2. Everything must evolve…

5. Charles Darwin Father of Evolution Proposed a way how evolution works
How did creatures change over time?
by natural selection
Collected a lot of evidence to support his ideas
British naturalist
What did Darwin say?
What evidence supports Evolution by Natural Selection?
What impact did Evolution have on biology?

6. Voyage of the HMS Beagle
Invited to travel around the world
After graduation Darwin was recommended to be the conversation companion to Captain Robert FitzRoy, preparing the survey ship Beagle for a voyage around the world.
FitzRoy chose Darwin because of his education, his similar social class, and similar age as the captain.
Darwin noted that the plants and animals of South America were very distinct from those of Europe

7. Voyage of the HMS Beagle
Stopped in Galapagos Islands
500 miles off coast of Ecuador
The origin of the fauna of the Galapagos, 900 km west of the South American coast, especially puzzled Darwin.
On further study after his voyage, Darwin noted that while most of the animal species on the Galapagos lived nowhere else, they resembled species living on the South American mainland.
It seemed that the islands had been colonized by plants and animals from the mainland that had then diversified on the different islands

8. Darwin found… many unique species
Many of Darwin’s observations made him wonder… Why?
Darwin asked:
Why were these creatures found only on the Galapagos Islands?

9. Darwin found… clues in the fossils
present day Armadillos
Darwin found:
Evidence that creatures have changed over time
ancient Armadillo
Darwin asked:
Why should extinct armadillos & modern armadillos be found on same continent?

10. Darwin found: Different shells on tortoises on different islands
Darwin asked:
Is there a relationship between the environment & what an animal looks like?

11. The finches clinched it for Darwin

12. Darwin concluded: Evolution Darwin called this…
Each species has descended, with changes, from other species over time.
Darwin called this…
Descent with modifications or
Evolution
(change in population over time)

13. Data supports Evolutionary Theory

14. Darwin’s Theory of Evolution by Natural Selection
Species have changed through time and are related by descent from a common ancestor
The primary mechanism of Evolutionary Change is Natural Selection

15. Fossil Record - the history of life recorded by remains from the past
Fossil Record - the history of life recorded by remains from the past. Most fossils are at least 10,000 years old.
Body Fossils
Trace Fossils

16. What is found?
- Fossils exist and fossil forms are unlike species living today
1. Fossil Sequence?
When fossils are arranged according to
their age, they show successive
evolutionary change
2. Fossil Intermediates?
Transitional fossils have been found between:
Amphibians & reptiles, reptiles & birds,
reptiles & mammals, apes and humans

17. The Evolution of Horses
A particularly well-documented case of evolution within a group

18. The Fossil Record is Incomplete
At the time of Darwin, the fossil record was VERY scanty. A great deal of progress has been made since, but it is far from finished.
The fossil record is relatively incomplete for several reasons:
1. Soft tissues are rarely preserved
2. Movement of the earth's crust has obliterated and/or covered many fossils
3. Fossilization takes place only in certain types of habitats and favorable environments
4. Paleontologists have not dug up every place on earth

19. Even if there were no fossil record, the evidence from living organisms would be more than sufficient to demonstrate the historical reality of evolution

20. Vestigial Structures Features that have no apparent function
Typically have an important function in related species
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display
Vestigial structures
Ex: Hindlimb joints in whales and snakes

21. Vestigial Structures in Humans
Tailbone
Wisdom Teeth
Appendix

22. Evidence for the relatedness of life forms?
Hypothesis: all living organisms have descended from a common ancestor
Prediction: we should also be able to see evidence of relatedness of species
-Homology
-Geographic distribution

23. Homology
Homology: a similarity between species that is the result from the inheritance of traits from a common ancestor
The features of every creature reflect history as well as adaptation
3 types of homologies
- structural
- developmental
- genetic

24. Analogous Structures Different structures, same function
Suggests that organisms do not share a close common ancestor
Ex. Hawk, butterfly, & bat can all fly but have different wing structure

25. Homologous Structures
Same structure in different animals
Suggests that organisms share common ancestor
Ex. Forelimbs of human, cat, whale, & bat
Same bone structures

26. Homology vs. Analogy
Natural selection appears to have favored similar adaptations
in unrelated organisms in similar environments-->
these structures are analogous
Whereas homologous structures
share structural similarity, but not function, analogous structures share function but not structural similarity since they evolved independently

