Blog #4

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

Directional selection is a mode of natural selection in which a single phenotype is favored, causing the allele frequency to continously shift in one direction. Stablizing selection is a type of natural selection in which genetic diversity decreasesas the population stablizes on a particular trait value. Disruptive selection describes the changes in population genetics in which extremem values for a trait are favored over intermediate values. An example for directinal selection is breeds of dogs. Dogs are used for this example bcause you can use directional selection to see which dog can run faster. an example for stablizing selection is baby birth weight. Babies with low weight loses heat more quickly and can get ill easily. An example for disruption selection would be if different color skin rabbits were placed in dark or white spots. They would hide from predators and see which rabbits with the same skin would blend in.

Blog #3

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

Microevolution is the change in gene frequency within a population. One way that variation occurs is when crossing over occurs during meiosis. It also occurs when mutation alter the order of bases in the nucleotide DNA. Mutations are rare and most mutations are harmful, but some instances the new allele can be favored by natural selection.

Blog #2

Why is fossil record hard to interpret?

 Fossil record is hard to interpret because the fossil record becomes fragmentary and hard to interpret. Since the fossils have been there for at least 10,000 years or more, it would be very hard to notice the shape of the animal/plant. The fossil has to be broken down in order for the main part to be taken out.

Blog #1

Why is evolution a theory and not a law?

Evolution is the change over time in the proportion of individual organisms differing in one or more inherited traits. Evolution can be observed through changes in traits of a population over time.The theory of evolution is the framework that explains the observed changes of species over time. It best predicts the new observations that continue to be made in evolutionary biology.