1. Intro to Evolution – Ch 15
Objective: 3.05 Examine the development of the theory of evolution by natural selection including: development of the theory; the origin and history of life; 1

2. The Fossil Record Chapter 15.1
Objective: Examine the development of the theory of evolution by natural selection including: fossil and biochemical evidence; mechanisms of evolution; applications (pesticide and antibiotic resistance) 2

3. Why use fossils?
Scientists have used the fossil record to construct a history of life on Earth.
Earth’s life forms appeared 3.5 billion years ago
Fossil record is not complete, but pretty good for general information 3

4. Fossils Trace of long-dead organism
Formed in sediment – dust, sand, mud – by wind or water
Hard body parts frozen in time
Minerals replace soft tissue > rocks 4

5. Types of fossils Mold – imprint of organism
Cast – imprint replaced with minerals – looks like a model
Evidence of behavior – footprints/tracks
Insects petrified and frozen in amber 5

6. Dating Fossils Relative Dating Radiometric Dating
Rock layers are put down in order
Oldest on bottom, youngest layers on top
Radiometric Dating
Use Carbon-14 for ages 50,000 years or less
Half-life is 5730 years 6

7. Nicolaus Steno
Law of superposition – successive layers of rock or soil were deposited on top of one another by wind or water
Stratum (lowest layer) – or layer in cross section is the oldest, top layer is youngest 7

8. Earth’s age ~ 4.6 billion years
Relative age – age by comparison
e.g. I am older than you by comparison yet you don’t know my exact age
E.g. the cement in the foundation of the building is older than the roof by comparison yet I don’t know the exact age in years of the building
Absolute age – age in years by radiometric dating (carbon -14) 8

9. Succession of forms Extinct – disappeared from existence
Mass extinctions – large numbers of species disappeared
– drastic environmental change like volcanic activity, collisions with asteroids 9

10. First organisms begin with prokaryotes in Precambrian era (540 mya)
Biogeography – study of the geographical distribution of fossils
Indicates that organisms arise in areas where similar body forms lived suggesting that they are the new-improved model! A modified version 10

11. Theories of Evolution Chapter 15.2
Objective: 3.05 Examine the development of the theory of evolution by natural selection including: development of the theory; the origin and history of life; 11

12. Processes of science vs. processes of faith
Observe  Ask questions  Propose hypotheses  Conduct Investigation  Alter hypotheses
Faith:
Religious faith is a belief; Faith is not altered to fit evidence
I ask students to learn theory of evolution – they don’t have to “believe” in it just understand it.
I will not teach creationism nor intelligent design – they are not science 12

13. Evolutionary Timeline13

14. Jean Baptiste de LaMarck
inheritance of acquired traits – characteristic passed to offspring; not determined by genes
repeated use or disuse of body part during their lifetime was then passed down to offspring or inherited
E.g. webbed feet of duck
Related fossils to living organisms based on similar appearance
1st to say organisms change over time 14

15. Use & Disuse - Organisms Could Change The Size Or Shape Of Organs By Using Them Or Not Using Them
Blacksmiths & Their Sons (muscular arms)
Giraffe’s Necks Longer from stretching)

17. Inheritance Of Acquired Traits Traits Acquired During Ones Lifetime Would Be Passed To Offspring
Clipped ears of dogs could be passed to offspring!

