Question 1 – Definition and explanation of natural selection
Answer 1
Natural selection is a process in nature that enables organisms that are better adapted to their environment to produce more offspring and to survive. It is also defined as a process by which traits that are heritable for an organism to reproduce successfully and become common in a population over several generations. Natural selection theory has been believed to be among the main process that brings about evolution.
Some individuals may reproduce and survive more successfully than others because of different factors and genetic variation population of organism. Natural selection may also act as an observable organism characteristic and on the phenotype. It has also acted as a cornerstone for the modern biology. Natural selection was introduced in 1859 by Darwin and he defined and described it as an artificial selection that was being used by individuals to systematically select plants and animals with traits and favored them for reproduction.
How natural selection is applied and understood in accounting for change over time using hominid evolution
Hominid evolution has been used as an example in the application of natural selection. Hominid evolution is the human evolution and it explains the evolution and the origin of Homo sapiens. It explains the study and the evolution of hominidae family and great apes. Modern humans are included in the family of the hominid evolution. It explains the existence of Homo sapiens who evolved from the Homo erectus.
Natural selection has led to hominid evolution that has resulted to Homo sapiens who is the modern human. A comparison of the genes that was made between human and the chimpanzees suggested that the genes have grown rapidly and there are many changes that have occurred within a given time. The differences between the humans and the chimpanzees and the variability within the humans suggest the involvement of the natural selection process. This is because it seems as if some genes were favored and the probability of reproduction and survival increased. The natural selection theory has been seen as the one responsible for the rate of evolution that has increased. Genes are regarded as the blue prints for proteins and they cause change in the sequence for amino acid as a result of positive natural selection. The human genome that has developed through the hominid evolution has been patterned by the natural selection that has played an important role in hominid evolution.
Answer 2
Natural selection can also be applied for change over time as Dawkins, (2006, p. 46-122), suggest, by both the human and the animals. This can be applied by the rate at which the birth rates are controlled. Population growth is always and naturally controlled by diseases and starvation. Dawkins believed that if the population for the animals or the humans is too big, a room to breed in for the species will not be available and the genes will not be retained. Natural selection can be applied to retain the birth rates because the groups that succeed in retaining their birth rates get a better chance of passing on their genes to other groups. Human select the children they bear by birth controls and this accounts for change and prevents the population growth. This can be termed as the use of artificial selection. By birth control, the children who are born become healthy and they are able to get other children who are strong.
Question 2 – Evidence utilized by Paleo – anthropologist to support that contemporary humans have evolved over time from earlier forms.
Answer 1
Paleo anthropology is the study of genus Homo sapiens and its extinct members through the means of fossils remains from the ancestors. One of the evidence that has been used by Paleo anthropologist to support the evidence that the humans have evolved over time from earlier forms is the presence of the ancestors due to the original human fossils that have been presented. Based on the fossils evidence, the paleo anthropologist believe that the hominid and panin were the same and they diverged about 5.4 million years ago and the panin became the Chimpanzees and the hominid evolved and developed to be the modern humans. They think that the evolution happened because of environmental conditions and the dietary demands. The fossils evidence has been examined from the species that existed after and before the split.
The anthropologists have made several technical achievements and they have successfully extracted the DNA of the Neandertal mitochondrial. The DNA that has been extracted for the first time does not match with the modern human DNA and there is a great difference. This shows that the modern human and the Neandertal were related but not very closely related. An example is the Homo fossils that were recently found in Spain and they give evidence that supports the evolution of human over time. It is a homo species and it has been named Homo antecessor by the people who discovered the fossils. Another example is the fossils of the upper jaw that belonged to the genus homo that was found which shows the existence of Homo erectus and the Homo sapiens. The hominid fossils give the evidence that the humans have evolved from the earlier forms to the current modern humans.
Answer 2
The paleo anthropologists have also used the last common ancestor to support and document their claim that human has evolved over time from different forms. The last common ancestor is used to show how evolution has taken place through varying species. The fossils have been studied by the scientist and a linear progression has been seen from species to species and it has been concluded that one form of life over time became another form. A situation has been identified where a given species branched into two. One of the forms that branched from the species evolved and developed to become the modern human. The last common ancestor shows that the humans were not as they are, but they have evolved over time from their earlier forms. The last common ancestor that existed between the human and the Chimpanzees is the one that splinted to hominid and panin. This made the beginning of the human evolution differently from the Chimpanzees. The hominid has gone through various steps over the years to become the modern human and the evidence has been clear through the discovery of the fossils in the early years and also in the recent years. Some of the fossils that have been found recently include the lower and the upper jaw bone, teeth, skulls and partial skeletons.
Question 3 – Reasons why the study of non human primates is central to the hominid evolution understanding
Answer 1
The study of non human primates is central to the understanding of the hominid evolution because it gives clues concerning the human nature, the non human primates are similar to the human primates in a great way and it helps understand the human characteristics.
