Directional selection is when one extreme phenotype is favored over other phenotypes. This eventually leads to the selected phenotype to be passed from generation to generation. In contrast, disruptive selection is when two extreme phenotypes are favored over other intermediate phenotypes. An example for directional selection can be found when it comes to the color of mice. Mice can range anywhere in color from white to dark brown, in directional selection, it appeared more mice that were brown were surviving so in turn, more brown mice were reproducing and white mice were becoming rare. Disruptive selection is when both the dark brown mice and the white mice are being favored over the lighter brown, causing the colors in between to be phased out. In the process of natural selection, organisms most fit for reproduction will survive. In the case of strains of bacteria, the bacteria will only be able to thrive and reproduce if the antibiotics are not able to kill it. Bacteria has a variability in that some strains are more unaffected by antibiotics than others. When certain bacteria are found to survive despite antibiotics, these bacteria will reproduce and pass on that trait because it makes then a more fit organism. The major evolutionary trends that allowed for aquatic vertebrates become terrestrial was the development of feet and legs rather than fins. When water was scares, aquatic animals would die out because the water was too shallow to survive, thus legs and feet were better adapted to get around in such environments. Aquatic plants, such as fern reproduce by having the sperm swim to another plant, plants became dependent on water in order to produce offspring. In order for this to be achieved, the eggs of the female had to be closer to the ground to enable the sperm to not have to swim as far. As plants evolved, their eggs became found on the top of the