1. Evolution for Beginners
Only a theory?

2. Basic premises for this discussion
Evolution is not a belief system. It is a scientific concept. It has no role in defining religion or religious beliefs
Evolution is a theory…but you don’t get any better than that in science
There is a lot of contention about evolution, but not among scientists or scientific organizations.

3. Some basic definitions
Fact: an observation that has been repeatedly confirmed
Law: a descriptive generalization about how the physical world behaves
Hypothesis: a testable statement that can be used to build inferences and explanations

4. Some basic definitions
Theory: a well-substantiated explanation that incorporates facts, laws, inferences and tested hypotheses.
In science, you don’t get any better than a theory.

5. What is evolution? Let’s start by seeing what evolution is not.

6. What is evolution? A basic definition of evolution…
“…evolution can be precisely defined as any change in the frequency of alleles within a gene pool from one generation to the next."
- Helena Curtis and N. Sue Barnes, Biology, 5th ed Worth Publishers, p.974

7. So what does the definition mean?
Evolution is a change in the number of times specific genes that code for specific characteristics occur within an interbreeding population
Individuals don’t evolve, populations do
There is no implied “improvement” in evolution

8. So what does the definition mean?
Things don’t change because organisms want or need them to (Lamarkism)
There is no difference between macroevolution and microevolution. Macroevolution is merely a collection of microevolution events.

9. Definition problems
Part of the problem is that a number of different definitions for evolution can be found both within and without the scientific community. These can easily confuse laypeople.

10. Definition problems
"evolution: ...the development of a species, organism, or organ from its original or primitive state to its present or specialized state; phylogeny or ontogeny"
- Webster's
"evolution: The gradual process by which the present diversity of plant and animal life arose from the earliest and most primitive organisms, which is believed to have been continuing for the past 3000 million years."
-Oxford Concise Science Dictionary
"evolution: ...the doctrine according to which higher forms of life have gradually arisen out of lower."
- Chambers

11. Definition problems
In addition to being simply wrong, these definitions can cause confusion since it is common for non-scientists to enter into a discussion about evolution with such definitions in mind.

12. A brief history of evolution
Charles Darwin was born on February 12, 1809 in Shrewsbury, England.
From 1831 to 1836 Darwin served as naturalist aboard the H.M.S. Beagle on a British science expedition around the world.
He observed much variation in related or similar species of plants and animals that were geographically isolated from each other.
These observations were the basis for his ideas.

14. A brief history of evolution
Contrary to popular belief, Darwin was not the first person to describe the concept of evolution, but he was the one who gave it its driving force.

15. —Charles Darwin from "The Origin of Species“, 1859
Darwin presumed that populations of individuals changed over time, and, in 1844, he developed the concept of the driving force for evolution. It wasn’t until many years later that he published his idea.
“I have called this principle, by which each slight variation, if useful, is preserved, by the term Natural Selection.”
—Charles Darwin from "The Origin of Species“, 1859

16. Natural Selection
Darwin knew nothing of genes, but what he did have were two observations and a little inference that provided the motive force for evolution.

17. Natural Selection
Observation 1: Organisms generally have more offspring than can survive to adulthood.
Observation 2: Offspring are not identical. There is variation in their appearance, size, and other characteristics.

18. Natural Selection Survival of the “fittest.”
Inference: Those organisms that are better adapted to their environment have a greater likelihood of surviving to adulthood and passing these characteristics on to their offspring.
Survival of the “fittest.”

19. Darwin’s dilemma
Darwin was hesitant to publish his theories because of the backlash that previous authors received.
If this book is true, “religion is a lie, human law a mass of folly and a base injustice; morality is moonshine.”
-Adam Sedgwick’s response to Robert Chamber’s 1844 book, Vestiges of the Natural History of Creation, in which Chamber’s hinted that organic creation was the result of natural laws, not God’s intervention.

20. Darwin’s dilemma
It was a letter Darwin received on June 18, 1858, that precipitated the publishing of The Origin of Species.
Alfred Russell Wallace, exploring in Asia, had come to the same conclusion as Darwin.

