1. Standard 9: Chapter 13 Biology 1 2015
Theory of Evolution
Standard 9: Chapter 13
Biology 1
2015

2. Objectives Proficient:
Explain how natural selection could affect a specific population.
Given a specific example of evidence, describe how it supports the theory of evolution.
Advanced:
Using the evidence discussed in class, apply it to a given population and predict how the population could change in the future.

3. Little bit of background:
Charles Darwin
Born:
February 12, 1809
(Who else was born on this exact date?)
Traveled the world Galapagos Islands
Interested in the natural world
Collected Evidence
Died: 1882

4. Theory of Evolution
Video Clip: What is a Theory?

5. Other pieces that are important to understand:
What is a species?
Group of organisms that are closely related and
naturally mate to produce fertile offspring
What is a population?
A group of organisms of the same species that live
in a specific area and interbreed.
Now remember, it is populations
that can evolve over generations of time
…(and not individual species suddenly adapting to the environment. No, no. Get that out of your head.)

6. Important to know the GTS: (Geological Time Scale)

7. Another view of the GTS:

9. How does evolution work?
Evolution is driven by the mechanism called Natural Selection.
Ever hear of the phrase: Survival of the Fittest?
Natural Selection: the process by which members of a population that have favorable variations and are better suited to their environment, survive and reproduce more successfully than less well adapted individuals do
(meaning those individuals
didn’t inherit traits that
would help them survive)

10. How does evolution work?
In order to understand natural selection, it is important to consider the following:
Time (By the way, do you know how old the earth is?)
Genetic Variation in populations
Overproduction of Offspring
Struggle for existence(Changes in environment/competition/finding mates/etc)
Differential Survival and Reproduction (adaptations and speciation)

11. Time
The earth is 4.6 billion years old. That’s a looooonnnnggggg time. In that time, environments (geological landscapes, climates, biological resources) have changed. Depending upon those changes, species have either
A.become extinct.
B.have been able to survive without change.
C.new species have derived from populations changing.
Evolution = change over TIME.

12. Genetic Variation
In the unit on Heredity, you learned that species inherit traits from previous generations. Those traits are varied because of sexually reproducing organisms. This allows those populations to be genetically diverse!

13. Overproduction of Offspring
Organisms produce more offspring than the environment can support. This is done to ensure that at least some of the offspring will reach adulthood so they can reproduce.
In these sea turtle
hatchlings, only 1 in 1000,
will survive to adulthood.

14. Struggle for Existence
Organisms in populations need to be fit, for those populations to continue to survive.
Fitness refers to individuals that have advantageous variations are more likely to survive and reproduce.
Ways in which to be fit:
-camoflauge
-bright colors (avoiding predators/attracting mates)
-faster/taller/stronger/smaller/etc.—depends on environment
(Basically, does the organism possess qualities that allow it to successfully survive? If so, you could say it is fit.)

15. Differential Survival and Reproduction
In any given environment, organisms struggle to survive in order to do what they instinctively need to do: reproduce. So, having inherited more favorable traits in order to survive has allowed populations to become adapted to the environment.
Adaptation: inherited trait that is more favorable for an organism to survive in an environment (anatomically, physiologically, or behaviorally)

16. How does Evolution really work?
Video Clip: How does Evolution Really Work?

17. Formation of New Species
Speciation:
-Species are considered “new” when their organisms can not interbreed successfully due to natural selection
The following are more contributing factors from natural selection to form a new species (speciation):
Environments change, therefore changing:
mating seasons
Organisms of populations become geographically isolated
Mutations

18. Discussion Questions
1.What is the name of the mechanism that drives evolution?
2. What does it mean?
3. What is fitness?
4. What is an adaptation?

19. How do we know evolution happens?
Evidence for evolution:
Fossils
Comparative anatomy
Embryology
DNA (proteins/amino acid/chromosome number similarities)

20. Evidence of Evolution Fossil Record- creates a geological time scale
Fossil- trace or remains of an organism that lived long ago. (Ex:impressions in rock/bones/organism preserved in tree sap=amber)
to find a complete fossil of an organism is very rare (organisms need to be buried rapidly)
paleontologists analyze sediments around fossil and arrange them from oldest to youngest to create fossil record
-Radioactive dating

21. Evidence of Evolution Anatomy and Development
comparing anatomy between different types of organisms can reveal similarities in body structures.
sometimes bones are present in reduced size or proportion and have no use or less important function than in other related organisms
ex. Appendix in humans
Vestigial structures- structures considered to be evidence of an organism’s evolutionary past
Ex. Hind limbs in whales

22. Evidence of Evolution
Homologous structures- structures that can be found in common ancestors of organisms
This shows that all organisms share evolutionary ancestry.

23. Evidence of Evolution: Comparative Embryology
Understanding that the development of embryos is similar among the different species of vertebrates. This also shows that species share evolutionary ancestry.

24. Evidence of Evolution: Similarities in DNA
Some species share very similar amounts of chromosome numbers, protein and amino acid combinations, and DNA sequences.

25. More examples of Natural Selection
tuberculosis- antibiotic strands evolved
Darwin’s finches- beak size changed
with food resources

26. copyright cmassengale

27. How do we know Evolution happens?
Video Clip: How do we know evolution happens?

28. Evolutionary Relationships
Cladogram- diagram that represents shared traits among species to show evolutionary relationships among species

29. Rate of Evolution
gradualism- model of evolution in which gradual change over a long period of time leads to new species

30. Rate of Evolution
punctuated equilibrium- model of evolution in which periods of rapid change in species is followed by periods of little or no change
Caused by a major or dramatic environmental change
(evolution in spurts)

31. Discussion Questions
1. What is speciation? 2. What are some pieces of evidence for evolution? 3. What are two example of comparative anatomy?

32. Vocabulary Practice
Wooooooo HOOOOOOOO

33. Vocabulary
Adaptation-

34. Vocabulary
Adaptation- inherited traits that allow a population to be more fit for an environment.
(Remember, individual species do not adapt themselves.)

35. Vocabulary
Fitness-

36. Vocabulary
Fitness- the ability to survive in an environment (because an organism has inherited more favorable traits in its DNA)
(how well you survive in your environment)

37. Vocabulary
Natural Selection-

38. Vocabulary
Natural Selection- the process by which organisms with traits well suited to their environment, survive and then are more likely to reproduce. THEREFORE, they pass down those more favorable traits. Overtime, the population of that particular species changes.
(Those favorable traits that are inherited are the adaptations!)

39. Vocabulary
Fossil-

40. Vocabulary Fossil- preserved remains of an ancient species/organism
Examples:
-bones
-impressions in soil or rock
-hardened tree sap that has collected organisms
-organisms frozen in ice or frozen ground

41. Vocabulary
Vestigial Structure-

42. Vocabulary
Vestigial Structure- the part of an organism that serves no useful function but shows evolutionary ancestry
Examples:
Human appendix
Pelvic and femur bones in whales

43. Vocabulary
Homologous Structures-

44. Vocabulary
Homologous Structures- similar structures in anatomy of different species that shows common ancestry

45. For who do we give credit to our understanding of natural selection?

46. For who do we give credit to our understanding of natural selection?
Mrs. Rakers! Haha j/k

47. For who do we give credit to our understanding of natural selection?
Charles Darwin