Over long periods of time variations in a species occur in a population, so the later generations are distinct from ancestral ones. In this time a new species may appear. Geographic location and selective pressures also contribute to the formation of a new species. If there is a natural barrier, (mountains, oceans etc) species will begin to adapt to the different environments, thus causing basically a new species such as the Galapagos finches. An important thing to emphasize is that natural selection is the individual while evolution is the population.
Darwin’s evolutionary theory is made up of four forces which are mutation, gene flow, gene drift, and finally natural selection. In the example of the Grant’s finches, the founder effect, a.k.a. genetic drift, is clearly described in the Natural Selection in Action: Galapagos Finches handout when it said, “This small founder population to survived and reproduced, and through genetic drift and natural selection accumulated sufficient variations over time to establish a variety of new species.” It is important to understand that the process of natural selection is closely linked to the environment a particular species inhabits. In the case of the Grant’s finches, there was described to be fourteen species of Galapagos finches, which evolved from a common ancestor. The Galapagos finches is a prime example of adaptive radiation because the Grant’s study displayed how the shapes of the finches beaks varied in order to best equip them for the differing habitats and diets they had.
Lamarck- Lived from 1744-1829. Remembered for the incorrect proposals to explain how evolution occurs. By comparing living species with fossil forms, he had found what appeared to be several lines of descent; each differed by age and time. His two key principles are use and disuse, which was the idea that parts of the body that are used more become stronger and larger, and inheritance of acquired characteristics, which stated that an organism could pass these modifications to its offspring. Also though that evolution happens because organisms have an innate drive to become more
Therefore, the role differences we observe are more of a product of our biological inheritance than acquired through socialisation. As the evolutionary approach is a biological one, it suggests that aspects of human behaviour have been coded by our genes because they were or are adaptive. However, a debate of this approach is the nature vs. nurture approach, nature supporting the evolutionary approach being that we have evolved through survival value and its ability to increase an individual’s opportunities to pass on their genes, an example showing this was Bowlby’s theory of attachment – concerning the role of evolution is the explanation of stress as an adaptive response to environmental pressures. Animals born without such responses die quickly. Nurture, on the other hand, is a view proposed by the social approach suggesting behaviour is affected by experience and environment.
The distinction between homology and analogy turns around the two most fundamental principles of evolutionary biology: descent with modification from common ancestors and adaptation. Darwin’s Origin of Species is a landmark in biology not only because it provided a natural mechanism for adaptation, but because it constituted an argument for descent of all organisms from common ancestors. The ability to distinguish between homologous and analogous structures forms the basis of this evidence. Homology refers to similarity between characteristics in different species of organisms. Analogy refers to different structures which perform the same function.
Evidence will be presented to illustrate the strength of each theory. Finally the main arguments of this essay will be summarized and will conclude that human language cannot be fully explained by evolution. It will end with suggesting that these theories have to be seen as provisional, due to the possibility of new findings. The growing interest in the origin of language can be seen as the outcome of significant technological changes in various scientific sectors. When genes and DNA were discovered in 1953, Charles Darwin’s theory of evolution has been supported in many aspects.
For example; by studying the skeletal and muscular structure in the Hawaiian honeycreeper, scientists were able to find similarities and could confirm that the current 23 species of honeycreepers all evolved from one ancestral species. This is a type of divergent evolution called adaptive radiation, which occurs when a species inhibits a habitat where there are few competing species. The other type of evolution is convergent evolution, which is where two seemingly unrelated species become more and more alike in order to survive in similar environments. The final type of evolution is coevolution. This is where two or more species that are in close interaction with each other change together, such as predators and their prey, or between plants and the animals that pollinate them.
Incident the views of Darwin coincided with that of Wallace and he was prompted to write a book "Origin of species" in which he was vividly explained "Theory of natural selection". Popularly his theory is known as "Darwinism". Darwin's theory is based on the following fundamental facts: (1) Over production (2) Struggle for existence (3) Variation (4) Survival of the fittest and (5) Natural selection (1) Over Production: Every plant and animal has a tendency to produce in geometrical progression (Malathian concept). If all the offsprings of an organism survive, then in a few generations the whole earth will be occupied by the individuals of a single species. Some example of over production can be cited as: i.
Besides criticizing evolution, Creationists are seeking scientific evidence of their own to support the creation account in Genesis. Both the idea of creationism and the theory of evolution have promising evidence to support each topic, therefore it should be left up to the character judging the situation to decide which idea is more valid. Darwinian evolution is primarily based on the process of natural selection. Surviving individuals, which vary in some way that enables them to live longer and reproduce, pass on their advantage to succeeding generations. Part of the proof of evolution is in the fossil record, which shows a
In my opinion for this to fully come about the groups must adhere to some type of inbreeding in order for the species to survive. And if so, would it not yield to the same gene but mix over and over not to cause a new species but to create a mutation that would be phase out by natural selection. According to Johanson the following chart illustrates these point of the model.