21. Darwin’s dilemma
Darwin, with a strong sense of honor, arranged for a simultaneous reading of his and Wallace’s papers before the Linnean Society.
The readings were met with silence, so Darwin published the full text of his ideas.
…then it hit the fan.

22. -Bishop Samuel Wilberforce to Darwin defender, Thomas Huxley
“…tell me, is it on your grandfather’s or grandmother’s side that you are descended from an ape.”
-Bishop Samuel Wilberforce to Darwin defender, Thomas Huxley
“If…the question is put to me would I rather have a miserable ape for a grandfather or a man highly endowed by nature and possessed of great means and influence and yet who employs these faculties and that influence for the mere purpose of introducing ridicule into a grave scientific discussion I unhesitatingly affirm my preference for the ape.”
-Huxley’s response

23. In Darwin’s lifetime he would be recognized as one of the great masters of science. By the 1870s almost all serious scientists in England had accepted evolution.

24. Observation and Inference
Let’s do a little exercise…

25. Dinosaur tracks are common occurrences in the southern and eastern U.S.
Here is a section of tracks that were recently uncovered. Can you answer the following questions?

26. What is the size and nature of the organisms?
Were the tracks made at the same time?
How many animals were involved?
Can you reconstruct the events that occurred?

27. In what direction did the animals move?
Did they change speed or direction?
Was the soil moist or dry?
In what type of rock were the prints made?

28. The following summer some more digging revealed more of the track
The following summer some more digging revealed more of the track. What additional information have you gained that allows you to refine your answers?

29. Were the tracks made at the same time? How many animals were involved?
Can you reconstruct the events that occurred?
In what direction did the animals move?
Did they change speed or direction?

30. In the final summer of the excavation one last part of the footprint trail was uncovered. Does this section provide additional information to refine your hypothesis?

31. So what happened?
What part of your hypothesis is observation? What part is inference? What part is conjecture?

32. This is how science is done.

33. Ten questions about teaching evolution in the classroom
Teaching evolution in the K-12 classroom can pose pitfalls for a teacher. What follows are responses to 10 very common questions about evolution and its place in education.

34. 4. Why is evolution considered a scientific “fact?”
A scientific fact may be defined as a theory that has been repeatedly confirmed and never refuted.
Evolution fits this description, but that does not mean that new evidence couldn’t refine or disprove the theory. Science is a progression, not a destination.

35. 9. Does the evidence really exist?
In short, overwhelmingly. Numerous examples of discovery of predicted intermediate forms, genetic similarity studies, and new molecular mapping have only confirmed the theory
There are no cases where evolution has been found to be false

36. A copy of this presentation is available for download at:
Thank you for your interest, attention, and input.
Carl Wozniak,

37. Ch Evolution
The History of Life

38. Unit 4 – Evolution (Ch. 14, 15, 16)
Define Evolution
List the major events that led to Charles Darwin’s development of his theory of Evolution by means of Natural Selection
Summarize the major events of the Geologic Time Scale
Compare and contrast early experiments that support the concept of biogenesis and disproved spontaneous generation
List some examples of direct and indirect evidences of evolution
List the 6 different types of fossils & the technique used to identify the age of them.
Explain what the first cells were thought to be and give characteristics of them
Summarize the effects of the different types of Natural Selection on gene pools
Relate changes in genetic equilibrium to mechanisms of speciation
Explain the role of natural selection in convergent and divergent evolution
Analyze the Endosymbiotic Theory - including why the  Mitochondria and Chloroplasts were thought to be on their own.
Compare and contrast modern theories of the origin of life
Explain how the structural and physiological adaptations of organisms relate to natural selection
Identify adaptations of primates
Distinguish the evolutionary relationships of primates
Summarize the major anatomical changes in hominids during human evolution
List the phylogeny of the human species from Australopithecus to Homo sapiens.
Identify what probable explanation allowed humans to get to North America

39. SWBAT Scale
4: Same as a 3.0 but I can make inferences & application to the SWBAT’s
3: I COMPLETELY understand all parts of the SWBAT
2: I understand MOST of the SWBAT’s with teacher help
1: I understand a little of the SWBAT’s but need teacher help
0: I do NOT understand any part of the SWBAT’s and need help!

