1. Biology 101- Evidence of Evolution
Pick up DARWINS NATURAL SELECTION journal. Begin working on this. EVERYONE NEEDS TO BE IN THEIR SEAT WORKING BY THE TIME THE BELL RINGS!!

2. Sources of Evidence for Evolution
From observations
Biochemistry
From studies of embryology
From the fossil record
From studies of anatomy
From studies of DNA
From Geographic distribution

3. Fossil Structure Fossil- Remains of organisms
Usually found in sedimentary rock
Relative age- “date” fossil based on where it is in rock strata
Absolute dating: measures decay of radioactive elements into stable forms (Carbon-14 and Uranium-238)
Decay rate is steady (half-life)

4. How is Half-life calculated?
How does radioactive dating work?
Since decay is steady, you can calculate how old something is by how much of it is left
Ex: Carbon 14 converts to Carbon 12 when it decays
Decay rate is 5,700 years
If you start with 1 gram of Carbon 14, after 5,700 years there would be ½ gram of it left

5. Archeopteryx
Archeopteryx shows evidence of the evolution of birds from reptiles
There is evidence of feathers (from birds)
There are claws (from reptiles)

6. Evidence from common structures: Similar skeletal organization
Are called Homologous structures- body parts similar in structure but not necessarily in function
Suggests common ancestor- but each adapted to different environments

7. Anatomical studies show..
What are other organisms that have the ability to fly, but have wings very different from those of birds?
Structures like the wings of birds and wings of insects are called…
Analogous Structures- similar in function, but different structures
Do not have a common ancestor, but have evolved with similar adaptations due to similar environments

8. Do these organisms, a bird, mammals and a fish, show analogous structures or homologous structures?
Convergent evolution: results in analogous structures
Different bone structures, but similar functions due to similar environments

9. Do these organisms show analogous or homologous structures?
Many different species evolving from a recent common ancestor would be an example of divergent evolution, all showing homologous structures
Over 70 lemur species evolved from a species that colonized Madagascar less than 60 million years ago

10. Why would this bird have wings if it doesn’t fly?
Structures are so reduced in size that they are vestiges or traces of homologous organs in other species called VESTIGIAL STRUCTURES

11. Anatomical Studies show…
Why does this salamander have eyes if it never sees the light of day?
Human vestigial structures
Why does a whale have a pelvis and femur bone if it has no hind limbs?
Why does a boa have a remnant hind limb?

12. Why do these structures occur?
These structures may be homologous to ones that had a function in the ANCESTORS of these organisms thus suggesting their evolution from this common ancestor.

13. Today’s activities
The Molecular Connection

14. Getting Started: Tues 4/22
EVIDENCE PT 2 NOTES START HERE….

15. Embryology Studies
Even though it may not be apparent during the first stage of development, these 5 organisms are very different at later stages of development and at birth
Why do they look so similar to each other during early development?
Organisms having more similarities during later stages are thought to have a more recent common ancestor

16. Studies of Biochemistry
Humans and chimpanzees have no differences in this amino acid sequence suggesting their close evolutionary relationship
They have a more recent common ancestor than any other two species shown
Human
V-H-T-A-T-A-A-S-D-L-A-T-D-K-R-C-H-E-Y-A
Chimp
Gorilla
V-H-T-A-T-A-A-S-D-L-A-T-D-K-K-C-H-E-Y-A
Horse
V-Q-S-A-L-A-S-G-E-V-H-A-D-K-R-V-R-D-Y-A

17. DNA
The sequence of the nucleotides making up the DNA would also be similar because DNA determines the sequence of amino acids in the proteins
DNA sequences can be used to make “family tree” so that we can see how closely related different species are

18. What is this diagram showing you
What is this diagram showing you? What could be a possible explanation for this?

19. Penicillin patch
Penicillin patches were placed in a bacteria culture. One patch showed growth of bacterial colonies while another one did not. What happened?
Bacteria colony grows

20. Evidence from Geographic distribution
Biodiversity
First suggested evolution to Darwin
Species tend to be more closely related to other species from the same area than to species with the same way of life, but living in different areas
Islands tend to have many endemic species that are closely related to species from the nearest mainland

21. Different Geographic regions, different mammalian “brands”
Flying Squirrel from North America
Sugar Glider from Australia
Different Geographic regions, different mammalian “brands”

22. Has and Does Evolution Occur?
Scientists do not dispute that evolution does occur. Evolution is a fact.
How evolution occurs is not completely understood.
Charles Darwin explained how evolution occurred through natural selection. Natural selection is a well documented theory uniting all of biology.
Modern evolutionary theory uses ideas of genetics, particularly mutations, to help explain how evolution may occur

23. Today’s Agenda Embryological Evidence
Molecular Connection- DNA analysis (front table)
Complete any work you have not already finished.