Transcript Speciation

Speciation
…is the formation of a new species as
a result of gradual changes within a
population.
3 events lead to speciation:
separation, adaptation and division.
1. Separation
• Part of a population becomes
separated from the rest.
• They may be separated by a
Geographical isolation like a canyon,
river, a mountain range, or being on an
island.
Other kinds of separation are…
• Ecological isolation –
Species are in the same
area but live in different
habitats.
• Temporal isolation –
Species are in same
area but are active at
different times of the
day or reproduce in
different seasons.
2. Adaptation
• After the groups are separated, each
group continues to be affected by their
environment:
–Different traits can be favorable or
unfavorable in different environments.
–Over many generations, different traits
may spread through each population.
3. Division
• The 2 separated
populations can become
very different from each
other.
• With time the members
of the 2 populations may
be unable to interbreed
successfully.
http://www.floridapanthernet.org/index.php/handbook/history/range_of_the_florida_panther/
http://news.discovery.com/big-cats/
Fig. 23.6
Four species of leopard frogs: differ in their
mating calls.
These squirrels live on opposite sides of the
Grand Canyon.
The Channel Island Fox
The California Grey Fox