Hi Elizabeth , I have a question regarding the Most recent common ancestor , I have heard profesor Dawkins say that we all humans are descendent of a single individual who lived several thousand years ago.
Does this apply to any species ?
So for example , do all dogs come from a single wolf who happen to get close to some leftover from a group of humans ? or , do all bears are descendant of a single individual ?
And when they say the origin of life , are they talking about a single event in wich a single molecule began to self replicate ? or more like many events involving many steps in wich molecules started to replicate.
I have a question regarding the Most recent common ancestor , I have heard profesor Dawkins say that we all humans are descendent of a single individual who lived several thousand years ago.
We really aren't sure this is true. There is no point in time where anyone can say that this or that early hominid was the beginning of humanity, and on the direct line to Homo sapiens. Dawkins was perhaps referring to mitochondrial Eve..... a tracing back thru the female line of women as far as the DNA will take us, but as for a single person? No. He maybe is referring to Lucy.... a skeleton found several decades ago, that showed a female, walking upright. But since then there as been found Ardi...google that one.
Does this apply to any species ? Doubtful it applies to any.
So for example , do all dogs come from a single wolf who happen to get close to some leftover from a group of humans ?
Latest research on dogs indicates that early humans did not try to capture a wolf puppy, and tame it. We know that modern wolf puppies are just not trainable.
What is believed now is that those adult wolves who stuck around the camp fire, and got fed, stayed, and perhaps some of the puppies they had stayed as well.... those not interested left. So, no single wolf was the beginning. You might Google some work done by a Russian.... in 40 generations, by breeding only the tamest of tame foxes, he got dogs.... dogs that were receptive to humans, wanted to be petted wagged their tails etc., and in the process got white on the body and faces. (Just as an aside, you will notice no wild Asian horse, has any body white or blaze. When an animal species is selected for tameness, and bred for tameness, it as well acquires white on its face, legs and chest..... interesting.)
Bears as well are not descended from any individual. What happens to any species, is that when it becomes isolated, it evolves on a new track leaving its ancestry and going off on a new path, and ultimately into becoming a new species, incapable of breeding with the old ancestor.
And when they say the origin of life, are they talking about a single event in wich a single molecule began to self replicate ? or more like many events involving many steps in wich molecules started to replicate.
No one is really sure how life on Earth began....there are lots of theories.
I rather like this one....
We have not only plausible chemical mechanisms by which this might be conceivable, but we also are homing in closer and closer every day to specific pathways that might have allowed bio-molecules including RNA to arise naturally. Interestingly, the coming together of RNA, and then the falling apart into halves, then each side paring up with a like molecule, needed to happen only once.... and with billions and billion of years, and billions and billion of molecules, it was a certainty that this would indeed happen.
And with that life was off and running....Moreover, Darwinian evolution, based on natural selection, provides a compellingly accurate picture of how complex life emerged on this planet following whatever specific chemistry produced the FIRST faithfully self-replicating cells or cell parts, with a metabolism that captured energy from their environment (As good a definition of life as about anyone can come up with).
Just as Darwin, removed the need for divine intervention in evolution of the modern world, teeming with diverse life throughout the planet, our current understanding of the universe, its past, and its future make it more plausible that "something" can arise out of about nothing without the need of any divine guidance.
Because of the observational and related theoretical difficulties associated with working out the details, I expect we may never achieve more than plausibility in this regard. But plausibility itself, in my view, is a tremendous step forward as we continue to marshal the courage to live meaningful lives in a universe that likely came into existence, and may fade out of existence without purpose, and certainly with out us as its center.
Humans are a speck, on a speck we call earth, within a bit larger a speck called our solar system, in a tiny corner of the Milky Way galaxy, which itself is just a spec. In 1925 we thought that our galaxy was the entire universe. Now, with all sorts of equipment, we can see 100 billion galaxies !!!!!!! So, planet earth is pretty insignificant, isn't it?
Helpful? Write back if you need clarification.