1. Natural Selection & Evolution

2. TSW investigate and understand how populations change through time, including:
How variation of traits, reproductive strategies, and environmental pressures impact on the survival of populations
Recognizing how adaptations lead to natural selection
How new species emerge

3. Charles Darwin On the Origin of Species Sailed with the HMS Beagle
Observations made in the Galapogos Islands
These observations helped him form the theory of how species change over time called natural selection

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Voyage of the Beagle
During his travels, Darwin made numerous observations and collected evidence that led him to propose a hypothesis about the way life changes over time.
That hypothesis has become the theory of evolution (aka theory of natural selection).
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5. Living Organisms and Fossils
Darwin collected the preserved remains of ancient organisms, called fossils.
Some of those fossils resembled organisms that were still alive.
Others looked completely unlike any creature he had ever seen.
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Darwin's Observations
The Galápagos Islands
Darwin observed that the Galápagos Islands were close together but had very different climates.
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The Journey Home
Darwin observed that the characteristics of many animals and plants varied noticeably among the different islands of the Galápagos.
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The Journey Home
Darwin wondered if animals living on different islands had once been members of the same species.
These separate species would have evolved from an original South American ancestor species.
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9. Natural selection vs Evolution?
Fact: Evolution- process by which modern organisms have descended from ancient organisms.
Theory- Natural Selection- based on the principles of genetics.
*Note-A scientific theory is a well-supported testable explanation of phenomena that have occurred in the natural world. 9

10. Evidence for Evolution
Fossil record
Anatomy
Homologous structures
Analagous structures
Vestigial structures
Embryology
Molecular biology (DNA differences)

11. What is a Population?
Populations are groups of interbreeding individuals that live in the same place at the same time
Individuals in a population compete for resources with each other.
Populations evolve over many generations, individuals don’t.

12. How Does Evolution Work?
Populations produce more offspring than the environment can support
The unequal ability of individuals to survive and reproduce leads to the gradual change in a population over many generations.

13. Mechanism for change in a population of organisms.
Animals who have greater fitness survive in environment and live to reproduce
Random changes (mutations) can lead to greater or less fitness
Adaptations allow an organism to survive better in their environment

14. Physical Behavioral What is an Adaptation?
Evolutionary process by which an animal becomes better suited for its environment.
Physical
Behavioral

15. Physical Adaptations
are body structures that allow an animal to find and consume food, defend itself, and to reproduce its species.
toad

16. Camouflage (use of color in a surrounding)
Physical adaptation
Camouflage (use of color in a surrounding)
The chameleon can change its color to match its surroundings. Can you do that?

17. (looking or sounding like another living organism)
Physical adaptation
Mimicry
(looking or sounding like another living organism)
The Viceroy butterfly uses mimicry to look like the Monarch butterfly. Can you tell them apart?
I’m the Viceroy!
Not poisonous
Poisonous
I’m the Monarch!

18. Chemical defenses (like venom, ink, sprays)
Physical adaptation
Chemical defenses (like venom, ink, sprays)

19. Physical adaptations
Body coverings & parts (claws, beaks, feet, armor plates, skulls, teeth)
The elephant’s trunk is a physical adaptation that helps it to clean itself, eat, drink, and to pick things up.

20. Behavioral Adaptations…
Behavioral Adaptations allow animals to respond to life needs. They are the animals’ actions.

21. Behavioral Adaptations
Learned
These behaviors must be taught.
Instinctive
These behaviors happen naturally & don’t have to be learned.
Methods of gathering & storing food
Defending oneself
Hibernating
Finding shelter
Raising young

22. Adaptations Can arise in response to environmental pressures
Temperature
Antibiotic resistance in bacteria
Pesticide resistance
Morphological changes in peppered moths

23. Darwin Video
Show Darwin Video
Answer Questions:
Who is Darwin?
What college did he attend? What did he study?
What book did most people read that explained creation?
How many years was he on the Beagle? How old was he?
What was the name of his book?
What was his Mechanism of change called?