Darwin’s Theory презентация

1882) was an English naturalist. He established that all species of life have descended over time from common ancestors, and proposed the scientific theory that explains that this branching pattern of evolution, resulted from a process that he called natural selection.

book “On the Origin of Species”, overcoming scientific rejection of earlier concepts of transmutation of species. By the 1870s the scientific community and much of the general public had accepted evolution as a fact.

of the modern evolutionary synthesis from the 1930s to the 1950s that a broad consensus developed in which natural selection was the basic mechanism of evolution. 

In modified form, Darwin's scientific discovery is the unifying theory of the life sciences, explaining the diversity of life.

a cartographic consignment of five years, around the coasts of South America. When Darwin was young, he was recommended to Robert Fitzrov, the captain of this ship.

allowed him to study the geological characteristics of continents, islands, and a lot of organisms and fossils. He collected methodically a large amount of samples, unknown to science: this samples, were given to British Museum, and only those samples were an enormous scientific contribution.

conceived his theory of natural selection. Although he discussed his ideas with several naturalists, he needed time for extensive research and his geological work had priority.

He was writing up his theory in 1858 when Alfred Russel Wallace sent him an essay which described the same idea, prompting immediate joint publication of both of their theories.

scientific explanation of diversification in nature. 

In 1871 he examined human evolution and sexual selection in The Descent of Man, and Selection in Relation to Sex, followed by The Expression of the Emotions in Man and Animals.

evidences
Direct Observation
Biogeography
Fossils
Homologous Structures

his interest were the artificial selection. He talked a lot about the intersection of pigeons: in order to obtain a thinner beak or larger wings. In general, the artificial selection, is the selection operated by man. Voluntary (like the intersection between species) or not.

Betularia.

the '800 a lot of factories were born in this territory.

Slowly the white moth was replaced by the black moth.

the white moth, resting on these trees, became targets for the raiders, and because of the contrast it couldn't camouflage. Slowly the darkest moth replaced the clearest one, until the clear ones disappeared. When an animal changes its colour to camouflage because of any change in the environment or because of the humans, we talk about industrial melanism.

same area, there were different types of creatures and species. Biogeography was the weapon to destroy the idea of creationism. But the numerous examples of different species in the same area, were only a support to the evolution theory: every single animal is different, because they have different needs, and different ways of surviving.

Darwin studied a lot of them. He discovered a substantial difference between ancestral creatures and modern ones. Unfortunately, this wasn’t enough, because nothing proved a gradual changing from a primitive form. For this reason Darwin described this evidence as “little remarkable”.

that was shared by every single creature on Earth. The same starting DNA sequence shows us the common origin of the species.

As we can see in the image, different creatures share the same basic structure. This structure was particular of an animal called ancestral tetrapode, or more precisely Silvanerpeton Miripedes.

didn’t explain the origin of the variation that permitted the evolution, but for that we have to wait until the XX century, when Mendel would analyse this matter.