1. Evidence of Evolution

2. What evidence do we have that life has evolved gradually from simple life forms to complex life forms over millions of years?

3. There are 4 major types of Evidence that Evolution has occurred.
1. Fossil Evidence
2. Comparative Anatomy and Vestigial Structures
3. Similar Embryonic Development
4. Biochemical similarities

4. Evidence of Evolution
Fossil Evidence

5. What is a fossil?
The preserved or mineralized remains (bone, tooth, or shell) or traces (footprints, burrow, or imprint) of an organism that lived long ago.
Dinosaur fossil - (bone)
Ammonite fossil (shell)

6. Fossils come in many forms
Shark teeth
Dinosaur
footprint
Imprint of fish

7. Fossils are very old Trilobite fossils Stingray fossil
445 million years ago
Stingray fossil
95 million year old
Bird egg fossil
1 million years old
Beetle fossil
50 million years old

8. How do We Know How Old things Are?
Carbon dating half –life of carbon 14 is 5730 years.

9. How do fossils form?
Most fossils are laid down in sedimentary rock -(particles carried by streams and rivers that eventually settle to the bottom in layers)
Many fossils in the
Grand Canyon

10. The oldest particles, and therefore the oldest fossils will be at the bottom, with new layers being added.
The deeper down you go, the simpler the life forms are.
This leads some to believe that life began as simple prokaryotic cells and gradually became more complex because…

11. Older, simpler fossils at the bottom

12. What is the “fossil record”
Over the years, paleontologists (scientists that study fossils) have collected millions of fossils. This groups of fossils is called the Fossil Record
The fossil record represents the preserved collective history of the the Earth’s organisms.

13. The fossil record shows that some organisms that once lived are now extinct
triceratops
stegosaurous
archeopterous

14. The fossil record can show that organisms changed gradually over time
Fossil record of the whale
60 million
years ago
Today

15. Fossil record of the modern horse
Today
55 million
years ago

16. Fossil record of the camel
Today
40 million
years ago

17. Comparative Anatomy & Vestigial Structures
Evidence of Evolution
Comparative Anatomy
&
Vestigial Structures

18. A. Comparative Anatomy: The limbs of all of these organisms are similar in structure even though their function may be different

19. As vertebrates evolved, particular sets of bones were sometimes put to different uses…This may indicate a common ancestry

20. Some animals appear to have structures that no longer serve a function – (called vestigial structures)
Vestigial leg bones in a python

21. Vestigial wings in a flightless bird
Ex a penguin and an ostrich

22. Human appendix is vestigial
The human appendix has no function in
humans but is very
important in horses
and other animals

23. Human tailbone is a vestigial vertebrate tail
consists of fused
vertebrae that no
longer function
as a tail

24. Embryological Development
Evidence of Evolution
Embryological Development

25. Similarities in Early Development

26. Similar development must mean similar genes at work
Similar genes indicated common ancestry.
Differences in development are caused by genes that have mutated during the course of evolution.

27. Biochemical Evidence of Evolution
Hemoglobin in the blood

28. The more similar two organisms are, the more similar their DNA is.
This would indicate that they animals evolved from a common ancestor.