1. The Unifying Theme of Biology
Evolution
The Unifying Theme of Biology

2. True or False? Evolution says that man came from monkeys.
Scientists do not agree on the theory of evolution.
There is much evidence to support the idea of evolution by natural selection.
Charles Darwin was the first scientist to describe the idea of evolution.
Evolution is the idea that the organisms on Earth today have descended from ancestors and gradually changed during that process.

3. What is Evolution?
A process by which modern organisms have descended from ancient organisms
Change in the frequency of certain genes in a population over time

4. What is the Evidence For Evolution?
The Fossil Record
Evidence from Living Organisms

5. What is the Fossil Record?
A collection of fossils that represents the preserved collective history of Earth’s organisms

6. Examples of Fossils Whole preserved animals or plants
Skeletons or fragments of bone
Footprints
Eggs

7. Do all Living Things form Fossils?NO
Fossil formation requires specific conditions which are not common
Extremely cold temperatures
Hot, dry climate
Quantities of sap
Sedimentary rock
This means that the Fossil Record is incomplete like a puzzle with pieces missing

8. What Does the Fossil Record Tell Us?
The Earth is very old and changed slowly over time by natural forces like:
Weathering
Floods
Volcanoes
Shifting land

9. There have been major changes in Earth’s climate and geography over time
Fossils of tropical plants have been found in Antarctica
Fossils of shark teeth have been found in Arizona

10. Species have become extinct

11. Species alive today are similar to those that lived in the past

12. Questions Define the word “evolve”.
List two general areas that have provided evidence for evolution.
Fossils are only bones? Explain why this statement is true or false.
Why have scientists been unable to find all the fossils they need to demonstrate the evolution of organisms?
Have the species alive today always existed? Explain.

13. What is the Evidence from Living Organisms that Supports Evolution?
Similarities is Embryo Development
Similarities in Body Structures
Similarities in Chemical Compounds

14. How are Embryos Similar?
Due to a shared genetic blueprint (DNA)
Hox cluster-in vertebrates it controls the pattern of organ and structures from head to tail
(differences are due to helpful mutations)

15. What are Some Similarities in Body Structures Among Organisms?
Homologous Structures- develop from the same body parts but meet different needs (homo=same)

16. Vestigial Organs- structures that are no longer needed and may decrease in size
Snakes-tiny remnants of leg bones
Humans-appendix

17. Which Chemicals are Shared Among Organisms?
Nucleic Acids
DNA
RNA
ATP

18. Questions
How do the embryos of vertebrates compare at the earliest stages of development?
How does the presence of homologous structures support the theory of evolution?
Name some chemicals that all living things share.

19. How Does Evolution Occur?
“Nothing in Biology makes sense except in the light of evolution.”
Theodor Dobzhansky
biologist

20. What were Some Early Explanations for Evolutionary Change?
Jean Baptiste de Lamarck ( )
Desire to change- living things have an inborn urge to become more fit for their environment
Use and Disuse- organisms can alter their shape by using their bodies in new ways
Passing on Acquired Traits- characteristics obtained during a lifetime are passed on to offspring

21. What is the Current Theory of Evolutionary Change?
Charles Darwin
Evolution by Natural Selection

22. Living Things Overproduce
More offspring are created that can survive

23. Offspring Vary in their Traits
No two offspring are exactly alike
due to gametes having different sets of genes
mutations

24. There is a Struggle for Existence
Against each other
Mates
Food
Shelter
Habitat

25. Survival of the Fittest
The best adapted offspring survive and pass their genes (traits) on to their offspring

26. Questions
How did the artificial selection carried out by farmers help Darwin develop his theory of natural selection?
What are the four points of Darwin’s Theory of Natural Selection.
Compare the ideas of Darwin and Lamarck regarding evolution. Were Lamarck’s ideas truly scientific? Why or why not?
What did Darwin mean by “fitness”?

27. How Do New Species Develop?
Isolation-members of a population are separated and can no longer interbreed
Natural Selection will work differently on each group because they are now in different environments
Different adaptations may develop and the gene pools will differ

28. What are Some Processes of Genetic Change?
Natural Selection
Adaptive Radiation
Convergent Evolution

29. Natural Selection
The genes (and the traits they control) that are best suited will be passed on and those that are not suited will die out

30. Adaptive Radiation
A number of different species form from a common ancestor
Radiate-move away from the center
Adapt-evolve traits best suited for the new environment

31. Convergent Evolution
Different species evolve features with similar functions but different origins and structures (analogous structures)
Wings-butterfly vs bird
Eye-dog vs fly

32. Questions
Why is the concept of isolation important for natural selection?
Explain how new species are formed by adaptive radiation.
What are analogous organs? Give some examples. What type of evolution results in the formation of analogous organs?