1.+How+Do+Species+Evolve?+Galeza+and+Sicker

=How Do Species Evolve?=

Species
are defined as a group of individuals that actually or could potentially interbreed in nature. A good example would be dogs. As shown in the picture, there are many breeds and very different characteristics, but they can all interbreed because they are all the same species.



Interbreeding
is the mixing of different species or varieties of organisms to create an offspring with mixed characteristics. An example would be if you had a Carrion crow and a Hooded crow. They had offspring, and the children are a mixture of the two parents. This can help in the development of a new species.

**Speciation**
"Speciation is a lineage-splitting event that produces two or more separate species.", according to [|http://evolution.berkeley.edu]. In short, it's when 1 group of a single species is split into separate groups, and over time the groups change enough that separate species form.

There are 3 different types of speciation that can occur: Allopatric speciation, Parapactic speciation, and Sympatric speciation. Allopatric and Parapactic both start similarly, but differ over time. Here is a model of the 3 types:




 * Allopatric Speciation** is the most dominant mode of speciation. A physical barrier separates the group and they evolve differently. This can occur for many reasons, including genetic drift, but especially because of different environments. A good example of this is African Elephants. African Elephants have 3 subspecies because of a divergence due to their geographic isolation. Scientists now group this one species into West African elephants, Savanna Elephants, and Forest Elephants. Over time, these subspecies may evolve into separate species altogether.


 * Parapactic Speciation** is when a physical barrier separates the group and they evolve differently. Then, the barrier disappears, such as a river drying up, and the two new species come back together and interbreed. An example of this is the grass // Anthoxanthum //, which has been known to undergo parapatric speciation in such cases as contamination from a mine in the area. 1 group often separates by developing a tolerance for those metals.


 * Sympatric Speciation** is different than the other types. There is no barrier and the group stays together, but the group still develops into different species. This is uncommon is eukaryotic organisms, though not impossible. It is very common in bacteria.

For another example of speciation, this video is helpful in explaining the speciation of California Salamanders.media type="youtube" key="YCoEiLOV8jc?rel=0" height="315" width="560"

In the Future,
new light could be shed on how evolution works. It is very possible that a new way of evolving or new methods of species developing could be discovered, but the idea of speciation will still be the same. Whether the group separates or not, natural selection and the development of new species will occur over time.

**For Further Research and Sources Used:**
http://evolution.berkeley.edu/evosite/evo101/VSpeciation.shtml Wikipedia Google Images