1. Introduction to Evolution
Question #1
What is your definition of evolution?
This is your definition, not anyone else in class.
Take about 2 minutes to think about what you are going to write (don’t write anything yet!).
Take 2-3 minutes to write your definition on a blank piece of paper.

2. Introduction to Evolution
Evolution can be described as “change over time”.
The evolutionary process is by which modern organisms have descended from ancient organisms.

3. Introduction to Evolution
Our definition of evolution:
The change in allele frequency (genetic make-up) in a population over time.
This can be caused by many factors in which we will discuss later.

4. Introduction to Evolution
Question #2:
Did humans evolve from monkeys? Explain.

5. Introduction to Evolution
Explanation:
Humans did not evolve from monkeys.
Humans are more closely related to modern apes than to monkeys, but we didn't evolve from apes, either.
Humans share a common ancestor with modern African apes, like gorillas and chimpanzees.
Humans are probably most closely related to two chimpanzee species: the common chimpanzee and the bonobo.

6. Introduction to Evolution
Scientists believe this common ancestor existed 5 to 8 million years ago.
Shortly thereafter, the species diverged into two separate lineages.
One of these lineages ultimately evolved into gorillas and chimps, and the other evolved into early human ancestors called hominids.

7. Introduction to Evolution
We are not the king of all species.
We all come from ONE common ancestor.

8. Introduction to Evolution
Key points to understanding the process of evolution:
This is not a religious topic.
This is a theory that is well-supported.
Remember, this is the explanation of a process that happens (and has been happening) to all biological organisms.
Have an open mind!!!!!!!

9. Charles Darwin
The individual who contributed more to our understanding of evolution than anyone was Charles Darwin.

10. Charles Darwin Born in England in 1809 (same day as Abraham Lincoln).
In 1831 set sail from England around the world on the HMS Beagle.
This would become one of the most important voyages in the history of science.

11. Charles Darwin
During his travels, Darwin made numerous observations and collected evidence that led him to propose a revolutionary hypothesis about the way life changes over time.
That hypothesis, now supported by huge body of evidence, has become the theory of evolution.

12. Charles Darwin
On this voyage, Darwin made many stops and observed and collected many species of plants and animals.
He began to realize that an enormous number of species inhabited the Earth.

13. Charles Darwin
Darwin was intrigued by the fact that all species were so well adapted to whatever environment they inhabited.
He was also fascinated by the many ways organisms survived and produced offspring.

14. Charles Darwin
Darwin was also puzzled by where different species lived and did not live.
Australia and Argentina have the same grassland ecosystem but are inhabited by completely different animals.
Ring-tailed Coati

15. Charles Darwin For Darwin, these patterns posed challenging questions:
Why were there no rabbits in Australia (yet) despite the perfect habitat?
Similarly, why were there no kangaroos in England

16. Charles Darwin
Darwin soon realized that living animals represented just part of the puzzle posed by the natural world.
Darwin collected many fossils on his voyage.
Some resembled organisms that were alive.
Some looked completely unlike any creature ever seen.

17. Charles Darwin As Darwin studied fossils, new questions arose:
Why had so many of these species disappeared?
How were they related to living species?

18. The Galapagos Islands
These island located about 1000km west of South America influenced Darwin more than any stop made during his voyage.

19. The Galapagos Islands
These island are located very close together but have completely different climates and ecosystems.
The smaller, lower islands are hot, dry, and barren of most vegetation.
The bigger, higher islands have greater rainfall and a higher abundance of plants and animals.

20. The Galapagos Islands
Darwin was fascinated with the land tortoises found in the Galapagos.
Darwin learned that these tortoises varied in predictable patterns from one island to another.

21. The Galapagos Islands
The dome-shaped shell tortoises are found on wetter islands such as Isabela.
The intermediate shell tortoise are found on islands with a mixture of dry and vegetative ecosystems.
The saddle-backed tortoises are found on drier islands such as Hood.
Why?

22. The Galapagos Islands
Saddle-Backed Tortoise

23. The Galapagos Islands
Darwin also examined many different types of brown birds foraging for seeds.
He noted a difference in beak shapes on many of these birds and thought they were all different species of brown bird (wrens, warblers, etc) at first.

24. The Journey Home
While heading home, Darwin spent a great deal of time thinking about his findings.
Darwin had observed that the characteristics of many animals and plants varied noticeably among the different islands of the Galapagos.

25. The Journey Home
After returning to England, Darwin began to wonder if animals living on different islands had once been members of the same species.
According to this hypothesis, these separate species would have evolved from an original South American ancestor species after becoming isolated from one another.

26. The Journey Home Was this possible?
If so, it would turn people’s view of the natural world upside down.