18. Charles Darwin & Alfred Wallace
Independently propose that species were modified by natural selection – when organisms with traits well suited to the environment reproduce more successfully than other organisms
Published Origin of the Species
Sailed on HMS Beagle to Galapagos Islands, west of S. America 18

19. What is the Theory of Evolution by Natural Selection?
Populations would grow exponentially if there were unlimited resources
Environmental factors limit reproductive capacity
Organisms compete for resources
There is variation within populations and those with useful adaptations survive
The survivors reproduce and pass on their genes
The new generation will have a greater frequency of the adaptive traits
Over a long period of time, the differences are so great that the result could be a new species 19

20. HMS Beagle voyage Naturalist
Read Principles of Geology by Charles Lyell
Uniformitarianism – geological cycles observed today are the same processes from long ago
e.g. volcanoes erupt the same today as millions of years ago 20

21. Darwin sailed on the Beagle for 5 years making observations as the ship’s naturalist.

22. 22

23. He studied: tortoises, finches & more
Island species varied from mainland species AND from island-to-island species
Each island had long or short neck tortoises 23

24. 24

25. Finches: Finches on the islands resembled mainland finch
More types of finches appeared on the islands where the available food was different (seeds, nuts, berries, insects…)
Finches had different types of beaks adapted to their type of food gathering 25

26. 26

28. Evolved from a common remote ancestor
phylogenetic tree - shows evolutionary relationships
Phylogenetic Tree or Ancestral Tree showing proposed evolution

29. Darwin’s 2 theories: Descent with modification
Newer organisms in fossil record are modified descendants of older species
All species descended from original type of life
Modification by natural selection
Organisms with favorable traits have more offspring than others without them– adaptive advantage
Can adapt to environment therefore more fit 29

30. Survival of the Fittest
Fitness
Ability of an Individual To Survive & Reproduce
Adaptation
Inherited Characteristic That Increases an Organisms Chance for Survival

31. Survival of the Fittest
Adaptations Can Be:
Physical
Speed, Camouflage, Claws, Quills, etc.
Behavioral
Solitary, Herds, Packs, Activity, etc.

32. Survival of the Fittest
Fitness Is Central To The Process Of Evolution
Individuals With Low Fitness
Die
Produce Few Offspring
Survival of the Fittest AKA Natural Selection

33. Survival of the Fittest
Key Concept
Over Time, Natural Selection Results In Changes In The Inherited Characteristics Of A Population. These Changes Increase A Species Fitness In Its Environment

34. Descent With Modification
Takes Place Over Long Periods of Time
Natural Selection Can Be Observed As Changes In
Body Structures
Ecological Niches
Habitats

35. Descent With Modification
Species Today Look Different From Their Ancestors
Each Living Species Has
Descended
With Changes
From Other Species
Over Time

36. Descent With Modification

37. EVIDENCE for EVOLUTION
Evidence from fossils.
The Geographical Distribution of Living Species
Homologous Structures of Living Organisms
Similarities In Early Development 37

38. Homologous Body Structures
Structures That Have Different Mature Forms But Develop From The Same Embryonic Tissues

39. Homologous Body Structures
Scientists Noticed Animals With Backbones (Vertebrates) Had Similar Bone Structure
May Differ In Form or Function
Limb Bones Develop In Similar Patterns
Arms, Wings, Legs, Flippers

41. Homologous Body Structures
Not All Serve Important Functions
Vestigial Organs
Appendix In Man
Legs On Skinks

42. Similarities In Early Development
Embryonic Structures Of Different Species Show Significant Similarities
Embryo – early stages of vertebrate development

43. Similarities In Embryonic Development

44. Evidence from genetics.
All organisms share the same basic mechanism of heredity (DNA/RNA)
E.g.: mtDNA evidence for human evolution
A branching tree radiating from a common ancestor – phylogenetic tree
We can conduct research on other species to understand our own genes. 44

45. Similarities in DNA Sequence

46. Evolution in action.
Many bacterial pathogens (origin of feeling – what started the disease) have evolved resistance
to antibiotics
In the case of HIV, which causes AIDS, significant
viral evolution occurs within the course of infection of a single patient 46

47. Evolution of drug-resistance in HIV

48. Many agricultural pests have evolved resistance to chemicals that farmers have used for only a few decades.
Moreover, scientists can perform experiments to study evolution in real time using bacteria and fruit flies that reproduce quickly.

49. Evolution
of pesticide
resistance
in response
to selection