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 mechanism of evolution that is not a selection

-It usually starts with 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)

Speciation

Speciation is when one species turns into another species.

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 life began on earth.

Evolutionary Structures

Homologous Structures

Analogous Structures

Vestigial Structures