGE Collected thousands of specimens.
Collected fossils that resembled existing animals.
Volcanic Galapagos Islands had species similar to S. American mainland species.
Species differed from island to island.

4. DARWIN’S FINCHES Collected on Galapagos.
Beaks modified to suit food source (niche).
Descended from common mainland ancestor.
Different species found on separate islands.

5. Adaptive Radiation of Galapagos Finches
New species branched out from older ones to fill available ecological niches

6. Darwin’s Conclusion All life on earth is related
Currently existing organisms are descendants of past organisms
The mechanism for evolution is natural selection.

7. Fossils Shows numbers of extinct animals
Shows similarities between extinct animals and animals that are alive today
The earth’s layers show a time scale of species and when they appeared on earth (and when they died out)

8. How Fossils Form

9. Transitional Fossils (Missing Links)
Archaeopteryx
link between dinosaurs & birds
Lived 150 million years ago
Discovered 1861, just two years after Darwin published Origin of Species

10. Whale Evolution
Video

11. Tiktaalik Transition from water to land

12. Ida
Darwinius masillae (“Ida”) is the approximately 47-million-year-old common ancestor of anthropoid primates: that is, all monkeys and apes, including humans

13. Biogeography

14. Homologous structures – these are parts of the body that are similar, but have different functions
The flippers of whales, and the wings of birds
All forelimbs of vertebrates have the same pattern of bones
Common ancestry
Divergent evolution

15. Homologous Structures

16. Analogous Structures
Some species of different origins have similar physical structures (convergent evolution)
Example1: the wings of bats and insects
Example 2: the eyes of vertebrates, molluscs (like squid and octopus) and insects

17. Evidence of Divergent & Convergent Evolution
HOMOLOGOUS
ANALOGOUS

18. Vestigial Organs – these are organs or parts that seem to have no function in the living organism, but once had a function in an ancestor
Whales have pelvic bones that do not attach to legs
Remember Lamarck’s theory of disuse?

19. Embryological Development
Embryos of different species develop in almost identical ways.
Human fetus at 8 weeks

20. Biochemistry and DNA
When comparing the DNA sequence of a gene or amino acid sequence of a protein between two species, more similarities are found in species that are more closely related.
Lion photo credit: ucumari Tiger photo credit: digitalART2

21. Comparing DNA or Amino Acid Sequences

22. Cytochrome C oxidase (mitochondrial protein found in all eukaryotes)

23. Cladogram (Phylogenetic Tree)

24. Primate Evolution

25. Direct observation of species change
Bacteria become resistant to antibiotics
Artificial Selection
Plants and animals were “domesticated” for agriculture
Wolves were bred over many generations to become dogs and then bred further to create a variety of breeds

26. Another example of Artificial Selection
Pests become resistant to chemicals.

27. What Evolution is NOT
The theory of evolution is an explanation of the diversity and distribution of life forms on earth. It is not an explanation of the initial origin of life. This is an active area of research called “abiogenesis,” “astrobiology,” or simply origin of life (OOL). It is obviously part of the larger scientific project to understand the universe, but is not fundamental to evolutionary theory.

28. Creationism, sometimes referred to as “creation science” or “intelligent design” is the belief that organisms were placed on this earth by a divine being (God).
It is NOT a scientific theory because it does not follow scientific principles
Scientific theories require evidence, and must be based on NATURAL PHENOMENON
Finding gaps in our knowledge about evolution is a normal part of the scientific process, the existence of these “gaps” and questions does not qualify as evidence that an alternative theory must be correct

29. Many religious organizations do not have a problem with evolution, and it is compatible with their faith and beliefs.
Ask your religious leaders what their thoughts are.
Also see the National Centre for Science Education for a list of statements from a variety of religious groups.
Here’s an excellent lecture by Kenneth Miller

30. HOMEWORK Read Sections 7.1, 7.2 & 8.2 Page 304 #1-9
HIV evolution video