1. Welcome Back! Drosophila activity is due in class tomorrow.
The sections on GULO and Hemoglobin genes are extra credit.
Pick up Applications of Evolution handout, it’s due Friday.
Test Friday on Evolution. Primarily:
Natural Selection
Lines of Evidence to Determine Descent

2. Today Work time on Drosophila and Applications of Evolution homework.
I’m going to come around and check in with you as you work on your recall of Natural Selection.

3. DNA and Cladograms
The Drosophila activity is due tomorrow, including all questions.
The sections of the packet on GULO and Hemoglobin genes are optional, for extra credit.
Today: Read the article and answer the questions.
While you are doing this, come to me one-by-one. I’ll pose a natural selection situation to you, and you explain to me the answer. Worth 0-4 points (equal to one of those mini-quizzes) and I’ll give you feedback afterwards.
Remember: No misconceptions, mention the 4 inputs, change in allele frequencies

4. 1. Please turn in your Drosophila Packet. (No need to get it stamped)
Fossil Record
1. Please turn in your Drosophila Packet. (No need to get it stamped)
Reminder: Applications of Evolution due Friday. Test Friday (maaaaybe Monday for C block).

5. Recap Who can explain to me: What is a homologous structure?
If two organisms share a homologous structure, what does that say about they relation to each other?
What does that say about what their common ancestor looked like?
What is a vestigial organ?
What does a cladogram show?
What is extinction?

6. Objectives Have a general understanding of the timeline of life
Be able to use fossil evidence to determine ancestry

7. Fossils
What is a fossil?

8. (155 mya, 15 cm
wingspan)
Fossils
What is a fossil? A fossil is any trace or remains of an organism, preserved by natural processes.
Fossilized skeletons are the obvious example, but that’s not all that fossils are limited to.
Fossils include fossilized droppings, tracks, eggs, nests, tracks, body imprints, and even whole bodies preserved in ice, tar, or amber.
(Baby Psittacosaurus in their nest, killed in
Volcanic eruption 100+ mya)

9. Fossils
Preserved baby wooly mammoth, that’s its REAL body! Preserved in ice for a little over 10,000 years.
From such preserved bodies, we’ve sequenced all the mammoth’s mtDNA and most of its nuclear DNA. Scientists are also working on extracting viable gametes.
This, too, is a fossil even though it’s not a rock skeleton.

10. Fossils
Coprolites, or fossilized animal dung, indicate diet, behavior, infections, and more about the animal.
It also provides information about the ecosystem. Even if there’s no independent imprint of a plant, it can still be recorded in the droppings of local herbivores, for instance.
T-Rex coprolite 50 cm long:

11. Fossils
The oldest insect preserved in amber comes from 146 million years ago. Amber has also preserved bacteria, archaea, plants, and protists.

12. Fossils
Any organism can leave a fossil, though this process happens to some more easily than others.
Which of these individuals is most likely to leave fossil evidence?

13. Fossils
Creatures with hard parts are more likely to leave fossil evidence.
Scientists include these probabilities in their calculations.

14. Fossils There are nearly 100 different ways to date a fossil.
Carbon-14 dating, potassium-argon dating, uranium-lead dating, biostratigraphy…
Some methods are more chemistry-based, others are more exclusive to geologists
Scientists use many of them on each fossil to be confident of their results.

15. History of Life
We know from chemists, geologists, and physicists that the Earth formed 4.6 billion years ago. But how well can you all estimate when life on Earth underwent some major transitions?
We will use the floor as a timeline. Each floor tile = 250 million years, so the total timeline = 18.4 tiles.
I have some event slips for you, like “First Bacteria” and “First Earthworm.” I challenge you to work together to place them in order on the timeline, and to place them in roughly the right years.
The group that I judge to get the closest gets stickers.
Cut out the slips, note they’re not currently in order.

16. History of Life
The “Tree of Life” is vast, beginning 3.8 billion years ago and with more extinct species than living ones. Humans have only occupied a small fraction of it. Observe:
Earth is 4.6 billion years old.
The first thing that met all the characteristics of life developed 3.8 billion years ago.
The first multicellular organism developed 1 billion years ago.
The first animal developed 600 million years ago.
The first species in the genus Homo developed 2.5 million years ago.
The first Homo sapiens developed 200,000 years ago.

