1. Evolution

2. Evolution
Evolution explains how variations in species have occurred over time
Life on earth began more than 3 billion years ago
The first living organisms were simple, single celled organisms that were most likely heterotrophs. Autotrophs came later.

3. Evolution Continued
Over time, more complex single-celled creatures developed.
Then, about a billion years ago, increasingly complex, multicellular organisms began to appear.

4. Life’s Natural History is a record of Successions & Extinctions
mya
Quaternary
Tertiary
Cretaceous
Jurassic
Triassic
Permian
Carboniferous
Devonian
Silurian
Ordovician
Cambrian
Ediacaran
Precambrian,
Proterozoic,
&
Archarozoic
1.5
Plants
Birds 63
Mammals
135
Reptiles
Seed Plants
Flowering
Amphibians
Insects
180
Dinosaurs
Teleost Fish
Land Plants
225
Jawless Fish
Molluscs
Arthropods
Chordates
Multicellular Animals
280
Green Algae
Photosynthetic Bacteria
350
Anaerobic Bacteria
400
430
500
570
700
4500
Life’s Natural History is a record of Successions & Extinctions

5. Life has changed & changed the Earth
Living creatures have changed Earth’s environment, making other life possible

6. The Theory of Evolution
The theory of evolution is accepted as the central theme of modern biology. Its helps biologists understand how the variations among individuals can lead to changes in an entire species of organisms.

7. So much evidence has been collected by thousands of scientists that evolution is now a theory, which is a concept that has been tested and confirmed in many different ways and can be used by scientists to make predictions about the world.

8. LaMarck Lamarke's Theory of Acquired Characteristics
Lamarke thought that you would gain or lose features if you overused or didn't use them, and you could pass these new traits onto your offspring.
Lamarck noted how well-adapted organisms were to their environments, and believed that fossils could be understood as less perfect forms which had perished in the struggle for increasing perfection. He explained adaptation as a result of change caused by environmental pressures.

9. This was known as the Inheritance of Acquired Characteristics.
Example: A giraffe stretched its neck to reach higher leaves, and this stretched neck would be a trait inherited by its offspring
Lamarke's Theory was eventually proven to be FALSE!
Features gained during life are NOT passed on to children.

10. Darwin's Theory of Evolution by Natural Selection.

11. “On the Origin of Species by Means of Natural Selection”
Voyage:
November 24, 1859, Darwin published
“On the Origin of Species by Means of Natural Selection”

12. Darwin was a naturalist who observed many species
Darwin was a naturalist who observed many species. He is famous for his trips to the Galapagos Islands, his observations of the finches (and other animals) and his theory of Natural Selection or Survival of the Fittest.
1. Variation exists among individuals in a species.
2. Individuals of species will compete for resources (food and space)

13. 3. Some competition would lead to the death of some individuals while others would survive
4. Individuals that had advantageous variations are more likely to survive and reproduce.

14. Darwin’s finches Warbler finch Woodpecker finch Small insectivorous
tree finch
Large
insectivorous
Vegetarian
Cactus finch
Sharp-beaked finch
Small ground
finch
Medium
ground finch
Large ground
Insect eaters
Bud eater
Seed eaters
Cactus
eater
Warbler
Tree finches
Ground finches

15. This process he describes came to be known as Natural Selection
The favorable variations are called adaptations
 These variations could be passed on if the trait occurred in the sex cells

16. Evidence of Evolution Fossil Evidence
Fossil record---creates a geologic time scale. Shows us that today’s organisms descended from ancestral species
The fossil record is layers of sedimentary rock containing fossils

17. New layers cover older ones, creating a record over time
Fossils within layers show that a variety of organisms have populated Earth throughout a long period of time

18. Fossil Record

19. Comparative embryology
Embryos of different species develop almost identically
Indicate presence of a common ancestors

20. Comparative embryology
Shows how structures that are embryologically similar, but have different functions.

21. Homologous Structures
Structures that are similar between different organisms.

22. Vestigial Organs--seemingly functionless parts, snakes have tiny pelvic and limb bones, humans have a tail bone.
some snakes & whales show remains of the pelvis & leg bones of walking ancestors
eyes on blind cave fish
human tail bone

23. Hind leg bones on whale fossils

24. Biochemistry and DNA
Comparing DNA & protein structure. The closer the sequence of bases and amino acids the more closely related the organisms are
every organism has a universal genetic code consisting of DNA and RNA

25. Comparative hemoglobin structure
Human
Macaque
Dog
Bird
Frog
Lamprey 8 32 45 67
125 10 20 30 40 50 60 70 80 90
100
110
120
Number of amino acid differences between
hemoglobin (146 aa) of vertebrate species and that of humans

26. Which branching tree diagram best represents the information above ?

27. Which statement is a valid conclusion that can be drawn from the diagram on the left?
(1) Snails appeared on Earth before corals.
(2) Sponges were the last new species to appear on Earth.
(3) Earthworms and sea stars have a common ancestor.
(4) Insects are more complex than mammals.

28. Which statement is a valid inference based on
the information in the diagram on the left?
(1) Species A is the common ancestor of all life
on Earth.
(2) Species D is more closely related to species E
than to species F.
(3) Species B is the ancestor of species F.
(4) Species C is the ancestor of species that exist
at the present time.

29. Which statement is supported by the diagram on the left?
(1) Species C is the ancestor of species B.
(2) Species D and E evolved from species B.
(3) Species X evolved later than species D but
before species B.
(4) Both species C and species D are related tspecies X.