Kategóriák: Minden - extinction - adaptation - evolution

a omar pachon 5 éve

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Un_animal_sin_importancia

The spread of Homo sapiens from East Africa around 70,000 years ago led to significant interactions with other human species in Eurasia. Two main theories explain these interactions:

Un_animal_sin_importancia

1 CHAPTER AN ANIMAL OF NO SIGNIFICANCE

OUR BROTHERS KEEPERS

The opposite point of view, called "Theory of replacement" tells a very different story: one of incompatibility, repulsion and perhaps even genocide. According to this theory, Sapiens and other humans had different anatomies, and very likely different mating habits and even body odors.
Recent studies indicate that there are traces of DNA from other human species in our DNA, so the theory of crosslinking can not be ruled out altogether, although it had a very limited scope. In all cases, the arrival of Sapiens represented the extinction of the other species, making us think of the predatory nature of our species for different species. YH raises the hypothesis of the meeting between Sapiens and Neanderthals as the first campaign of ethnic cleansing in history.
About 70,000 years ago, Sapiens spread from East Africa to the Arabian Peninsula and from there to Eurasia, which was populated by other human species. There are two opposing theories about what happened: 1) Theory of the reticulation: there was a process of attraction, sex and mixture, and we would be the result of that crossing. 2) Theory of substitution: there was a process of incompatibility, aversion and even genocide, and the Sapiens would have replaced all the other species without crossing.

SKELETONS IN THE CLOSET

It also highlights a time in which we coexisted with other species of our own genus, that is, others, such as Smoke Neanderthalensis, Erectus, Soloensis, Floresiensis, Denisova, Rudolfensis and Ergastes. About 10,000 years ago that Homo Sapiens is alone. It is said that there was a line of direct descent between them. That is, for 2 million years until 10,000 years ago the world was home to several human species.

Presumably, everyone who reads this book is a Homo sapiens, the sapiens (wise) species of the genus Homo (man). - Species: Formed by animals that mate with each other. Our species is SAPIENS - Gender: are formed by species that evolved from a common ancestor. Our gender is HOMO. - Families: Grouping of species originated in a matriarch or Founding patriarch, our family is the GREAT SIMIOS, and says that this has been one of the best kept secrets.

- About 13,500 years ago: Big Bang. His story is the Physics. - About 300,000 years ago: Formation of atoms and molecules. His story is Chemistry - About 3,800 years ago: Complex combinations of molecules form organisms. His story is Biology. - About 70,000 years ago: Organisms of the species Homo Sapiens form cultures. his story is the story.

A RACE OF COOKS

The domestication of fire was key in the ascent to the summit. It began to be used sporadically 800,000 years ago and usually 300,000 years ago. Apart from providing light, heat, protection and creation of clearings in the jungle to facilitate hunting, the main benefit of the fire was that the man began to cook. This allowed to reduce the time dedicated to chewing and the shortening of the intestinal tract, which allowed to allocate more energy to brain development.

THE COST OF THINKING

The author explains how humans always occupied an intermediate place in the food chain, based on the collection and extraction of marrow breaking bones with their stone utensils, and that it was only 400,000 years ago when he began to be able to hunt prey big on a regular basis, which took him 100,000 years ago to the top of the food chain. The jump to the top occurred in such a short time that it did not allow adaptation.
In turn, the upright gait produced in the women the narrowing of the birth canal, which resulted in the natural selection of the earliest births. In comparison with other animals, humans are born prematurely, which contributed to the development of the social abilities of the species and the formation of tribes. In turn, the immaturity of newborns allowed their formation through education.
All human species share a distinctive characteristic: a huge brain compared to the rest of animals, which represents 2-3% of body weight but consumes 25% of body energy when the body is at rest. "The humans diverted energy from the biceps to the neurons." Another distinctive feature is walking on two legs, which allowed the elevated vision and the release of the hands for other tasks.

Three important revolutions shaped the course of history: 1) Cognitive revolution: kick-started about 70,000 years ago. 2) Agricultural Revolution: sped it up about 12,000 years ago. 3) Scientific revolution: which got under way only 500 years ago.

There were humans long before there was history, but their impact on the environment was insignificant like that of any other animal
This book tells the story of how these three revolutions have affected humans and their fellow organisms.