Blog #4 -Describe the three types of selection: directional, stabilizing and disruptive

Directional selection: is a mode of natural selection in which a single phenotype is favored, causing the   allele frequency to continuously shift in one direction.

Stabilizing  selection: is a type of natural selection in which genetic diversity decreases as the population stabilizes on a particular trait value.

Disruptive selection: describes changes in population genetics in which extreme values for a trait are favored over intermediate values.

Blog #3 Microevolution

Microevolution is a change in gene frequency within a population. The three step processes is mutation,  gene flo, and genetic drift. Natural selectionis one way variation occurs. Another way is genetic basis of a phenotype becomes more common in a population. The last way is if adaption occur within a population.

Blog # 2 Why is fossil record hard to interpret?

Since Darwin the fossil record has been pushed back to between 2.3 and 3.5 billion years before the present.   Most of these Precambrian fossils are microscopic bacteria or microfossils. However, macroscopic fossils are now known from the late proterzoic. The ediacara dating from 575 million years ago contain early multicellular eukaryotes. The fossil record and the form of the basis of the science of biostrastratigraphy or the age of rocks based on the fossils they contain.

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 happens when there is a variation of inherited traits within a population. I think that from this, Evolution is a theory because it is not guaranteed to happen such as laws happen all the time. Theories are predictions on what will happen and laws are what will happen. Evolution will not always happen it is more a prediction.