Migration is the manner through which varied organisms often journey long distances looking for places to feed or reproduce. For instance, the monarch butterfly is one of such butterflies that tour several miles looking for places to reproduce or feed; the monarch butterfly consists of those species from North America and southern Canada. Early winter, the monarchs mate, lay eggs, and die; the eggs then hatch giving rise to caterpillars, which feed on milkweeds. Afterward, the caterpillars shed outer covers six times at some stage in the growth process and then they enter the pupa. In the pupa stage, internal organs degenerate and get changed by adult butterfly by the instances opening and giving rise to chrysalis. The new monarchs then attain adulthood during early or mid-summer and then reproduce completing their lifecycle. Further, their offspring that become adults during late summer remain infertile. As winter nears and daylight shortens, the monarchs that hatch late migrate to the south. Irrespective of the adult absence regarding early generations to show them direction, these monarchs often go back to the same region where their ancestors were before. In this case, temperatures drop to maintain semi-dormancy; however, temperatures start rising the monarchs become active, gather nectar, and start migrating to the north. As they grow, the monarchs mate and then migrate back to the northern region where they lay eggs and mate beginning the cycle all over again.
There are two core probable evolutionary scenarios that depict the consistency of birds having a common ancestor. The first idea indicates that ancestors had teeth before they lost along the evolutionary line. The second ideology ascertains that the shared ancestors did not have teeth while the reptiles got them as they evolved. To ascertain these ideologies, Fisher and Collar took outer layers of the embryo from the section that produces teeth; they founded a possibility that teeth could develop from these layers. Collar and Fisher concluded that if the chicken ectoderm induced by the mouse mesoderm produces teeth, then it could be easier to determine whether the chicken had teeth and lost them in the evolutionary line. In essence, development of teeth in the birds, especially the chicken required a favorable environment, for instance, teeth-inducing tissues obtained from mice. Despite the fact that the teeth emerged was not typically those for a mouse, they are atypical representing an outline of tooth in reptilian ancestors.
Origin of Life
According to Darwin, evolution has made different forms of life to emerge; he notes that evolutionary bases are founded on chemical means denoted by warm little tide pools. The idea was a bit political and seemed to spark the question of life originated. The controversies concerned spontaneous generation and reflected strong interests regarding the age-old question. For instance, the maggots in their larva form emerged from decaying meat and bacteria are often formed directly from matter that is decaying. Accordingly, if the living organisms often evolve from natural processes, then is appropriate to contend that life originates through natural processes too.
There are two schools of thought connoting the origin of life including abiogenesis and panspermia. In the former ideology, simple organic matter evident in living organisms emanate from chemicals implicated by geochemical evidence. Regarding panspermia, it is depicted that there were primitive microbes transported to the earth as meteorites or debris. However, this aspect if criticized asserting that cells could not have survived the temperatures through space. Further, several scientists including Bernstein, Sanford, and Allamandola claim that highly organized entities might be the ones that were transported to earth. To substantiate these claims, the question was broken into two sections and addressed by NASA according through a series of experiments.