40. History of Life The record of life Early history of earth
High temps, active volcanoes,
Atmosphere consisted of carbon dioxide, methane, nitrogen, ammonia water vapor; very little free O2
Some scientists propose that organisms formed 3.9 billion years ago

41. History of Life The History of Rocks
Fossil – evidence of life found in rocks, 10,000 year minimum
Paleontologists – scientists who study ancient life
Most fossils are found in what type of rock?
Sedimentary
Fossils reveal evidence of environment that existed when the organisms lived

42. History of Life The age of the fossil
Relative dating – if rock & fossil lay has not been disturbed, the surface must be younger than deeper layers.

43. History of Life Radiometric Dating
Measures the age of rocks by measuring the decay of a radioactive isotope
Half-life – rate of decay
C-14 takes 5,730 years for its ½ life
Dating technique frequently produces inconsistent dates because the initial amt. of isotope can never be known for sure.

44. History of Life Fossils types Mold – Depression left (no organism)
Cast – minerals fill in space – replica of organism
Petrified – mineral replace hard parts – fine detail
Imprints – thin objects leave delicate patterns
Amber/Frozen – actual material in ice or sap
Trace fossils – footprints, wormholes
Evidence of an organism

46. History of Life Trip through time
Geologic time scale divided into 4 eras
Precambrain – life begins
Paleozoic – enormous increase in diversity
Mesozoic – changes in organisms
Cenozoic – where we are now
Mass extinction – entire groups of organisms disappear from fossil record almost at once

47. Geologic Time Scale

48. 1. Precambrian Era 0. 5bya to 4. 6 bya
1. Precambrian Era 0.5bya to 4.6 bya “Age of Bacteria” Earth’s first living organisms appear 3.5 bya What type of organism were these?
Prokaryotes
No life anywhere, no oxygen in the air

49. Precambrian Era 4 BYA – Water covers almost the entire Earth
2.2 BYA Stromatolites and Blue-Green Algae begin to fill the air with oxygen
What cellular process allowed the algae to fill the air with oxygen?
Photosynthesis
2.5BYA – The first continents form

50. Precambrian Era
1.4 BYA the first organisms with an enclosed nucleus and membrane-bound organelles appear.
These organisms are known as?
Eukaryotes

51. The Paleozoic Era 543-248 mya “Age of Invertebrates, Fish, & Amphibians”
Geological Events
380MYA – Oxygen levels reach about 20% (where they are today)
MYA- Abundance of sea life is what turns into the oil we use for cars today
575 MYA - Appalachian mountains formed
Colorado was covered in oceans

52. The Paleozoic Era 543-248 mya Life Events 500 MYA – First fish
400MYA – First insects
360 MYA – First Amphibians
350 MYA – First Trees form
300 MYA – First Reptiles.
Life moves out of the oceans

53. Paleozoic Era The End of an Era 248 mya fossil records show that:
95% of all marine species died off
75% of all land vertebrates died off
Evidence shows that this was the result of a large amount of volcanic eruptions causing CLIMATE CHANGE
This marked the end of the Paleozoic era and the beginning of the Mesozoic Era
What do you think happened to life on Earth after this point?

54. 3. Mesozoic Era 248mya -65mya “The Age of Reptiles”
Geological Events
200 MYA - Pangaea begins to break up
65 MYA - The Rocky Mountains begin to form heavily
Ferns and Gymnosperms are dominant Plant Life

55. The Mesozoic Era
Began approximately 245 million years ago after a major mass extinction.
Is subdivided into 3 periods:
Triassic
Jurassic
Cretaceous
Ends about 66 million years ago with a major mass extinction

56. Key theme: Pangea breaks up
Process will take 150 my and will extend into the Cenozoic
Laurentia/Baltica and Australia/Antarctica are still joined at the end of the Mesozoic

