Reconstructing Human Origins: A Modern Synthesis

1. Evolutionary theory describes how populations change over time due to changes in the gene pool. There are several mechanisms that can change a gene pool and allow evolution to occur. Natural selection, mutation, gene flow and genetic drift are some of the driving forces behind evolutionary change. Natural selection and genetic drift are the mechanisms that decrease genetic variation, whereas gene flow and mutation are the driving mechanism to increase genetic variation. Natural selection is basically the understanding that the environment can not support unlimited population growth, and not all organisms are able to reproduce to their full potential due to trait variation. For example, a black fly may

The four common forces of evolution are: mutation, natural selection, genetic drift, and gene flow. Evolution transpires when one or more of instances occur. Mutations are a random hereditary change of DNA capable of passing from the parent to the off spring within each person’s own DNA. Natural mutations occur when cells are copied and begin to divide. The Genetic drift is a random change in allele frequency from one generation to the next and will have a greater impact in smaller populations. However, the genetic flow is a separated population of species that come in contact and will begin to breed and exchange DNA but also works to decrease the variations between the two different kind’s species. Natural selection is the process that

The four forces of evolution are mutation, natural selection, gene flow, and genetic drift. Mutations occur when the DNA replication process makes an error, if the error is not fixed than the mutation will form. A lot of the mutations do not affect an individuals health, however, there are some that can cause damage. If the mutation makes the individual stronger or benefits them, then the mutation is capable of staying within the population through reproduction. Natural Selection is when a species adapts to its’ environment and thus is able to reproduce while the others who have not adaptive die out. Darwin calls this survival of the fittest, only the strong move on. Gene flow is the process of breeding with a different population that changes

Given enough time, one species may develop such different characteristics as its ancestors possessed that it becomes considered as another species. This assertion follows logically from the two principles of heredity and natural selection.

Natural selection leads to evolutionary change when individuals with certain characteristics have a greater survival or reproductive rate than other individuals in a population and pass on these inheritable genetic characteristics to their offspring. The gene pool increases when a mutation changes an allele so there is a new version of the gene and the mutation survives to establish in the gene pool either by genetic drift or positive selection. The gene pool decreases when an allele is eliminated from the gene pool by genetic drift or by negative selection reducing the productive success of those expressing the phenotype. In changing in the gene pool the possible combinations of phenotypic traits change and the population evolves.

Evolution in terms of biology is defined as decent with modification and can be explained by the rise in diversity from generation to generation based on changes in the gene frequency. When changes occur in an individual’s genome, known as mutations, they give the individual different characteristics that can have a negative, positive, or neutral effect. If the mutation better adapts the individual to the environment, that mutation can be passed onto a new generation. If the mutation weakens the individual to the environment, that mutation will not be able to withstand multiple generations through progeny. This mimics Darwin’s theory of natural selection, which states that the individuals best fit to the environment have a higher survival and reproductive rate. Over time, these mutations contribute to genetic variation within species (yourgenome).

One of the four processes for evolutionary change is a mutation. Mutation is when a mutation could occur which causes the trait to be different in the offspring than the parents’ trait. The second is migration, of the processes for evolutionary changes. Migration is when some individuals from a population might migrate to another population and that population would have more frequent trait then they were that their original population. The third one is genetic drift, of the processes for evolutionary changes. Genetic Drift is a mechanism that can be changed in the frequency of the alleles in the population due to random selection or chance, which is either the bottleneck effect or the founder effect. Natural Selection is when an individual

Genetic drift is non-directional, unlike other evolution factors. It is the result of the random sampling of alleles at each generation and its effects are most prevalent in small

Genetic drift is a natural phenomenon that occurs due to the randomness of natural breeding and reproduction within populations. Normally this occurs in smaller populations and leads to a fixation of alleles over time. Frequencies of the alleles change because of sampling error within a population and their reproduction from generation to generation. Genetic drift also tends to change populations a lot in a very quick amount of time. The amount of inbreeding and homozygotes increases in populations where genetic drift is present and the rate at which genetic drift occurs is not proportion to population size but is more common in smaller populations because there is already a smaller pool of alleles than in a larger population. Any population

Charles Darwin broached the theory of natural selection in his book the Origin of Species, which has been considered the basis of evolutionary biology to this day. Natural selection is when populations of a species evolve over the course of many generations. Darwin believed that species were not created separately, but instead, species were derived from one another. In other words, the evolution of species creates many variations among creatures, and this is because all of those species came from a common ancestor, and characteristics changed to increase the species chance of survival.

Genetic drift is a change in allele frequency over time (Larsen 111). This change is random, and makes evolution a "statistical probability" because of any accidental alterations that could happen to gene frequencies.

The distinctive element of the evolutionary theory conceived by Darwin is the way he viewed species. Darwin considered variation among individuals of a species to be natural. He further argued that variation, far from being problematic, actually provides the explanation for the existence of distinct species. Darwin adopted elements from Malthus’s theory on population growth and stated that only those members of a population that are capable

In the 20th century, with the development of the science of genetics biologists began understanding the mechanics of how traits are passed down to different generations and how they are altered through the discovery of DNA and its major importance. They learned that parts of DNA from each parent are passed down to the offspring. Mutations of DNA, which cause alterations of species, can also occur when traits are being passed down to the offspring. Mutations in DNA can cause the offspring to have difficulties surviving and eventually lead to the extinction of the species. On the other hand, mutation of DNA can affect the offspring positively and change its traits to be stronger and a better survivor in that certain environment which would eventually lead to a growth in population of the certain species. Mutations in DNA can also be neutral and have no effect of the offspring’s traits. This battle with nature and survival through DNA lead to the foundation of the idea of Natural Selection (Alberto 2008).

Biological evolution is the name for the changes in gene frequency in a population of a species from generation to generation. Evolution offers explanation to why species genetically change over years and the diversity of life on Earth. Although it is generally accepted by the scientific community, Charles Darwin’s theory of evolution has been studied and debated for several decades. In 1859, Darwin published On The Origin of Species, which introduced the idea of evolutionary thought which he supported with evidence of one type of evolutionary mechanism, natural selection. Some of the main mechanisms of evolution are natural selection, mutation, and genetic drift. The idea that all life on Earth shares a common ancestor has been around for

Initial ideas of human origins are reflected in the ancient mythologies. Later on, religious versions of human origins appeared. One of the most popular religious theory is creationism. According to it God had created men and everything else in the world. There are two types of creationism, young earth creationism and old earth creationism . Ancient philosophy first proposed ideas of the natural origins of men. Most of its ideas were speculative. It was the product of the ancient philosophers` imagination, but not a result of researching of objective data. Next Charles Darwin offered the Theory of Evolution. Until now this theory is the one of the best substantiated theories in the history of science, supported by evidence from a wide variety of scientific disciplines, including paleontology, geology, genetics and developmental biology. His theory explains how unguided, natural mechanism could structure all the processes in the world, while operating in accordance to the laws of nature . Despite the wealth of evidence from the fossil record, genetics and other fields of science, some people denounce the theory, invoking a higher being as a designer to explain the complex world of living things, especially humans. School boards debate whether the theory of evolution should be taught alongside other ideas, such as creationism. Mainstream scientists see no controversy. Today a lot of people have deep religious beliefs and also accept evolution . There is also a theory of