17. Using the Fossil Record
How can the fossil record be used with respect to evolutionary history?
The broad trend: Fossils show that the form and structure of organisms have changed over time.

18. Using the Fossil Record
How can the fossil record be used with respect to evolutionary history?
The broad trend: Fossils show that the form and structure of organisms have changed over time.

19. Using the Fossil Record
Fossils also provide information and the where and when.
Dating the fossil tells you the when.
The location of the fossil tells you about the range. (We’ll do a lab of this soon.)
Geologists love us evolutionary biologists, our fossils have the added benefit of giving them more data on tectonic plate shifts.

20. Using the Fossil Record
You find two fossils in the same layer of rock. One is a plant, the other an insect. From this, you can conclude:
A. The insect ate the plant
B. The insect laid its eggs on the plant.
C. They lived at the same time.
D. They lived at different times.

21. Using the Fossil Record
You find two fossils in the same layer of rock. One is a plant, the other an insect. From this, you can conclude:
C. They lived at the same time.
Your conclusions about their lives will depend on more than just finding them in the same layer.

22. Using the Fossil Record
Remember the refrain?
More _____ = More ______ = More ______ Last Common Ancestor

23. Using the Fossil Record
Remember the refrain?
More COMMON = More RELATED = More RECENT Last Common Ancestor
Fossils are used to determine ancestry by comparing them with living organisms and other fossils.
Fossils show homologous and vestigial structures just like living creatures do.
For example!…

24. This fossil is dated to 145 mya. What are your observations?

25. Do you notice any homologous structures that this species shares with birds?

26. Using the Fossil Record
Do you notice any homologous structures that this species shares with birds?
Feathers on wings, tail, body
Fused clavicles
Opposable big toe
Many more

27. Do you notice any homologous structures that this species shares with dinosaurs?

28. Using the Fossil Record
Do you notice any homologous structures that this species shares with dinosaurs?
Jaws with pointy teeth
Long bony tail
Three claws on each arm/wing
Killing claws on toes
Many more

29. Using the Fossil Record
This species is called Archaeopteryx. Which of the following are appropriate conclusions we can draw?
A. Archaeopteryx shares a common ancestor with birds.
B. Archaeopteryx shares a common ancestor with dinosaurs.
C. The common ancestor for Archaeopteryx and birds had feather-like structures.
D. The common ancestor for Archaeopteryx and dinosaurs had a bony tail.
E. Archaeopteryx is more closely related to birds than to humans.

30. Using the Fossil Record
All of the above.
Archaeopteryx is a classic “intermediate form,” a creature with features definitive to two groups.
It’s not a true bird, or a true dinosaur. It has recent common ancestry with both.

31. Problems
Five problems incoming. A sticker if you get all five correct.

32. Problems
1. Mammals, birds, and reptiles all have a eustachian tube connecting the ear canal to the pharynx.
A) How does this indicate common ancestry?
B) What does it tell you about the ear of their common ancestor?

33. Problems
2. Dorudan atrox, an extinct whale ancestor, has tiny vestigial hind limbs, as can be seen from its fossils.
Modern whales do too. From this, you can conclude:
A. Whales can travel on land when necessary.
B. Whales evolved from a four-legged animal.
C. Whales are turning into four-legged animals.
D. Whales have functional hind legs they don’t use so that they can better adapt to water.

34. Problems
3. These show the fossils of extinct horse ancestors, and the modern horse. Which statement is best supported by the data?
A. Horses changed over time.
B. The horse has been a carnivore.
C. The horse has few common ancestors.
D. The horse always lived in the same ecosystem.

35. Problems 4. What kind of structure is shown here?
5. These data best support this conclusion:
A. The size of these bones is the same.
B. These species share common ancestors.
C. These species developed at the same time and place.
D. The chemical makeup of these species is almost exactly the same.

