Christians, I know you are interested in the truth. I'm interested in the same thing. This is why I love science, especially evolutionary biology.
"The religious imagination is paltry and petty compared to the awesome reality." -- PZ Myers
Before we face those facts, Christians, you need to understand the tremendous scientific progress of the last decade. Scientists have pretty much figured out everything, and they did not have to invoke supernatural magic to explain any of it. Your god of the gaps has run out of hiding places.
They know how this solar system formed including our planet and our moon. The moon is the most interesting story. When the Earth was still young, less than a half billion years old, a rather big rock about the size of Mars smashed into it. The debris from this mother of all collisions circled our planet eventually forming our moon, and very gradually, a few centimeters every year for four billion years, the distance between the moon and the earth gradually increased to where it is now.
The young earth was also bombarded by countless comets. Our young solar system was a chaotic mess, but partly thanks to our gigantic vacuum cleaner called Jupiter, most of the stuff flying all over the place has already been cleaned up. We still get hit with the occasional huge asteroid. For example about 65 million years ago the dinosaurs who ruled the earth were wiped out by an asteroid that landed near southeastern Mexico. They found the crater under the Gulf of Mexico. (I'm not looking these facts up but it should all be mostly correct, look it up if you're interested.)
With the dinosaurs out of the way our small mammal ancestors who used to be hiding under the ground or at the tops of trees now had the whole planet to themselves and they evolved to fill all the new niches. Eventually only 200 thousand years ago one branch of the tree of life developed into modern human apes, and guess what, Christians, the god you believe in didn't have anything to do with it.
So what does that make us? This is one of the most important facts you Christians will have to face. Obviously we are just animals, just one small twig on the vast tree of life. There's nothing special about us. In our niche a larger brain made our survival possible. Our closest non-human cousins, the chimpanzee apes, evolved just as much as we did, but instead of a larger brain they developed massive strength. The weakest chimp could beat the heck out of the strongest human. And those chimps are not so different from us. They are altruistic and it's interesting that tests have shown their short-term memory is superior to ours.
Also interesting is the fact that the brains of dolphins are equal in size and quality to our brains. They are extremely intelligent animals but we have the advantage of living on land and we have hands.
My point is we are just apes. We are an extremely successful species, but we should never forget where we came from and how we got here. It's wrong to pretend we're special.
What are you going to do with these facts, Christians? Are you going to become mentally disturbed, or are you going to love learning everything you possibly can about the history of life? I suggest to get started you should listen to and/or read the best radio speech ever made about evolution by a biologist at Brown University in Rhode Island at If there's anything that might make Christians understand why denying evolution is a waste of a life, it is this speech by Ken Miller.
Lots of luck Christians. And remember what's important. The truth. Do you want to find it or not?
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The living fossils of brain evolution
The living fossils of brain evolution
May 23, 2012
Enlarge
(Phys.org)
-- In the course of its evolution, the architecture of the mouse brain
may have barely changed. Similar to the tiny ancestors of modern
mammals that lived about 80 million years ago, nerve cells in the mouse
visual cortex are densely packed in a small area of the brain.
However, during the subsequent evolution of larger brains the
architecture of the cerebral cortex was radically restructured. This is
the conclusion of an international team of researchers led by
scientists at the Max Planck Institute for Dynamics and
Self-Organization, the University of Göttingen and the Bernstein Center
Göttingen. The brains of larger mammals, such as humans, however, have
a completely different structure to those of mice. Processes of
self-organisation led to the emergence of modules in which neurons
conjointly are responsible for specific tasks.
Humans are considerably larger than almost all of their ancestors. Our great-great-great-grandparents were on average about 10 centimetres shorter than us. Going further back in time, the difference increases impressively. The ancestors of humans, and modern mammals in general, that lived 80 million years ago all weighed less than 100 grams and were usually only a few centimetres in size. Ecological niches that would have allowed a larger body were occupied by dinosaurs. Only the great extinction that wiped out the dinosaurs 65 million years ago allowed our ancestors a “growth spurt” of historical dimensions. Within just a few million years mammals evolved that were more than 100 times as large as their Mesozoic ancestors.
A well-known international team of scientists led by Max Planck researchers reports in the journal Science that this growth spurt probably led to a fundamental reshaping of neural circuits in the brain. Scientists from the Goethe University in Frankfurt and their international partners hwere also involved in the study. As the researchers discovered, neural circuits in the visual cortex of the brain, corresponding to the smallest details, developed independently in different lineages. Computer simulations and mathematical calculations show that this correspondence reflects basic laws of self-organisation of large-scale neuronal networks. The researchers point towards the existence of “living fossils of brain development”. This refers to species which preserved our ancestors’ neuronal circuits’ architecture until today. Among them, amazingly, is also one of the closest relatives of primates: the mouse.
An essential aspect of human evolution was the enlargement of the brain and especially of the cerebral cortex, whose tasks include conscious perception, decision making, and many memory processes. This brain area in humans – as in many other mammals – is divided into modules in which groups of neurons are interconnected in dense networks and contribute to common tasks, such as the perception of a certain hue. The paper, which has been published in Science, analyses the evolution of what is known as orientation columns, modules of the visual cortex that build the basis of the perception of form.
