1. Or, a scientific explanation for the diversity of life on our planet.
Evolution Notes
Or, a scientific explanation for the diversity of life on our planet.

2. Organisms have characteristics that help them survive well in their environment.
Example: Many animals have skin or fur that is the color of their surroundings or have thick fur in a very cold environment, etc.

3. Adaptation
These characteristics that help organisms survive (and reproduce) in their environment are called adaptations.
Example: Modern whales have a lot of blubber that helps them stay warm in a very cold ocean!
Mmm,
toasty warm

4. Question: What is the offspring of a horse and a donkey called?
Species
A species is a group of organisms that can mate with one another to produce fertile offspring (offspring that can have more offspring).
Example: A horse and a donkey are each fertile, but if they have an offspring together, the offspring is NOT fertile (meaning it cannot produce another generation.)
Question: What is the offspring of a horse and a donkey called?

5. + =
Fertile Horse
Fertile Donkey
Sterile Mule

6. Female Tiger
Male Lion + =
Female Liger or Male Liger

7. Male Tiger
Female Lion + =
Tigons

8. Evolution Evolution is change over time.
A species can go through so many changes that it becomes another species.
Example: If all living things share a common ancestor, then each species today has gradually developed different features to distinguish the species.

10. How do we know about evolution?

11. There are 6 lines of evidence for evolution
Fossil Record
Biogeography
Vestigial Structures
Morphology
Modern Genetics
Drug Resistance

12. Diversity
Diversity is a measure of the number of species an area contains.

13. FACT: Tropical regions have much higher diversity (or more different species) than cold, polar regions.
Squaaak! Life is
good with all
these folks around!
Jeesh,
it’s hard
work living
up here.

14. Fossil Record
The fossil record shows evidence of past living things found in layers of the earth’s crust.
Not every organism that scientist think existed can be found as fossils because most of the time dead organisms don’t form fossils.

15. Fossil Record
From the fossil record, scientists can see that life has not always been the same.
Example: This record shows that a certain tree-dweller becomes two species!

16. Vestigial Structures
A vestigial structure is a part of an organism that was useful in the past but now is not.
Example: For example, whales have small bones which seem to have become smaller over time. These bones may be remnants of hind legs which whales no longer have.

17. Question: What do humans have that we no longer use?

18. Similar Anatomy Looking at the overall body and similar body parts
Compare eyes to eyes or ears to ears
Whale Eye Frog Eye Dog Eye

19. Similar Skeletons
When we compare the skeletons of different animals, the structure of their bones look very similar.

20. Similar DNA
DNA of organisms that are related (have evolved from one another) is similar.
The DNA of closely related organisms is more alike than organisms that are not closely related.