27. Embryos show evolutionary history
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display
Embryos show evolutionary history
Homologous structures in adults develop from homologous groups
of cells in embryos --> they share developmental pathways

28. Comparative Embryology
Analyzing embryos with similar structures to show common ancestor

29. Dog Fetus
Human fetus

30. Bat Fetus

31. Genetic Homologies All living organisms share the same genetic code
Chromosome and gene similarities between
species match evolutionary similarities
This is true for both coding regions and
“junk DNA”

32. Molecules reflect evolutionary divergence

33. Geographic Distributions
Species that are extremely similar to one another tend to be
clustered geographically (Ex.: Darwin’s finches)
Living species are more similar to fossil species in the same area
than they are to living species in other areas
The law of succession
general correspondence between fossil and living forms in same geographical area
Darwin used this observation to predict that fossils
of ancient humans should be found in Africa

34. That Evolution Has Occurred Is A Fact

35. Fossil Record -
Evidence of Evolution

36. How to estimate how old: 1) the deeper the layer that the fossil is found in, the older it is 2) the fossils near the surface are younger and more complex
Which rock layer is the oldest?
Which fossil is older: a fossil in layer 4 or a fossil in layer 2?
What observations did you make about the organisms in layers 1-3 and 4-5? What does this tell you about the type of environment? 5 4 3 2 1

37. How is this evidence for evolution?
Although scientists have a found a lot of fossils (and still continue to find them!), they still have missing pieces in the fossil records of species.
The camel however, has a nearly complete fossil record of it’s evolution
How is this evidence for evolution?
What is evolution? Change over time. Fossils give you an idea of what this changed looked like, of how the change the occurred.

38. Change by Chance Activity
Procedures:
1. You will need a pencil for this activity. You will be working with a group of students and drawing a picture. You cannot look at anyone else’s drawing.
2. The drawing should be face down until the signal to begin is given.
3. I will signal the beginning and end of each 15-second interval.
4. I will give the first student in each line 15 seconds to draw, not trace, the image on the colored paper onto their blank paper.
5. The first student will then pass their drawing to the next person. The second student in each row 15 seconds to draw, not trace, the first student’s drawing on his or her own paper.
At the end of the 15 seconds, the second students pass their drawings to the third students, and so on until all students in a group have had a chance to draw the reptile.
7. Have each group label all of their drawings with a group name, mix the order, and place them together.
I will collect each group’s drawings and redistribute each set to a different group. In groups, sequence the order of the drawings and then tape them on the wall.
Choose one person from the original group confirm the accuracy of the sequencing.

39. Why was sequencing the drawings difficult?
How was this experience similar to sequencing fossil records?
How was this experience different from sequencing fossil records?

40. Turn to an elbow partner and answer the question below
Turn to an elbow partner and answer the question below. Discuss how to determine the correct answer.
Instructional strategy – Follow the directions in the slide. (Ans: B)

41. With the same elbow partner describe the changes in the fossils you see in each layer and what they tell you about that time period.
Instructional strategy – Allow 1-2 minutes for students to discuss (changes are in the layers).

42. Turn to a different partner
Turn to a different partner. Compare layer C to layer F in the diagram below. What evidence do these fossils provide of changes on earth?
Instructional strategy – With a different partner, allow students to discuss. (Area was once aquatic, but now is not.)

43. Living or once living things share common ancestors and fossils provide evidence for common ancestry.
Instructional strategy – Present information in the slide and compare the fossils in the pictures for similarities. Have students copy the statement into their notes.

44. Changes in fossil records…. What do they mean?

45. Stasis -
Punctuated equilibrium is a evolutionary theory which proposes that once species appear in the fossil record they will become stable, showing little net evolutionary change.
In this picture, the color of the moths changes very little.

46. Gradualism - suggest that organisms evolve through a process of slow and constant change.
For instance, an organism that shows a fossil record of gradually increased size in small steps, or an organism that shows a gradual loss of a structure.
In the case of the moths above, they gradually change color over time.

47. Physical characteristics of organisms change over time and fossils provide evidence of change.
Instructional strategy – Have students copy the statement to the left. Go over the diagram to the right, noting the similarities and the changes from toes to hooves and in tooth structure.

48. Summarizing Strategy: 3 – 2 – 1
Describe three ways in which scientists support the theory of evolution.
Identify two ways in which scientists know the physical characteristics of organisms change over time.
Describe why the fossil record is important.
Instructional strategy – present information on the slide, and have students complete individually. May be used as a basis for grouping for differentiation.