Speciation and Subspecies

1
Speciation and Subspecies

• Looking at rattlesnakes of the east coast

2
New species

• As organisms accumulate more differences between
  groups, the groups become less and less alike.
• This change is called divergence
• Divergence will eventually lead to the creation
  of a new species.

3
Subspecies

• As a group of organisms diverge from the original
  they eventually will become a subspecies.
• A subspecies means the two groups are genetically
  different, but can still breed together.

4
Examples of Speciation

• Timber rattlesnake of the east coast are
  identifiable to their state based on color.
• Dark ones..
• New York

5
Examples of Speciation

• Medium tone snakes
• Pennsylvania

6
Examples of Speciation

• Light tone snakes
• Virginia

7
Examples of Speciation

• The darker the snakes the colder the climate.
• How did this variation become noticeable ?
• What factors drove these changes?

8
Subspecies

• Right now, even though there are genetic
  differences all of the populations of timber
  rattlesnakes are able to breed if they came in
  contact with one another.
• Therefore they are not considered a subspecies or
  separate species.

9
Examples of Speciation

• If these population continue to change what will
  happen?
• What will be the first step in speciation?

10
Speciation

• Speciation is the point at which two groups of
  individuals are no longer able to breed.
• Making them a new species.
• What is the time frame for speciation to occur?