Written Assignment 1
Supercontinent-Cycle Hypothesis
The supercontinent cycle is principally a geologic sequence where the Globe's continents alternatively join into a solo supercontinent, fragmented into several continents, then combine again. The cycle is projected to be roughly 300 - 500 million years in length. The supercontinent cycle is basically the outcome of geometry, bearing in mind that nearly 29% of the Globe's surface is made up of continents spread on tectonic plates that move in an unevenly haphazard fashion. After a given period of time, these continents are believed to ultimately combine then stick. However, they do not stick unceasingly since rifting actions among the continental plates make them detach from each other again, hence the supercontinent cycle carry on (Wilkins 2011).
Effect of Supercontinent-Cycle Ecological and Climatic Changes
The Earth's typical weather might be strangely different liable to where the Globe'scontinents are in the supercontinent cycle, as well as their location on the surface of the Earth. For example, in case a continent has stuck near a pole, such as the Antarctica, it might develop an ice sheet that is continent-wide hence suggestively lowering temperatures all over the pole. Heat is absorbed by the icy water from equatorial currents, dropping global temperature. Generally, the world’s coastsincline to be foggier places, hence most favourable to life. When landmasses in the world are at the supercontinent stage of the supercontinent cycle, coastlines in the world are reduced, and the middle of the supercontinent changes into a huge desert.
An Alternative Hypothesis
Supercontinent cycle does not account for the changes seen in oceanic basin and thus is not a comprehensive hypothesis. The Wilson cycle, is an alternative for supercontinent cycle and is the opening and closing witnessed in a distinct oceanic basin. The Wilson cycle hardlyharmonizes with the timing observed in a supercontinent cycle. Moreover, both supercontinent cycles as well as Wilson cycles were engaged in the formation of Rodinia and Pangaea (Wilkins 2011).
Possible Animal and Human Reactions
Diversity In terms of human and animal populations, as quantified by the number of distinct families, characterizes the supercontinent cycle in a noble way. This is because the principal tool for evolution is basically natural selection between varied populations. As genetic drift come about more often in small populations, it can be noted that diversity is an outcome of isolation. Less diversification is as a result of less isolation, and takes place when the continents unite, creating both a single continent as well as a single ocean characterized by one coast.
African Fossil Record
The African fossil record is used in sketching the purported human evolution from primate lineages. The fossil finding is composed of associated and sequestered adult teeth, a kid's mandible piece, two fractional cranial bases, as well as seven rubbles of a left arm. They characterize species remains that lies so adjacent to the discrepancy between the ancestress to the African apes and humans (Stanford, Allen & Antón 2012).
Importance, Validity, and Historical Influence of African Fossil Record
Paleoanthropologists have been unsatisfied by the presence of two wide-ranging gaps in the fossil record. The first gap, recognized as the hominoid gap, can be traced back to 32 to 22 million years ago when referring to the evolutionary time-scale. This period is significant since it is during this age that evolutionists consider that the descendants of humans and apes were separating hence the rise of the monkeys. This time-frame is essentially lacking the hominoid fossil proof to support this supposed divergence. The second gap, the hominid gap, is equally disagreeable for evolutionary theory since it ranges from 14 to 4.5 million years ago, a time the ancestors of human group andtheaustralopithecine were apparently separating from the African ape ancestors, particularly the chimpanzees (Stanford, Allen& Antón 2012).
References
Alasdair Wilkins (2011). A history of supercontinents on planet Earthhttp://io9.gizmodo.com/5744636/a-geological-history-of-supercontinents-on-planet-earth
Stanford, C. B., Allen, J. S., & Antón, S. C. (2012). Biological anthropology: The natural history of humankind. Delhi: PHI Learning Private Ltd.
