Evolution – Vertebrate Anatomy Name: __________________________________
I. ___________________________________ - Change in the kinds of species on Earth over time.
A. an old idea - first suggested by the _____________________ - ______________________
B. still, though the idea of evolution had been around for a long time, no one had ever suggested
a means by which evolution could occur.
C. A Scientist named _________________________________ did come up with an idea as to HOW
evolution could occur, but it was WRONG
1 . Evolution of _______________________________________
2. ___________________________ and ___________________________
2. "stretched neck" - giraffe
D. Charles Darwin figured out a __________________________ by which evolution could occur.
1. Called it ___________________________________________
2. as a young man sailed on the ___________________________ around the coast of S. America and the
Galapagos Islands
3. There he observed organisms that were SIMILAR to those on mainland S. America, but
not the same. He wondered how these changes came about.
a. Example: ______________________________________
4. Came up with his idea which was not published until 1859.
5. Name of book: _______________________________________
6 . Very controversial
II. What Darwin said about Natural Selection - Mechanism by which evolution occurs
A. Organisms __________________________________ - more offspring are made than can be
supported by environment
1. This leads to ____________________________
B. Organisms are __________________________
1. VARIATION - differences that exist between organisms
C. Much variation in organisms is ______________________ (genetic)
D. since all organisms are different, some will naturally be better suited to their environment than
others.
Example: a white rabbit is better suited to the arctic than a brown one
E. organisms that have traits that better suit them for their environment than other organisms
will __________________________ other organisms and will ____________________ more
often than other less suited organisms
F. the well suited organisms will have _________________________________ than the ones who
are not so well suited
G. over time, the better suited organisms will out-number and out-compete the less well suited
ones.
H. ______________________________ - a characteristic that makes one better suited for one's
Environment (ex. of rabbit above)
I. If lots of SMALL changes in a population accumulate overtime, it could result that the population becomes so
different from its parent population that it can no longer reproduce with it's parent population. If this happens, it
would be considered that a NEW SPECIES had arisen.
1. This is called __________________________________
J. ________________________ - a group of organisms who can interbreed with each other and produce fertile
offspring.
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