Semester 2 : Blog # 6

Vegetable group is the most important group in the food pyramid. The reason why it's important is becauase vegetacbles usually gives people vitimans, to make people be healthy and fit. Without vegetables you won't have enough energy to excerize survive in life. Vegetables contain many vitamins and minerals though different vegetables contain different spreads, so it is important to eat a wide variety of types.

Semester 2: Blog # 5

I think the humans are impacting anothor extinction, the reason why I think this is becuase humans have been over populating the area, polluting the oceans, ruining many habitats for species, and killing animals for eating. Also eversince cars has been invented they have been polluting the airs and making the ozone layer decrease even more. So if the humans keep doing this to the Earth to the extreme, before you know it all the animals would disapear and the habitats like the forest would be gone which means the trees would decrease and the oxygen we need will affect us. Humans needs animals and oxygen in order to suvive. So without the essentials in life theres no way we can live including the animals.  

Semester 2: Blog # 4

1. Stabilizing selection favors the normal, the common, average traits in a population. Stabilizing Selection occurs when selection favors the intermediate trait value over the extreme values. Populations under this type of selection typically experience a decrease in the amount of additive genetic variation for the trait under selection. An example would be human birth, babies cnanot be born with really low weight or really heavy weight because it will lead to infant mortality. So thats why our bodies perfer medium weight.
2. Directional selection is when natural selection favors a single phenotype. It occurs when there is a shift in population towards an extreme version of a beneficial trait. An example for this selection would be A useful example can be found in the breeding of the greyhound dog. Early breeders were interested in dog with the greatest speed. They carefully selected from a group of hounds those who ran the fastest. From their offspring, the greyhound breeders again selected those dogs who ran the fastest. By continuing this selection for those dogs who ran faster than most of the hound dog population, they gradually produced a dog who could run up to 40mph.   
3. Disruptive selection, also called diversifying selection, describes changes in population genetics in which extreme values for a trait are favored over intermediate values. In this case, the variance of the trait increases and the population is divided into two distinct groups. An example for this would be the population of rabbits. The color of the rabbits is governed by two incompletely dominant traits: black fur and white fur. If this population of rabbits were put into an area that had very dark black rocks as well as very white colored stone, the rabbits with black fur would be able to hide from predators amongst the black rocks and the white furred rabbits would be able to hide in the white rocks, but the gray furred rabbits would stand out in both of the habitats and would suffer greater predation. As a consequence of the selective pressures of their environment, our hypothetical rabbit population would be disruptively selected for extreme values of the fur color trait: white or black, but not gray.