Day 37 Intro to Evolution
EVOLUTION!
-The word evolution means change over time.
-We can apply this to anything. We can say that a band or musician's career has evolved. This does not mean that it got better it just means that it has changed over time.
-EVERYTHING CHANGES
-In biology, evolution means change of allele frequencies over time. Think of this as a change in genes over time
In order to pass on your genes you need to reproduce. Evolution is all about who reproduces
-The four mechanisms of evolution refer to who chooses who gets to reproduce
The four mechanisms of evolution
-Natural Selection
-Is when nature chooses who gets to reproduce
-Survival of the fittest
-Artificial Selection
-Humans choose who gets to reproduce
-How we turned wolves into Chihuahuas
-Sexual Selection
-The opposite sex chooses who gets to reproduce
-Usually goes against natural selection
-A peacock's feathers and a frog's croak are good examples
-Genetic Drift
-This is the only one that is not a selection
-It is usually an accident
-You reproduce with what you have because they are the only options
-The only ones in an area (Founder Effect) or a disaster kills off most of the group (Bottle Neck effect)
-Evolution is different than speciation.
-Speciation is when one species turns into another species.
-Speciation uses evolution to describe its process but it is separate from evolution
-History of life
-The first cell hypothesis is the hypothesis that one cell turned into all life on earth. This is a hypothesis that uses evolution to describe how it happened but is not evolution.