36. Problems
1. Mammals, birds, and reptiles all have a eustachian tube connecting the ear canal to the pharynx.
A) How does this indicate common ancestry?
More similar = more related = more recent common ancestor. A homologous structure is one that’s derived from a common ancestor. Etc.
B) What does it tell you about the ear of their common ancestor?
Their common ancestor had a eustachian tube connecting its ear canal to its pharynx.

37. Problems
2. Dorudan atrox, an extinct whale ancestor, has tiny vestigial hind limbs, as can be seen from its fossils.
Modern whales do too. From this, you can conclude:
A. Whales can travel on land when necessary.
B. Whales evolved from a four-legged animal.
C. Whales are turning into four-legged animals.
D. Whales have functional hind legs they don’t use so that they can better adapt to water.

38. Problems
3. These show the fossils of extinct horse ancestors, and the modern horse. Which statement is best supported by the data?
A. Horses changed over time.
B. The horse has been a carnivore.
C. The horse has few common ancestors.
D. The horse always lived in the same ecosystem.

39. Problems 4. What kind of structure is shown here?
A homologous structure.
5. These data best support this conclusion:
A. The size of these bones is the same.
B. These species share common ancestors.
C. These species developed at the same time and place.
D. The chemical makeup of these species is almost exactly the same.

40. Essential Points About Fossil Formation
A fossil is a trace or remains of an organisms that’s been preserved by natural processes.
These can include fossilized bones, imprints, tracks, amber or ice-preserved bodies, etc.
Any organism can leave a fossil, though this happens more easily to some organisms than to others.
We have fossils of everything from bacteria to plants to many kinds of animals
There are more nearly a hundred different ways to date a fossil. Scientists use many of them on each fossil to be confident of their results.

41. Essential Points About Life History
The “Tree of Life” is vast, with more extinct species than living ones. Most of the Earth’s history has been lifeless, or has only featured unicellular life. Humans are a very recent arrival.

42. Essential Points About Fossil Data
Fossils show that the form and structure of organisms have changed over time.
They also provide information about where & when. Fossils found in the same layer of rock come from organisms that existed in the same time period. Deeper layers of rock come from further back in history.
Fossils are used to determine ancestry by comparing them with living organisms and other fossils.
Fossils show homologous and vestigial structures just like living creatures do.

43. Extinction! What is an extinction?
If species are all constantly evolving all the time according to the pressures of their current environments, why do extinctions happen?

44. Fossil Record
Turn in your Applications of Evolution article worksheet.
Test Monday.
Hominid Fossil Lab questions due Monday.
Today: finish maps for first part of period. We’ll do some review once everyone is done.

45. Objectives Be able to use fossil evidence to determine ancestry
Have a general understanding of human evolution.

46. Hominid Fossil Lab
To give you an example of how fossil evidence can be used to construct evolutionary hypotheses, we’ll map out the locations of human ancestor fossil finds. (These data are a couple years old, a few more fossils have been found since then but they all fit into the same ranges.)
Follow directions to make your map, then answer the questions to develop your hypothesis.
Finish the map in class at least. The questions are due the day of the exam.

47. Videos
How fossils form
History of life

49. Which of the following provides the most conclusive evidence that organisms of two different species share a common ancestor?
A. They live in the same ecosystem.
B. They reproduce at the same time.
C. They have similar DNA sequences.
D. They have similar body movements.

50. On island chains like the one shown, animal populations that spread from the main island to the other islands can evolve into separate species.
Which of the following best explains what favors speciation in this situation?
A. Predators on the main island can easily migrate to follow the populations to the other islands.
B. Lack of disease on the other islands enables the populations to grow and change without limit.
C. The physical separation of the islands is a barrier to gene flow between the populations.
D. The climatic conditions of the islands allow the populations to breed all year and produce several generations.

51. Frogs, lizards, and birds all have a similar arrangement of bones in their limbs. Which of the following does this similarity most likely indicate about these animals?
A. They move in the same way.
B. They have a common ancestry.
C. They evolved at the same time.
D. They are comparable in size as adults.

52. Some willow trees alter the chemical composition of their leaves when attacked by caterpillars. Compared to normal leaves, the chemically altered leaves are less nutritious and are more difficult for caterpillars to digest.
Which of the following is a likely effect of this ability to alter leaf composition?
A. Willow trees with this ability will attract more caterpillars than other willow trees.
B. Willow trees with this ability will have a survival advantage over other willow trees.
C. More butterflies will lay their eggs on willow trees with this ability than on other willow trees.
D. Caterpillars that feed on willow trees with this ability will be larger than caterpillars on other willow trees.