- One of the reasons why the study of non human primates is important to the understanding of the hominid evolution is that the study help in giving clues about the species that led to the modern human and they also give clues concerning the human nature. This is because the non human primates are the relatives who are closest to the humans and study of the non human primate gives insight on the kind of animal human is about. The non human primates are the recent common ancestors of the human primates and they have more traits in common than in other non primates. According to Owen, (2008, p. 1-10), the reasoning by homology suggests that the time that has been taken to evolve and have the difference is not much, and that is why there are similarities. The human primates and the non human primates split from the same ancestor recently and this is evident because of the homologous trait that is similar for both species. A trait that may be found in non human primates may be important for the human primates because they may have inherited the trait from the common ancestor.
- The non-human primates are similar to the human primates in a great way than the other kind of animals even without the phylogenic relationship. This makes the study of non human primates to be central to the understanding of the hominid evolution. The basic design is similar and the living environments are also similar. The non-human primates who are living are similar to the human primates ancestors in that the exposure to selection pressure that were adapted were similar. Their study provides a model that is reasonable for accessing how the early humans who are the human primates ancestors were affected by the selection pressures. The study also helps in knowing the things that worked for the primates and identifying that the same could have worked for the human primate ancestors.
- The study of non human primate is also important in the understanding of hominid evolution in that the human characteristics will be understood through the analogies of the non human primates. This is possible through the study of the evolutionary theory which helps in understanding the features that include behavior and biology of the non-human primates. If the evolutionary theory of the non-human primates is used in the right way, then the information will help in explaining the sequence of changes that has been taking place to modern human from the early ancestors.
Answer 2
The characteristics of the primates are similar because they are all one kind of mammals. The study of non human primates is central because it helps to understand the mechanism brain function of the non human primates. The study also helps in understanding how the brain performs and functions depending on the mechanism. The aim of the study is cognitive neuroscience and it establishes the relationship that intervene the interference. The relationship helps to understand the hominid evolution that exists in that the human primates are compared to the non human primates.
The study can also give details and tell about other extinct ancestors. An example may be when relatives and descendants of a species that is extinct find a trait that is shared by all. The extinct species can posses the trait probably because it is a descendant of the same common ancestor with the human primates and the non human primates. This can give the people who are studying the non-human primates the soft tissues traits and the behavioral traits of the species that are extinct without being seen in the fossils record.
Question 3 – Generally held Misconceptions concerning the evolution of hominid
Answer 1
- a. Organisms are always getting better
Natural selection is believed to weed the unhealthy genes from the genes that are healthy in the gene pool, but in some cases imperfect organisms has survived. Some of the examples of the organisms that are not perfect and they have survived without changes for a long time includes the fungi, crayfish and sharks. The organisms have adapted and they survive in their environment without having any improvements. There are other organism that have changed but not for the better. This has made it to be a misconception because not all organisms get better as time passes as it is believed in hominid evolution.
- b. Natural selection gives organism what they need
The natural selection depends on the genetic variants because they have no intelligence to know what the organism needs. The population reproduces if they have a genetic variant that is more suited to the environment. The population evolves because they reproduce more in the presence of a genetic variant. In the absence of the generic variant, the population survives with evolutionary change that is little. The misconception continues because natural selection is not intelligent to identify what is needed by the organism.
- c. Gaps in fossils disapprove evolution
Some organisms that exist do not have fossils. This is because the process of fossilization is not allowed by the conditions that exist. The lack of fossilization will create a gap in fossils in the records of evolutionary changes. There are transitional fossils that exist and a good example is the fossils of birds from their dinosaur ancestors. The whales have also had their fossils from the land mammals. This transitional fossil has been preserved and there are no gaps that exist to disapprove their evolution.
Answer 2
The whale evolution has brought the incomplete picture because the evidence presented on the evolution of the whales relies mainly on the dental records of the oldest fossil. They rely on very few evidences that are available and they include some teeth, a mammal skull at the back and two jaw fragments. As Listverse, (2008), there is no evidence that the fossils that were found belonged to a whale that was old or it belonged to an old mammal. The misconceptions continue to persist because most people do not believe in evolution. Evolution is not believed in by the biologists but they accept it to be able to explain biological organism unity and its diversity.
The misconceptions also continue to persist because it is believed to be a false dichotomy and God is not invoked in its explanation. Most of the evolutionary biologists belong to religious faiths of the world’s major religions and they accept that their religion belief does not conflict with the theory of evolution.
Reference
Dawkins, R., (2006), The Selfish gene. Oxford University, United States, pp. 46-122. Chapter 4, 7
Listverse, (2008), Top 15 Misconceptions about Evolution (Online), Available from <http://listverse.com/2008/02/19/top-15-misconceptions-about-evolution/> Viewed on 16 May 2011
Owen, B., (2008), Why anthropologists study non-human primates, and an introduction to our relatives, (Online), Available form <http://bruceowen.com/introbiological/201-08s-09-LivingPrimates.pdf > Viewed on 16 May 2011