Hundreds of these modules, which typically have a size of about one millimetre, are located side by side within the visual cortex. The new study shows that this spatial orientation precisely follows geometric rules. Surprisingly, the same laws have evolved independently in separate lineages that led to the development of big brains and even in animals that differ greatly from each other in brain size. The new results thus refute a competing hypothesis that assumes strong dependencies of geometrical properties and brain size. It suggests that during a substantial period of the evolutionary enlargement of the brain only the number of modules increased. The laws of their arrangement, however, remained unchanged.
The authors point out that these laws cannot apply for the entire phylogeny. Wolfgang Keil, first author of the study explains: “In our Mesozoic ancestors, these rules of brain architecture must have reached their limits. Their brains were so tiny that not even a single module would have fitted in the cerebral cortex.” Thus, the researchers consider it to be likely that our ancestors had a fundamentally different architecture of their visual cortex.
In fact, all living mammals that are lighter than 100 grams seem to lack orientation columns completely. In mice, for example, nerve cells that process different tasks in the visual cortex are seemingly randomly mixed. Whether our brain architecture originates from a mixed or an even stranger brain organisation can only be deduced after further investigations, the researchers argue. An important task for future studies will be an investigation of laws that govern small brains. “In fact, there are many dark continents in terms of the architecture of the visual cortex in the different lineages of mammals,” says Fred Wolf, head of the study at the Max Planck Institute for Dynamics and Self-Organization and the Bernstein Center for Computational Neuroscience. The scientists hope that their work will encourage colleagues around the world to help resolve this fundamental mystery of our origins.
Enlarge
Ancestor
(left) and descendant (right). The image shows a reconstruction of the
common ancestor of all living mammals (Hadrocodium wui) from the Early
Jurassic, which has the size of a paper clip. Right, a model of a human
brain. In terms of brain organisation, the mouse (centre) is probably a
“living fossil”. The diagrams to the right show a mixed (right) and a
modular ordered structure of nerve cells in the cortex. Credit: MPIDS
Humans are considerably larger than almost all of their ancestors. Our great-great-great-grandparents were on average about 10 centimetres shorter than us. Going further back in time, the difference increases impressively. The ancestors of humans, and modern mammals in general, that lived 80 million years ago all weighed less than 100 grams and were usually only a few centimetres in size. Ecological niches that would have allowed a larger body were occupied by dinosaurs. Only the great extinction that wiped out the dinosaurs 65 million years ago allowed our ancestors a “growth spurt” of historical dimensions. Within just a few million years mammals evolved that were more than 100 times as large as their Mesozoic ancestors.
A well-known international team of scientists led by Max Planck researchers reports in the journal Science that this growth spurt probably led to a fundamental reshaping of neural circuits in the brain. Scientists from the Goethe University in Frankfurt and their international partners hwere also involved in the study. As the researchers discovered, neural circuits in the visual cortex of the brain, corresponding to the smallest details, developed independently in different lineages. Computer simulations and mathematical calculations show that this correspondence reflects basic laws of self-organisation of large-scale neuronal networks. The researchers point towards the existence of “living fossils of brain development”. This refers to species which preserved our ancestors’ neuronal circuits’ architecture until today. Among them, amazingly, is also one of the closest relatives of primates: the mouse.
An essential aspect of human evolution was the enlargement of the brain and especially of the cerebral cortex, whose tasks include conscious perception, decision making, and many memory processes. This brain area in humans – as in many other mammals – is divided into modules in which groups of neurons are interconnected in dense networks and contribute to common tasks, such as the perception of a certain hue. The paper, which has been published in Science, analyses the evolution of what is known as orientation columns, modules of the visual cortex that build the basis of the perception of form.
Hundreds of these modules, which typically have a size of about one millimetre, are located side by side within the visual cortex. The new study shows that this spatial orientation precisely follows geometric rules. Surprisingly, the same laws have evolved independently in separate lineages that led to the development of big brains and even in animals that differ greatly from each other in brain size. The new results thus refute a competing hypothesis that assumes strong dependencies of geometrical properties and brain size. It suggests that during a substantial period of the evolutionary enlargement of the brain only the number of modules increased. The laws of their arrangement, however, remained unchanged.
The authors point out that these laws cannot apply for the entire phylogeny. Wolfgang Keil, first author of the study explains: “In our Mesozoic ancestors, these rules of brain architecture must have reached their limits. Their brains were so tiny that not even a single module would have fitted in the cerebral cortex.” Thus, the researchers consider it to be likely that our ancestors had a fundamentally different architecture of their visual cortex.
In fact, all living mammals that are lighter than 100 grams seem to lack orientation columns completely. In mice, for example, nerve cells that process different tasks in the visual cortex are seemingly randomly mixed. Whether our brain architecture originates from a mixed or an even stranger brain organisation can only be deduced after further investigations, the researchers argue. An important task for future studies will be an investigation of laws that govern small brains. “In fact, there are many dark continents in terms of the architecture of the visual cortex in the different lineages of mammals,” says Fred Wolf, head of the study at the Max Planck Institute for Dynamics and Self-Organization and the Bernstein Center for Computational Neuroscience. The scientists hope that their work will encourage colleagues around the world to help resolve this fundamental mystery of our origins.
More information: Wolfgang Keil, et al. Response to Comment on “Universality in the Evolution of Orientation Columns in the Visual Cortex.” Science 27 April 2012: Vol. 336 no. 6080 p. 413 DOI: 10.1126/science.1206416
Provided by Max Planck Society
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