1. Why do so many different animals have the same structures, the arm bones in a human are the same bones as a flipper in a whale?

2. Why are there bones and fossil evidence of creatures that no longer exist? What happened to these creatures?

3. Why do organisms have structures they no longer use, like the appendix in a human? Non functioning wings in penguins?

4. Evolution

5. These questions and others can be answered by EVOLUTION
The Theory of Evolution is considered a Unifying Theory of Biology, because it answers many of these questions and offers and explanation for the data.

6. Charles Darwin born in Shrewsbury, England, in 1809
studied medicine at Edinburgh University ( ) where the sight of blood and surgery without anesthetics repulsed him
studied to become a clergyman at Cambridge University ( )

7. He sailed aboard the Beagle for 5 years, working as a naturalist.
After Cambridge, Charles was recommended for a surveying trip on the HMS Beagle.
He sailed aboard the Beagle for 5 years, working as a naturalist.

8. Darwin noticed that everywhere he went on his voyage, the animals and plants differed vastly.
Patterns in the species suggested that the species had changed over time and had given rise to new and different species.

9. Many of Darwin’s conclusions were based on observations of wildlife in the Galapagos Islands.
The Galapagos Islands lie 500 miles west of Ecuador in the Pacific Ocean, directly on the equator.
“Galapagos” means turtle.

10. Darwin noticed on these islands, there were several types of finches.
Galapagos finches
Darwin noticed on these islands, there were several types of finches.
What it must have been like to be Darwin…

11. Galapagos finches
In particular, Darwin observed something odd about the finches: they all looked like a bird he had seen on the South American continent.

12. Darwin wondered if the birds and other animals had been created to match their environment, why didn’t these birds look like the birds of the African continent, since the environments of both the Galapagos and Africa were similar.

13. Once on the islands, the birds must have changed over the years.
Darwin guessed that some of the birds from South America migrated to the Galapagos.
Once on the islands, the birds must have changed over the years.

14. This would explain the numerous species of birds present.
large ground finch
woodpecker finch
cactus finch
This would explain the numerous species of birds present.

15. evolution Darwin called this… descent with modification or
(change in species over time)

16. Darwin extended these principles to biology, which helped him form his theory of…
Natural Selection
…or Survival of the Fittest.

17. Five basic components of
Natural Selection

18. 1. All species have genetic variation.
Every species is different, even within itself.
Look around you…are you all the same?

19. 2. The environment presents challenges to survival.
There is a constant struggle for survival. Examples are:
Drought
Fires
Floods
Snowstorms
Hurricanes
Tornadoes
Other natural disasters

20. 3. Organisms produce more offspring than can survive
3. Organisms produce more offspring than can survive. Competition (struggle for existence) exists WITHIN and AMONG species.
Within a Species
Among a Species
food
food
space
space
mates

21. Organisms who possess favorable traits will leave more offspring.
4. Survival of the fittest. Some organisms are more suited to their environment as a result of variation in the species.
Fitness: the ability of an individual to survive and reproduce in its specific environment.
Fitness is a result of adaptation
Organisms who possess favorable traits will leave more offspring.
In other words, he who spreads the most genes wins!
1st

22. 5. Decent with modification
5. Decent with modification. Living species today are descended with modifications from common ancestral species.
Characteristics of fit individuals increase in a population over time.
Over time, genes for less favored characteristics will be eliminated from the gene pool.
Example: giraffes and their long necks.

23. Natural Selection: Survival of the Fittest
An adaptation is any inherited characteristic ( a genetic variation ) that can increase an organism’s chance of survival.
An organism does not change because of need or desire to survive. The organism either already has the variation that enables it to survive or it dies

24. Adaptations Adaptations are evidence of evolution
Structural adaptations
Mimicry – enables 1 species to look like another
Yellow jacket wasp
Harmless syrphid fly

25. Adaptations
Camouflage enables organisms to blend in with their environment

26. Evidences of Evolution
Today most evidences for evolution are grouped into five main categories:
Fossil Record
Biochemical
Comparative Anatomy
Biogeography
Observable Events

27. COMPARATIVE ANATOMY HOMOLOGOUS STRUCTURES
structures with similar structure but different function
(ex: turtle, alligator, bird, mammal)
Turtle
Alligator
Bird
Mammal

28. COMPARATIVE ANATOMY Homologous structures show Similar genes
Descent from a common ancestor
Turtle
Alligator
Bird
Mammal
Ancient lobe-finned fish

29. COMPARATIVE ANATOMY VESTIGIAL STRUCTURES
organs so reduced in size that they are nonfunctioning remnants of similar organs in other species
ex: human tailbone, appendix, whale pelvis
Whale pelvis diagram by cbray

30. COMPARATIVE ANATOMY ANALOGOUS STRUCTURES
Body parts that do not have common evolutionary origins but are similar in function

31. COMPARATIVE ANATOMY EMBRYOLOGY
Embryos of different species may appear similar in early stages of development
Embryo drawings by cbray
ex: vertebrate development

32. COMPARATIVE ANATOMY Comparison of similarities in embryos can show:
Relationship to a common ancestor
Embryo drawings by cbray

33. FOSSIL RECORD Paleontology
Fossil – remains or traces of an organism that lived long ago
Remains: ex. bone, tooth, or shell
Traces: ex. burrow, footprint, or imprint
Photos by cbray

34. FOSSIL RECORD Most fossils are found in layered sedimentary rock
Oldest fossils are on the lowest layer
Layers diagram by cbray

35. BIOCHEMICAL THE GENETIC CODE
Triplets of DNA nitrogen-base sequences that code for specific amino acids
The amino acid triplet is the same in almost all organisms.
Genetic code table by cbray