Friday 7 March 2008

DNA

The Swiss doctor Friedrich Miescher (1844-1895) discovered DNA in 1869, the same year that Darwin published “The Origin of Species”.
Miescher discovered DNA for first time. DNA is the main component of genetic material in most living beings. The components of DNA are nucleotides, formed by acid, desoxirribose and nitrogenous bases.The substance that Miescher discovered is white, sweet, slightly acid and has phosphorus. He found it in the pus in the bandages and in the salmon sperm.
Its name is nuclein because he found it in the cell nucleus. The discovery improved a lot the development of Molecular Biology Science.

In 1953 Watson and Crick discovered the Double Helix Structure of DNA. Each molecule of DNA is formed by two chains which have got a lot of nucleotides. These chains form a sort of twisted stair called Double Helix.


Thursday 6 March 2008

DISCOVERIES: GENETICS




What: The laws of the heredity ( “Mendel´s Laws” ).

Who: Gregor Johann Mendel.


When: In 1865.
15th of April: is assassinated with a firing in the head the president Abraham Lincoln by the actor John Wilkes Booth.

How: Mendel studied during years, plants of peas of different species and their descendants, and he observed that many characters were transmit of a plant to the following one.
He came to the conclusion that the living creatures transmit their characters to the descendents (this explains the similarity of the children to parents).
Mendel is known like the father of the genetics.

Genetics is the part of Biology that studies the heredity and its variations.
Today, the genetics can be applied to create more resistant organisms to plagues, eradicate diseases, clone creatures choose the sex, fertilization in vitro, etc…

Tuesday 4 March 2008

Theory of evolution

Charles Robert Dawin(12/2/1809-19/4/1882),he was a British biologist that sat down the bases of the modern theory from the evolution when outlining the concept of evolution of the species through a slow process of natural selection.

TRAVEL IN THE BEAGLE(27/12/1831-2/10/1836)
After graduating in Cambridge in 1831, the young Darwin signed up to the 22 years in the recognition ship HMS Beagle like naturalistic without pay, thank you in great measure to the recommendation of Henslow, to undertake a scientific expedition around the world. The expedition lasted five years and it picked up data in the water, geologic and meteorological in South America and other many places.The observations of Darwin took him to develop the theory of the natural selection.

THE THEORY OF THE EVOLUTION DE DARWIN
The observations told him that the life is evolution and that some species originate of others.

The evolutionary theory or darwinismo are summed up in the following points:
1ºThe forms of life are not static but rather they evolve;the species change continually, unite they originate and others of they extinguish.
2ºThe process of the evolution is gradual, slow and continuous, without discontinuous jumps or sudden changes.
3ºThe similar organisms are related and they descend of a common ancestor.All the alive organisms can go back to an only origin common of the life.
4ºThe natural selection is the key, in two phases that he/she explains the whole system.
The first phase is the production of variability: the generation of spontaneous modifications in the individuals.
The second, the selection through the survival in the fight for the life: the individuals better gifted, those that have been born with favorable spontaneous modifications to make in front of the environment will have more possibilities to survive, of reproducing and of leaving descendant with these advantages.

The points 1º and 3º were accepted by most of scientific serious.
The point 2º followed trajectories you give same.
The point 4º have been the most discussed one as much for biologists as for philosophers.

Sunday 2 March 2008

The rabies vaccine


The rabies is a serius illness of the central nervous system. It affects the mammals, including humans. It is caused by a virus which is transmitted through the saliva.

The rabies vaccine is one medicine which is inserted into the organism by injection. It’s used for avoiding and attacking the disease.

The discoverer of the vaccine was Louis Pasteur. He was born on 7th December 1822 in Xura (France). He was interested in chemistry (although in school he wasn’t very brilliant). He was a teacher of chemistry in Strasburg (1847-1853). He was the discoverer of several vaccines, and the rabies was one of them (it was the most important). Pasteur died in 1895, ten years after he discovered the vaccine.


On 4th June 1885, a 9 year old boy, Joseph Meister, was bitten by his dog, which had rabies. His parents took him to Pasteur. If Pasteur didn’t do anything, the boy would die with a lot of pain. Pasteur injected the vaccine during 11 days so as to help the body of the boy to form the necessary defenses. The boy finally survived and Pasteur was the miracle man. It was 123 years ago in Paris (France) and in this year:

· France conquered Madagascar.
· King Alfonso XII died (Spain)

Since 1885 the vaccine of Pasteur has saved many lives. Nowadays if we are bitten by a rabious dog, we don’t die of rabies. Thanks to this discovery thousands of people have survived.