1. Copyright Pearson Prentice Hall
Biology
Copyright Pearson Prentice Hall

2. Copyright Pearson Prentice Hall
Evolution
Photo Credit: Art Wolfe Incorporated
Copyright Pearson Prentice Hall

3. Do now Collect papers at front . What does the term “Evolution” mean?
Use your definition of evolution to describe why the giraffe's neck is so long.

4. Evolution What does it mean? Change in a species over time
Process by which modern organisms have descended from ancient organisms

5. Review and complete the worksheet on major events in geologic time
With your partner, sort major events of evolution into chronological order.
Have students arrange the events in order. Tape them together and tape them on the board. As a whole class, review the events. Note when major extinctions occur and hypothesis why they may have occurred.

6. Evidence for Evolution
The Fossil Record
Homologous Body Structures
Similarities in DNA

7. Fossil record
The fossil record provides evidence for the history of life over geological time.

8. Copyright Pearson Prentice Hall
What are fossils?
Remains of dead organisms are buried by layers of sediment, which forms new rock.
The fossil record provides evidence about the history of life on Earth. Most fossils are formed in sedimentary rock.
Copyright Pearson Prentice Hall

9. How does the fossil record help us explain evolution?
Fossil record shows species have changed over time.
Fossil record shows how individual species changed. For example, the whale’s early ancestor was a four legged mammal but over time evolved and diversified into multiple species of whales.

10. How does the fossil record help us explain evolution?
Fossil record shows when species vanished and when species appeared over geological time
Explain that the KT boundary is when an massive asteroid slammed into earth. In rock layers beneath the boundary line, dinosaur fossils were abundant and in rock layers above the the KT boundary, dinosaur fossils are absent

11. Copyright Pearson Prentice Hall
Evolutioin
Has progressed from simple to complex organisms
Copyright Pearson Prentice Hall

12. Copyright Pearson Prentice Hall
DNA EVIDENCE
DNA Sequences among a variety of species have been compared
High degree of similarity between some species. What does that mean?
Remind students what DNA sequences look like
What does the chart tell us about which species is mostly closely related to humans? Does it mean chimps are our ancestor? No, but we may have a common ancestor.
Copyright Pearson Prentice Hall

13. Exit slip What happened to species as the environment changed?
How does the fossil record support the concept of evolution?

14. More Evidence for Evolution
Homologous Body Structures as Evidence for Evolution
Copyright Pearson Prentice Hall

15. Copyright Pearson Prentice Hall
Evidence of Evolution
Homologous Structures
Parts of the body that may look different but develop from the same set of cells are called homologous structures.
Copyright Pearson Prentice Hall

16. Copyright Pearson Prentice Hall
Evidence of Evolution
Homologous Structures
Turtle
Alligator
Bird
Mammal
The limbs of these four modern vertebrates are homologous structures. They provide evidence of a common ancestor whose bones may have resembled those of the ancient fish shown here. Notice that the same colors are used to show related structures. Homologous are one type of evidence for the evolution of living things.
Homologous Structures show that organisms evolved from a common ancestor
Homologous structures are one type of evidence for the evolution of living things.
Remind them that these changes occur over millions of years.
Ancient, lobe-
finned fish
Copyright Pearson Prentice Hall

17. Copyright Pearson Prentice Hall
Human, cat, whale, bat
Ask why would bones evolve such different functions in each of these animals?
Difference would begin with a mutation – change in base sequence.
Different environmental conditions may favor a mutation over “normal” base sequence
Copyright Pearson Prentice Hall

18. Copyright Pearson Prentice Hall
Evidence of Evolution
Vestigial structures: The body part is so reduced in size some species that they are remnants of homologous body parts in other species.
Whale descended from 4 legged terrestrial mammal; still has pelvis and femur but is no longer functional
Copyright Pearson Prentice Hall

19. Check Your Understanding
Complete the Homologous and Vestigial Organ sections of the packet provided.
Read directions carefully.
Use colored pencils to color structures appropriately.
Copyright Pearson Prentice Hall

20. Copyright Pearson Prentice Hall
Exit Slip
What could be a driving force that causes the changes in the limbs of the organisms discussed today?
Copyright Pearson Prentice Hall

21. Copyright Pearson Prentice Hall
Why Are We Different?
Why do some cats have short hair and some cats have long hair?
Different allele for the same trait (HH/Hh or hh)
HH/Hh = short hair
hh = long hair
Provide example of how you may have cats with both types of hair in a natural population. If climate changes causing the temperatures to decline, which cats are most likely to survive?
Copyright Pearson Prentice Hall

22. What causes traits to be different among individuals?
What caused different alleles to develop?
Mutation in the gene
Change in the nucleotide sequence (CAT – CAA)
How can a cat have no fur?
A mutation in the gene, producing a new allele!
Copyright Pearson Prentice Hall

