1. The Theory of Evolution

2. #1
What is a Theory?
A theory is the best explanation based on the evidence available.
There is a great deal of evidence to support the theory of evolution.

3. What is evolution? Definition: Result:
The process of change in a species over time
Result:
A species changes so much over time that the species is no longer the same as its original ancestor and would not be able to mate with the original ancestor.

4. What is the evidence that supports the theory of evolution?#2
What is the evidence that supports the theory of evolution?
Similar species (like the finches)
Fossils (very different organisms were alive millions of years ago)
Similar DNA (humans & chimps have 99.9% same DNA)
Analogous structures (similar bones in a hand, fin, and wing)

5. Species?
What is a species?
A species is a group of organisms that can mate and produce fertile offspring! #3

6. What does fertile mean?
Definition:
Can have offspring

7. How can one species become 2? (Evolution in Bacteria)
living on a rotting log
living under a rock
How can one species become 2?
(Evolution in Bacteria)
Separate Species

8. Common Ancestors
A common ancestor is a previous species that new species evolve from.
Evolutionary theory suggests that monkeys and humans have a common ancestor.
Misconception: Humans evolved from monkeys. THIS IS NOT TRUE!
WHAT IS TRUE? Humans and monkeys (and apes) have a common ancestor.

10. Common Ancestor:
6 million years ago
Evolutionary Tree

11. Why do scientists use a Tree vs. something else?#4
Why do scientists use a Tree vs. something else?
Where the branches meet the trunk shows a common ancestor!

12. What are some examples of organisms with a common ancestor?#5
What are some examples of organisms with a common ancestor?
Monkeys and humans
Land plants and seaweed

13. Evolution is NOT: #6 Evolution is NOT changes in population size
Evolution is NOT individual organisms growing and going through metamorphosis such as a tadpole changing into a frog
Evolution is NOT individual organisms evolving during their life time. THIS IS NOT POSSIBLE!
An organism cannot acquire (get) a better trait during its life and then pass it on to its offspring.

14. How Does Evolution Happen?
Mutations randomly occur to produce variations. Sexual reproduction also creates variations.
Organisms with beneficial variations (adaptations) are better able to survive.
Over time, a variety of beneficial mutations accumulates in the species.
The accumulation of many changes over time can lead to the production of a new species!

15. #7
Put the steps in order! 3
___Over time, a variety of beneficial mutations accumulates in the species.
___Mutations randomly occur to produce variations. Sexual reproduction also creates variations.
___The accumulation of many changes over time can lead to the production of a new species!
___Organisms with beneficial variations (adaptations) are better able to survive. 1 4 2

16. Evolution of the Horse How has the horse changed over time? #8
Different Species #8
How has the horse changed over time?
body shape
toes to hooves
size (bigger)

17. Misconceptions on How Evolution Occurs:
NOT TRUE: Organisms get the mutations they need and so they evolve to fit their environment.
NOT TRUE: 2 species (such as cat & dog) can mate to create a brand new species.

18. How Quickly Does Evolution Happen?#9
How Quickly Does Evolution Happen?
Time for evolution to happen depends on…
Reproduction (type, rate, gestation period, number of offspring, etc.)
Mutations: (more mutations = faster evolution)
(more pollutants can lead to more mutations)
Environmental changes (will reduce some variations, increase other variations)
Example: bacteria found in a hospital may evolve rapidly
(fast reproduction, changing environment due to various medicines, etc.)

21. Albert Einstein
9 years

22. Summarize… Organism Time Frame Numbers #10 Rate of evolution Bacteria
5 hours
3 million
Cats
9 years
(78,840 hours)
11 million
Humans 1
Rate of evolution
Rank order: Cat, Human, Bacteria
#10
Bacteria
Cat
Human
Fastest Slowest

23. Extinction
all members of a species die.
occurs when a species does not have the right adaptations to survive in the environment.
#11
What is it called when there are NO members of a species alive?
Extinction

24. Dinosaur Extinction One Theory:
An asteroid hit the Earth and sent up a cloud of dust which blocked sunlight for several years.
This caused climate change and killed many plants.
Dinosaurs were not well adapted to survive the changes.

25. Mrs. Henderson thinks this is the real reason dinosaurs went extinct!

26. What species are extinct?
#12
What species are extinct?
Dinosaurs
Dodo Bird
Saber tooth tiger
Woolly Mammoth
Plus Many Millions More!
(90% of all species that ever lived have gone extinct)

27. What is an endangered species?
#13
a population of organisms which is at risk of becoming extinct
Few in numbers
Threatened by changing environment
Threatened by predators
About 40% of all organisms are endangered, but only a few of the many species at risk of extinction actually make it to the endangered species list.

28. Examples of Endangered Species
#14
Panda
Eastern Tiger Salamander
Cougar