Blog #4

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

• Directional Selection: Directional selection is selecting the individual with the most extreme variations in traits in a population. An example is choosing the fastest greyhound dog among a group of them. Then you pick the fastest one from their offspring. When you continue this, you end up with a really fast greyhound.
• Stabilizing Selection: Stabilizing selection is selecting the individual with the common, average traits in a population. An example is a Siberian Husky. If a Siberian Husky had heavy muscles, it would sink in the snow but if it had lighter muscles, it wouldn't be able to pull the sled. So choosing a medium Siberian Husky would be able to move through the snow and pull the sled.
• Disruptive Selection: Disruptive Selection is selecting the extreme traits in a population that would survive a sudden change in the environment. For example, when the Earth was hit by a meteor, there were large tidal waves,  increasing number of earthquakes, inadequate supply of food, and little oxygen. Larger animals would not have survived in this because they needed a lot of food and oxygen, but evidence shows that disruptive selection actually picked the traits that would help the animals in these conditions, thus making them survive.

Blog #4

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

• Directional Selection: Directional selection is selecting the individual with the most extreme variations in traits in a population. An example is choosing the fastest greyhound dog among a group of them. Then you pick the fastest one from their offspring. When you continue this, you end up with a really fast greyhound.
• Stabilizing Selection: Stabilizing selection is selecting the individual with the common, average traits in a population. An example is a Siberian Husky. If a Siberian Husky had heavy muscles, it would sink in the snow but if it had lighter muscles, it wouldn't be able to pull the sled. So choosing a medium Siberian Husky would be able to move through the snow and pull the sled.
• Disruptive Selection: Disruptive Selection is selecting the extreme traits in a population that would survive a sudden change in the environment. For example, when the Earth was hit by a meteor, there were large tidal waves,  increasing number of earthquakes, inadequate supply of food, and little oxygen. Larger animals would not have survived in this because they needed a lot of food and oxygen, but evidence shows that disruptive selection actually picked the traits that would help the animals in these conditions, thus making them survive.

Blog #3

Blog #3 Explain what microevolution is? What are the three ways that variation occurs?


Microevolution is small-scale genetic changes that lead to new subspecies. Microevolution ocurs from mutation, migration, and selection. Mutation is when there are random changes in the organism's composition or number of DNA molecules in their cell. Selection is when "weak alleles" that hurt the chances of an organism's survival are eliminated from the gene pool and the adaptive alleles that help an organism's survival are passed to a larger proportion of the gene pool. Lastly, migration is when organisms move into or out of a population and it effects the gene pool when the organisms carry a different genotype different from the population because the effect is greater on allele frequencies than if these organisms carry a similar genotype. 

Blog #2

Blog # 2 Why is fossil record hard to interpret?


Fossil records can be hard to interpret because sometimes the older fossils that are about more than three billion years old becomes fragmentary. Also some fossil records that are in mountainous areas are eroded by wind or water,  destroying the fossil. Fossils are also unreliable because not all bones of the same animal survive equally the same such as larger lightweight bones deteriorate more quickly and aren't that fossilized but small, delicate bones are crushed and carried away. Other fossils may only have a bone or two, making it hard to interpret what kind of organism it came from.

Blog #1

Evolution is a theory not a law because it has yet to be proven and supported with evidence. The definition of a scientific law is that it is a phenomenon of nature that has been proven while the definition of a theory is that it is an explanation of scientific observations. Evolution fits the definition of a scientific theory because it is an explanation of what has been observed and tested over thousands of years. There's also not a lot of information to prove evolution since it can't be repeated.