PRESENTED BY: SANTIAGO GOMEZ GOMEZ
March 12, 2011
Evolution is a reason for alarm?
The biological evolution (seen as a theory) is the one that by some transformation or changes have been changing us and all the species from the beginning of times, itsuggest that we all come from one single organism and this changes can be done by the following three process. (Mutation, Natural selection and genetic drift)
The Mutation consists on a change in the DNA chain of an organism, so it will produce different proteins from usual ones (there’s were we can see the change). This mutation process can be seen by the process of: Insertions, deletions,amplification and chromosomes translation.
• Insertions: It consists on adding one or more extra nucleotides in to the DNA chain; they use to happen by errors during replication of repeating elements.
• Deletions: It is the opposite process of the insertions; it removes one or more nucleotide from the DNA chain and it also is product of errors during replication of repairing elements.
•Amplification: Also call gene duplication; it makes multiples copies from the chromosomes regions increasing the dosage of the genes located within them.
• Chromosome translation: it interchanges of genetic parts from no homologous chromosomes.
Also the natural selection process is at its name suggest, a natural process in which traits became more or less common, different conditions from the environmentare the ones who are going to make this variations make possible.
“for example; some beetles are green and some are brown. Since the environment can't support unlimited population growth, not all individuals get to reproduce to their full potential. In this example, green beetles tend to get eaten by birds and survive to reproduce less often than brown beetles do. The surviving brown beetles havebrown baby beetles because this trait has a genetic basis. The more advantageous trait, brown coloration, which allows the beetle to have more offspring, becomes more common in the population. If this process continues, eventually, all individuals in the population will be brown.”
(Example took from http://evolution.berkeley.edu/evolibrary/article/evo_25)
Another example is the genetic reply itis similar to the natural selection witch happen when a population experiences a change in the frequency of a given allele, it happens by random it means it isn’t prepare; it is by luck in other words. This differs from natural selection, because allelic frequency is altered based on the fittest genes surviving to reproduce and the weaker genes dying off. Another difference is that, genetic driftoccurs on smaller populations than the natural selection process.
For example: imagine “there are ten red worms and ten white worms with equal chances of surviving to reproduce. A tree falls on the swamp, killing eight worms; six white and two red. Then suppose two white worms and one red worm get sick and die. By chance, there are now seven red worms and only two white worms left”
(exampletook from http://www.wisegeek.com/what-is-genetic-drift.htm)
These are some of the most important researcher who talked about evolution:
Darwin evolution theory’s are based on the Natural selection, that’s what he said on he’s first book (the origin of the species).
He’s bases where; all organisms produce more offspring than the environment can support, there is plenty of intra specificvariability for most of the characters, competition for limited resources leads to the struggle for life (as Darwin ) or existence (as Wallace), will produce offspring with heritable changes, and as a result, new species arise.
Lamarck concluded that the most recent fossils were related to modern organisms. He outlined a theory of biological evolution can be summarized as follows: individuals change...