57. The Triassic Period 245 - 206 million years ago
Immediately after the Permian Mass Extinction
Lots of new area is open for animals to live

58. The Jurassic Period 206 - 144 Million Years Ago
Giant plant-eating dinosaurs
Vicious carnivore dinosaurs
Oceans full of fish, squid, sharks, etc.
Ichthyosaurs and Plesiosaurs
Pterosaurs
Birds

59. The Cretaceous Period 144 - 66 million years ago
Ends with a mass extinction around 66 million years ago
Approximately 60% of all species went extinct.
Affected many land animals/plants
Affected fewer marine animals
First flowering plants!

60. 4. Cenozoic Era 65mya - Present “The Age of Mammals”
Geological Events
Continents continue to move apart
1.6 MYA major ice age
Life Events
Mammals become dominate species on Earth
Flowering plants (angiosperms) become dominate plants on Earth

61. Cenozoic Era 35MYA – Early Primates 2.8 MYA – Homo habilis
500,000 years ago - First Homo sapiens

62. History of Life Earth began around 4.6 billion years ago
Life appears ~ billion years ago
Plate tectonics
Earth contains several rigid plates that drift on top of molten rock

63. History of Life Origins of life Early Ideas
Spontaneous Generation – the idea that non-living material can produce life

64. History of Life
Francesco Redi – Disproved spontaneous generation of large organisms
Fly's on meat
Louis Pasteur – disproved spontaneous generation of small (micro) organisms
Biogenesis - Idea that living organisms come only from other living organisms

65. History of life Origins Many theories
Can never be proven
One theory – simple organic molecules formed, then become organized into complex organic molecules; nucleic acids, proteins, and carbs.
Tested by Miller & Urey

66. History of Life Formation of the Protocell Evolution of cells
Large, ordered structure enclosed by a membrane that carries out some of life’s activities (growth and division)
Evolution of cells
Proposed characteristics of original cell
Anaerobic – No Oxygen needed
Heterotrophs – Cannot make their own food
Prokaryote – No nuclei
Archeabacteria
Live in harsh environments

67. History of Life Cells Eventually used up food supply.
Needed to start making their own food
Photosynthesis (autotrophs)
Photosynthetic Autotrophs
Produce O2, which helps produce O3
Endosymbiotic Theory
Eukaryotes evolved from symbiotic relationships between prokaryotes
Bacteria with Chloroplasts & Mitochondria

68. History of Life Endosymbiotic theory –click to watch animation
Video: How we think complex cells evolved - Adam Jacobson

69. Unit 4 – Evolution (Ch. 14, 15, 16)
Define Evolution
List the major events that led to Charles Darwin’s development of his theory of Evolution by means of Natural Selection
Summarize the major events of the Geologic Time Scale
Compare and contrast early experiments that support the concept of biogenesis and disproved spontaneous generation
List some examples of direct and indirect evidences of evolution
List the 6 different types of fossils & the technique used to identify the age of them.
Explain what the first cells were thought to be and give characteristics of them
Summarize the effects of the different types of Natural Selection on gene pools
Relate changes in genetic equilibrium to mechanisms of speciation
Explain the role of natural selection in convergent and divergent evolution
Analyze the Endosymbiotic Theory - including why the  Mitochondria and Chloroplasts were thought to be on their own.
Compare and contrast modern theories of the origin of life
Explain how the structural and physiological adaptations of organisms relate to natural selection
Identify adaptations of primates
Distinguish the evolutionary relationships of primates
Summarize the major anatomical changes in hominids during human evolution
List the phylogeny of the human species from Australopithecus to Homo sapiens.
Identify what probable explanation allowed humans to get to North America

70. SWBAT Scale
4: Same as a 3.0 but I can make inferences & application to the SWBAT’s
3: I COMPLETELY understand all parts of the SWBAT
2: I understand MOST of the SWBAT’s with teacher help
1: I understand a little of the SWBAT’s but need teacher help
0: I do NOT understand any part of the SWBAT’s and need help!