53. The drawings show some trilobite and crinoid fossils.
Which of the following is the most reasonable conclusion when fossils of these two different types of organisms are found in the same layers of rock?
A. Crinoids were prey of trilobites.
B. Crinoids were ancestors of trilobites.
C. Crinoids and trilobites had similar ancestors.
D. Crinoids and trilobites lived at the same time.

54. Some scientists use molecular evidence to study evolution
Some scientists use molecular evidence to study evolution. One type of molecular evidence is the amino acid sequence of particular proteins in various species.
Which of the following best describes what the study of these sequences reveals about the species?
A) The more similar sequences are, the faster the species will coevolve
B) The more similar the sequences are, the more closely related the species are
C) The longer the sequences are, the earlier the species evolved in geologic history
D) The longer the sequences are, the more adapted the species are to their environments

55. In 1861, a complete skeleton of an Archaeopteryx was discovered in limestone rocks that were 150 million years old. The fossils showed that this Archaeopteryx had a long bony tail, three claws on each wing, and a mouth full of teeth - which are all characteristics of dinosaurs - but it also had feathers on the long bony tail.
The fossil evidence supports an evolutionary link between which two animal groups?
A) Fishes and birds
B) Reptiles and birds
C) Mammals and reptiles
D) Amphibians and fishes

56. California king snakes may exhibit different patterns of stripes
California king snakes may exhibit different patterns of stripes. According to evolution by natural selection, which of the following is the most likely result if a snake-eating predator can more easily detect the snakes with the crosswise stripes?
A) The percentages of snakes born of each type will not change
B) Snakes with lengthwise stripes will become more common
C) Snakes with crosswise stripes will learn to move faster
D) A new type of king snake with no stripes will emerge

57. The graph above represents the range of birth weights for offspring in a mammal population.
As is typical in many mammal populations, offspring with an average weight at birth have a higher survival rate than offspring with a very low or very high birth weight. Based on this information, which of the following graphs is the best prediction of what will happen to the range of birth weights in this population over time?

58. The bone structures of a porpoise flipper and a bat wing are shown above.
Which of the following conclusions is best supported by the structure of each limb?
A) The porpoise and bat share a common ancestor.
B) The porpoise and bat limbs are adapted primarily for grasping.
C) The porpoise and bat evolved relatively recently in geologic history.
D) The porpoise and bat limbs are designed to support the entire weight of the animal.

59. On the Galápagos Islands, finches adapted over time to different food sources through changes in their beak structure.
Which of the following most likely resulted from the finches’ beak structure adaptations?
A. A decreased predation on finches.
B. An increased species diversity of finches.
C. An increased competition among finches.
D. A decreased reproductive rate in finches.

60. Dutch elm disease is a fungal infection of elm trees that usually results in death. The disease has killed millions of North American elm trees that were not resistant to the fungus. Scientists have bred resistant elms by crossing North American species with Asian species that show resistance.
Which of the following best describes how natural selection would promote resistant elm populations once the resistance genes from the Asian species were successfully introduced?
A. After encountering elms with resistance genes, fungi would avoid elms and begin to attack other tree species.
B. Resistance would spread to all of the mature elms in a population from the few trees that acquired resistance.
C. By reproducing with each other, elm trees with resistance genes would create super-resistant elms with twice the number of resistance genes.
D. Elm trees with resistance genes would survive and pass on resistance to offspring, while trees without resistance would more likely be killed by the fungus.

62. Evolution Exam
1. Turn in your Applications of Evolution article and Hominid Fossil Lab.
2. Last minute studying opportunity.
I especially recommend that you review the sample MCAS essay answers handout. That is what I expect from you on the essay section of this exam.
22 multiple choice, 2 essays (2-3 sections each). Write 1 thorough paragraph in response to each essay section (questions 25-27).
3. When you’re done, silently work on homework, study, or read. No iPods. Math and history books are available.