blog #5

There have been 5 major extinction events throughout history, are humans impacting the 6th? Why or why not?

Yes. Throughout history the five major events that have ended were cretaceous,permian , triassic, late devonian, and late ordovician is unviodable and can happen to humans today. Such as asteriod/comet impacts,climate changes,volcanic eruptions, sea level changes, and oxygen in the atmostphere. These causes can happen at anytime and thus happpening today wiping out millions of people. Humans, right now don't have the ability to prevent theese events from happening. Humans have been overexploiting lands, species, and overpopulation

Blog #4

Describe the three types of selection: directional, stabilizing and disruptive and give an example of each in your own words

During directional selection is when those that have some kind of unique trait are purposely chosen to mate continue those traits. Such as greyhound dogs are specifically known for their speed, if breeders chose the fastest dogs and breed them, they will be able to produce fast dogs.Stabilizing selection kinds of balance everything out because it produces the normal traits. It creates a cross between a big and small dog to a median size dog.Disruptive selection is similar to directional selection because it favors the unique traits but like it  sounds it happens quickly and help select extreme traits in order to survive. For 

example if birds with median sized beaks lost their food source,then disruptive selection would have to favor big or small beaks to survive.
 link location:
http://images-mediawiki-sites.thefullwiki.org/04/3/3/0/1793564074574269.png