112lect16 - GY 112 Lecture Notes D. Haywick (2006) 1 GY 112...

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GY 112 Lecture Notes D. Haywick (2006) 1 GY 112 Lecture Notes Fossil Evolution part 2 Lecture Goals : A) Definition of Evolution B) Darwin's law of natural selection gradualism, punctuated equilibria C) examples of evolutionary development Textbook reference: Levin 7 th edition (2003), Chapter 4; Levin 8 th edition (2006), Chapters 6 & 8 A) Definition of evolution Last time we met, we dealt with the origins of life on this planet (or possibly within the solar system). There have been some pretty interesting ideas about life being associated with astronomical things (e.g., comets), but even if there is life "out there" in our solar system, it will be primitive. The earliest life on this planet was prokaryotic . Eventually cyanobacteria (prokaryotic beasties but with chlorophyll) developed. Stromatolites are an example of this type of life form. Prokaryotic life forms lacked bound nuclei and organelles. Later life forms were characterized by those features. These were the eukaryotes and their arrival marked the start of rapid evolutionary change on this planet. But just what is evolution ? At its most elementary level, evolution simply means “change”. But not all change (in beasties) is evolutionary. Evolutionary change is the transgenerational variation that occurs when social or biological forms adapt to their environment . This means that to be considered evolution, the changes must be passed on to future generations. First a Disclaimer: There is no more single controversial topic in Alabama than evolution (that and which football team (Alabama or Auburn) is better). Everyone has their own beliefs and feelings about where we came from and how life first started on this planet. We are stronger people when we respect each others beliefs. In this class, we are interested in Science’s understanding of how things work. Scientists (and I’ve mentioned this many times already), must forever remain skeptical about everyday occurrences. They must constantly test their hypotheses and ideas about how things work. If an idea survives a test, that idea is retained. If it fails, it is abandoned or modified to better fit observations. Like life itself, scientific reasoning is a matter of survival of the fittest (ideas). Science and religion will never be totally in sync. Scientific hypotheses must be testable; religious beliefs relies on faith alone. I say why bother relating the two together at all. I like apples and oranges, but I don’t try to equate the two of them together (flavor- wise). Sometimes my needs are met by an orange. Sometimes I need an apple.
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This note was uploaded on 02/04/2012 for the course GLY 112 taught by Professor Haywick during the Spring '12 term at S. Alabama.

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112lect16 - GY 112 Lecture Notes D. Haywick (2006) 1 GY 112...

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