Login
Traditionally, the Darwinian theory is based on the premise that the entire evolution of humanity has been rising in stages, ie, each step was better than the last and at the peak of this development places the human Current. It is based on the struggle for life, in which people will be less well adapted to become extinct.
Against this view arises contingency theory, advocated by, among others, Richard Leakey. This places the random process of evolution, extinction of a species depends not only on its adaptation to the environment in which he lives but how lucky we are. Thus evolution becomes completely unpredictable.
One of the key factors leading to differentiate ourselves as a family in primates is our method of locomotion, bipedalism. The evolutionary mutation quadrupedal to bipedal walking necessitated extensive remodeling of bone architecture and simian muscle and general proportions of the lower body. Bipedalism is associated with the advantage of the release of the hands in the task of scrolling, but there have been two trends.
Traditionally there is a conception of human evolution gradually ascending the multiregional model proposes that all modern humans are the evolution of different erectus who settled in each area and the common origin is in Africa more than 1 m
The alternative model, which is decanted Richard Leakey, is the Ark of Noah. He argues that Homo sapiens sapiens originated as a single event in a population and geographic isolation from there spread to other areas. It is based on molecular biology studies of human mitochondrial DNA. Mitochondria are human cells that meet a specific and are only transmitted via the mother. In this transmission mutated mitochondria that accumulate in each of the transmissions and are accumulated in the DNA. The greater the similarity in DNA the greater the similarity of evolutionary relatedness.
This way you can set a women's evolution tree that leads to the base of origin. As a result of the study found that all populations had a very similar DNA and therefore had to have a common origin. The variability of African mitochondrial DNA was more varied, which means that our origin in Africa.
Thus mutations are DNA-level changes that generate evolution ..
In biology and genetics, mutation is an alteration or change in the genetic information (genotype) of a living being and that, therefore, will produce a change in the pattern that occurs suddenly and spontaneously, and which can be transmitted or inherit to the offspring. The genetic unit is able to mutate the gene is the unit of hereditary information that is part of the DNA. In multicellular beings, mutations can be inherited only when they affect the reproductive cells.
Biological evolution is a continuous process of transformation of species through changes in successive generations, and that is reflected in the change of allele frequencies in a population.
Charles Darwin, father of the theory of evolution by natural selection. Generally any process known to evolution in time of change.
All evolution is due to a mutation. But not every change is an evolution of the species. In fact the opposite is usually are countless and the diseases they cause.
Cancer is a mutation of the adult cells that fail to fulfill their fundamental role multipicarse and without control.
An extra chromosome to fertilize the egg (in this case the number 21) is the cause of Down syndrome
An error in the copy of chromosome 3 is responsible for achondroplasia / dwarfism
Other mutations may already be present in our genetic code for generations and inherited as recessive genes that may appear every few generations.
Different is the case of inherited diseases such as:
heart problems
deafness
high pressure
diabetes
asthma
various mental illnesses
and a long long etc.
Reason why in all cultures of the world find the incest taboo but because these diseases often occur in the offspring.
A serious evolution instead a healthy dominant gene that prevents such diseases.
If there is no medicine today all people genetically prone to these diseases have died so only those with the healthy gene (or at least resistant) would live and would be talking about an evolution of the species.
Back this gene may be a recent mutation or be present for generations before and could never prove useful.
It is by this that things like X-Men movie is a total farce because first it is impossible in a single generation of mutations as important (and different from family) and I dare say ignorance, but each one such mutant "evolved" should be hundreds of thousands of dead, diseased, and useless for genetic diseases (if not millions)
