Evolution
Chapter 15

How did humans, as well as as other species that are alive today come to their existence?

I. Evolution- is a change through time which is based on theoretical concepts & assumptions

                              -modern organisms have descended from ancient organisms

     Theory - a well supported, testable explanation of a phenomena that has happened

Charles Darwin - contributed to our understanding of evolution than any other individual

       -born in early 1800's, traveled around the world and collected evidence that led him to his hypothesis,

which became well known as the theory of evolution

       - Through his travels he came to see the diversity of life on Earth

       - He also realized that living animals only represented a small part of the puzzle of life

The Galapagos Islands

 - group of small islands located about a 1000 km off the west coast of South America

•        The islands had different climates
•        Even though the islands were close, there was a large assortment of plants and animals.
•        Charcteristics of many animals varied noticeably among the different islands of the Galapagos

James Hutton and Charles Lyell - known for their idea that the processes that changed Earth in the past are the same

processes that are occurring today

Lamarck's Evolution Hypothesis:

          -proposed the idea that organisms acquired or lost certain features depending on the amount of use of that trait

These traits could be passed on to their offspring and would lead to change in a species.

                    Lamarck's Hypothesis was incorrect in many ways!

Lamarck did not know how traits were inherited

Darwin's Ideas

Artificial Selection - nature provides variation and humans select the desirable traits

Adaptations are inheritable characteristics that increase an organism's chance of survival. 

          - The ability of an organism to survive and reproduce were key concepts to the process of evolution,

which helped define the Survival of the Fittest, or Natural Selection.

Over time, these changes in inherited charactistics of a population, increase a species' fitness in its environment

Darwin also believed in common descent, all organisms have common ancestry

Evidence for Evolution:

1. Fossil Record -

What is a fossil? great web site, "must see"

Fossils- are any remains of an organism preserved by natural processes
-types of fossils can include: amber, ice, bones, petrifaction, molds, casts, & imprints

2. Geographic Distribution -

       Similar organims can be found throughout different parts of the world.  Species were slightly different depending on the location of the organisms.