1. Evolution by Natural Selection
Part 1: Darwin
Part 2: Adaptations
Adaptation Song Youtube

2. Who is Charles Darwin?
Part 1

3. An English naturalist in the 1800’s
Studied to be a minister
Did most of his research while working on the HMS Beagle as the science officer
Voyage took 5 years
Sailed along the coast of South America
Explored the Galapagos Island chain
famous for studying the finches
Collected thousands of specimens (plants and animals), collected data on weather and ocean currents

4. How did tortoises and birds differ among the islands of the Galapagos?
Each island had its own type of tortoises and birds that were clearly different from other islands

5. Darwin’s finches – helped define theory.
 Each bird species evolved from a common finch from the mainland (C. America).
All have different beaks depending on feeding behavior

6. Phylogeny of the Galapagos Finches

7. Darwin’s Theory of Evolution

8. Implications
Another way of saying this is that there is very little gene flow between the islands and the mainland.
Genetic mutations occurred, including beak shape and neck length, which in turn allowed for varied diets. 8 8

9. Charles Darwin’s Theory Theory of Evolution by Natural Selection Theory- well-tested explanation that unifies a broad range of observations. Evolution- change in an organism over time; modern organisms descended from ancient organisms

10. Charles Darwin’s Ideas
Biological evolution is change in species over time.
This was not a new idea at the time
But there were no good mechanisms to explain how these changes occurred
Natural selection is the mechanism behind evolution, and this is what Darwin contributed. 10 10

11. Darwin’s Theory of Natural Selection
 Origin of the Species – book written for both scientists and non-scientists. Created biggest debate of science vs religion ever…
 Survival of the Fittest – theory that only the strongest survive to reproduce and therefore are better adapted to the environment. Basis for theory of evolution.

12. Proposed The Theory of Evolution By Natural Selection
Based on 5 key observations
organisms best adapted to the environment will most likely survive; “survival of the fittest”
organisms that survive will mostly likely reproduce
genetic traits are passed on from parents to offspring who usually look similar to parents
more offspring are produced than can survive – the idea of overproduction to ensure some will survive to reproduce
organisms compete for needed resources:
a. food
b. water
c. shelter
d. space / territory
e. mates 

13. Artificial selection

14. Selective Breeding Selective Breeding Humans and Dogs
Dogs originated from the Grey Wolf
Breeding for physical traits
Many breeds of dogs - all one species
Human induced and not natural selection

16. Descent with Modification
Each living species has descended with changes from other species over time
How have humans changed?

17. Natural Selection and Species Fitness
Overtime, natural selection results in changes in the inherited characteristics of a population.
These changes increase a species fitness (survival rate)
Natural selection does not result in perfection
Better adapted to the current circumstances

18. Darwin’s Theory of Evolution
Selective Breeding- humans choose specific organisms for breeding because they have useful traits from the natural variation within a species, hoping to pass on so these traits accummulate in offspring
Struggle for existence- competition among members of a species for food, living space, and the other necessities of life.
Fitness- ability of an organism to survive and reproduce in its environment.
Survival of the fittest- individuals that are best suited for their environment survive and reproduce most successfully.
Descent with Modifications- principal that each living species has descended, with changes, from other species over time.

19. Evidence of Evolution Fossil Record Homologous Body structures
Vestigial Structures
Similarities in Embryology
Geographic Distribution of Living Species

20. Relative vs. Absolute Dating

21. Carbon-14 Dating

22. Evidence of Evolution Homologous Body Structures
Turtle
Homologous Body Structures
A body part that is structurally similar in 2 or more species
e.g. Wing of bat, human arm, leg of turtle
Alligator
Bird

23. Homologous Body Structures

24. Vestigial Organs traces of homologous organs in other species
Organ that serves no useful function
e.g. Appendix
Cormorants of Galapagos

25. Evidence of Evolution Similarities in Embryology
In their early stages of development, chickens, turtles, rats etc. look similar

26. Embryological development

27. The development of pesticide resistance in insects is another example of real-time evolutionary change.
Natural selection is also responsible for:
• antibiotic resistance in
bacteria
• herbicide resistance of
weeds
• HIV resistance to anti-
retroviral drugs

28. What are Adaptations?
Part 2

29. Types of Adaptations

30. 1.) wings, beak shapes, long legs, webbed feet antlers, etc.
structural:
a body part or coloration that aids survival
1.) wings, beak shapes, long legs, webbed feet antlers, etc.
2.) camouflage or protective coloration
* allows an organism to blend in or hide in its surroundings
3.) mimicry or protective resemblance
* organism looks like or acts like something it’s not

31. 1.) hibernation (slows down metabolism, breathing, heart rate)
Physiological
the ability to control life functions to aid survival
1.) hibernation (slows down metabolism, breathing, heart rate)
2.) marine mammals holding breath for long time
3.) certain plants in extreme conditions (salty, dry, underwater)

32. 1.) behaviors taught to or learned by experience
Behavioral:
actions that aid survival
learned behaviors
1.) behaviors taught to or learned by experience
2.) example: knowing where the water hole is or knowing what to eat
Instincts
1.) behaviors genetically inherited from parents; “just know how”
2.) example: knowing when to migrate, sensing danger, mating season

33. Traits that help an organism survive
Helpful, positive physical or behavioral characteristics
Allow organisms to:
1. get food/water
2. protect themselves
3. reproduce/find a mate
4. withstand environment