Food Pyramid: Blog # 6

I believe that the carbohydrate, or grains, level of the food pyramid is the most important. Carbohydrates give the body all the energy it needs. Without energy humans would not be able to survive. Protein can strengthen the body and give energy but the most energy comes from carbs.

The Cause of Extinction: Humans; Blog # 5

There have been five mass extinctions in the history of the Earth. Most of them where caused by natural climate change. The others are thought to have been caused by either the movement of techonic plates, volcanoe erruptions, or a collition between Earth and a comet. But it is thought that a sixth mass extinction is rapidly headed towards Earth. It is also believed that humans are causing this extiction. The things that humans are doing to upset the ecosystem are transforming landscapes, introducing alien species to enviroments, the overexploitation of species, and polution. These things are quickly changing the Earths climate, and if history is to repeat itself (as it allows does) when the Earth's climate changes quickly a mass extinction is bound to happen.

This Is My Selection (Blog #4)

Describe the three types of selection: directional, stabilizing and disruptive and give an example of each in your own words
Directional, stabilizing, and disruptive selection are the thre types of natural selection.
Directional selection is where a single trait is favored causing the frequency of the trait being dominant greater. The trait maybe recessive but with directional selection the recessive trait is favored so eventually it will become fixed.

             
 An example of directional selection is the fast trait in hunting dogs. Dogs that hunt need to be fast to catch their pray so their genes began to allow them to be faster and faster.

Disruptive selection is where two extreme sides of a trait are favored over the intermediate trait. This means that the differences in the trait are very obvious, which creates two different species that grow in different directions.

An example of disruptive selection is the galapagos finches.

Stabilizing selection is where the diversity of a trait decreases and the species has the same trait.

An example of stabilizing selection is a syberian huskie.

Blog #3

Explain what microevolution is? What are the three ways that variation occurs?
Microevolution is evolution an a small scale within a single population. It cannot always be seen in a species, it sometimes only effects how a species survives.
The three ways the variations occur are through mutation, gene flow, and natural selection.
Mutation is where some genes randomly mutate into different genes.
Gene flow, or migration, is where different genes enter a population through reproduction.
And natural selection is the idea that the strongest survive and the weak genes die off.

Blog #2 Fossils

Fossil records are hard to interpret because no two fossils are the same. Fossils come in many different sizes, shapes, and qualities. Some fossils have many pieces missing, that makes it very hard for scientist to determine what the species was and what its ancestors were. And without the fossils being the same shape or size scientists may not be able to put together that the two species are similar or related. Also if a fossil is small it can be damaged making it hard to interpret.   

http://www.thedarwinpapers.com/oldsite/number5/darwin5.htm

Blog #1 Evolution

 Evolution is not a law because laws can be tested in a lab and be proven completely true. A scientist cannot go into a lab and reproduce evolution in a test tube or in a box. Evolution took thousands if not millions of years to happen. Plus the mechanisms behind evolution are not widely excepted.

Blog # 13: DNA

DNA has changed the way police and federal agencies look for evidence, collect evidence, eliminate suspects, and how they investigate crimes overall. Not to long ago investigators could only put a criminal at the spot of the crime through eye-witness reports, and if no one saw the crime there was not much the investigators could do. But with the use of DNA testing if any partical of the criminal's body is left at the scene, and is picked up by csi units, it can be matched to the criminal. So DNA is able to put the criminal at the scene without a witness.

The two main types of DNA testing are PCR and RFLP. IN the PCR testing two pieces of the DNA strand are continously copied then at a certain point the copying is stopped. In RFLP testing restriction enzymes cut the DNA in specific sequences. When the enzymes cut the DNA the strands are at different lengths which can be prepared for electrophoresis.