23. Copyright Pearson Prentice Hall
Sources of Variation
Mutations
Crossing Over during Prophase of Meiosis I
Separation of Homologous Chromosomes during Anaphase of Meiosis I
Copyright Pearson Prentice Hall

24. Variation in the gene pool
The greater the variation in the gene pool, the more opportunities for evolution to occur.
What would happen to a small population with very little variation when faced with environmental change?
What would happen to a small population with great genetic variation when faced with environmental change?
What would happen to the frequency of an unfavorable allele?
Copyright Pearson Prentice Hall

25. What Drives Species To Change Over Time?
Lamarck 18th-19th century
Realized there was great variation in species
Fossil record showed that species changed over time
Provide an example from the classroom – this idea is similar to saying if “Joey” works out and builds his muscles, then he will pass on large muscles to his children.
This appears to be a very common misconception – students think that individuals can change (“adapt”) and that is an evolutionary event
Copyright Pearson Prentice Hall

26. What Drives Species To Change Over Time?
What is the mechanism for evolution?
Lamarck (1801) : one of the first scientists to propose a theory for evolution
Inheritance of Acquired Traits
As the giraffe reached for food,
his neck would get longer
This “Acquired Trait” would
be passed on to his offspring
But Does It Work?
Provide an example from the classroom – this idea is similar to saying if “Joey” works out and builds his muscles, then he will pass on large muscles to his children.
This appears to be a very common misconception – students think that individuals can change (“adapt”) and that is how species change over time
Copyright Pearson Prentice Hall

27. Selection As a Force of Evolution
Natural variation in population
Artificial selection to produce organisms with specific traits
Russian foxes were bred for less aggressive behavior
Copyright Pearson Prentice Hall

28. What Drives Natural Selection?
What drives the evolution of a species?
Natural variation in a population
Environmental change
Habitat loss
Climate change
Struggle for Existence
Limited resources/competition
Results in Natural Selection
Provide examples of environmental change
Warming climate, change in habitat
- We know that major environmental changes have wiped out many species; but some survived – why?
Copyright Pearson Prentice Hall

29. The Theory of Natural Selection
Must have variation in a population
Phenotypic variation
Some individuals must have different traits than others.
An environmental pressure that makes one form of a trait more favorable than others
Provide examples of environmental change
Warming climate, change in habitat
Provide example of variation -
Copyright Pearson Prentice Hall

30. Biological Adaptation
When species’ phenotype changes in response to environmental change, biological adaptation occurs.
Biological adaptation occurs within a population over a very long time.
Biological adaptation does not occur in an individual.
Genetic variation must be present for adaptation to occur.
Copyright Pearson Prentice Hall

31. Biological Adaptation
If you are cold, you get a sweater – however you have not adapted biologically to the cold, but you have adjusted your behavior.
Copyright Pearson Prentice Hall

32. Case Study: Horse Evolution
The ancestor to the modern horse was a small four legged animal living in the sheltered forests. As the environment warmed, the forests decreased, the horse was forced into a grassland environment. Given the lack of shelter from predators, the horse needed another way to escape from predators.
Order the cards provided to show the evolution of the leg and hoof of the horse.
Did the horse adapt to the environmental change or adjust to the environment?
Copyright Pearson Prentice Hall

33. Survival of the Fittest
Does the survival of the fittest mean organisms that the strongest or biggest will survive? If not, what determines “fitness”?
Fitness: organism’s ability to survive in a particular environment, successfully reproduce and pass on favorable traits to offspring.
Copyright Pearson Prentice Hall

34. Copyright Pearson Prentice Hall

35. Copyright Pearson Prentice Hall
15-3
The scientist who motivated Darwin to publish On the Origin of Species was
Alfred Russel Wallace.
Charles Lyell.
Jean-Baptiste Lamarck.
Thomas Malthus.
Copyright Pearson Prentice Hall

36. Copyright Pearson Prentice Hall
15-3
Differences among individuals of a single species are referred to as
artificial selection.
genetic variation.
survival of the fittest.
environmental adaptation.
Copyright Pearson Prentice Hall

37. Copyright Pearson Prentice Hall
15-3
Changes that increase a species' fitness in its environment over time are due to
the principle of common descent.
the geographic distribution of that species.
natural selection.
habitat selection.
Copyright Pearson Prentice Hall

38. Copyright Pearson Prentice Hall
15-3
An inherited characteristic that increases an organism's chance of survival is called a(an)
homologous structure.
vestigial organ.
adaptation.
analogous structure.
Copyright Pearson Prentice Hall

39. Copyright Pearson Prentice Hall
15-3
Evidence used by Darwin to support the idea of evolution included all the following EXCEPT
fossils that demonstrate change over time.
the genetic mechanism by which useful traits are inherited.
the geographic distribution of living things.
the presence of many homologous structures in plants and animals.
Copyright Pearson Prentice Hall

40. END OF SECTION