Naked Science Forum
General Science => General Science => Topic started by: beem on 06/02/2009 00:37:19
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or because of it?
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What do you mean exactly by diseases?
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In many cases, the terms disease, disorder, morbidity and illness are used interchangeably, In some situations, specific terms are considered preferable.
So says Wiki (http://en.wikipedia.org/wiki/Disease#Terminology) at least.
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arthritis, cystic fibrosis, multiple sclerosis, spinal bifida among others.
Is there evidence that early man also suffered from physical afflictions?
"Survival of the fittest" springs to mind here, but what's the consensus among scientists?
Is there evidence when gene/cell mutations began?
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There is prehistoric evidence for disease among prehistoric humans.
http://en.wikipedia.org/wiki/Prehistoric_medicine
We are animals like any other, and all species are vulnerable to some diseases, so there's no reason to think that none of our ancestors ever developed diseases.
Natural selection tends to select against individuals who are diseased or maladapted to their environment to such an extent that their reproductive success is compromised. This is where "survival of the fittest" comes from.
Mutations occur all the time. Mutation rates can be measured. Where there are genes to be copied, genetic mutations will occasionally arise and many of those will be inherited. We know that mutations have been occurring since the first single-celled organisms evolved over 3.5 billion years ago, because of the amount of genetic diversity and the fact that we can trace the origin of mutations by comparing the genomes of different species.
http://en.wikipedia.org/wiki/Mutation
http://en.wikipedia.org/wiki/Molecular_phylogenetics
Hopefully this is helpful.
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It was indeed.
Thanks for those links.
Among animals, an advantageous gene (such as a new colour trait) that improves camouflage may be passed to offspring, allowing more offspring to survive. Therefore increasing the prevalence of that gene.
Can the same be said for humans? Could it be said that humans, being at the top of the food chain--with fewer risks to survival than animals--bear genes today that would not have been passed along otherwise?
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Whilst new diseases must have evolved over the years, ancient Man must have had them - he's a Johnny come lately, after all and there must have been loads of disease organisms to infect him and his fellow animals. There may be a lot less evidence in ancient remains than there would be from modern corpses because they would often not survive for the disease to show itself - the ones who couldn't run as fast got eaten so, if you were feeling a bit off, with the beginnings of a viral infection, you would be the one who the predator got.
Evolution towards disease resistance must have occured - that's fairly obvious - and this can also have affected other characteristics. But also, it is thought, there is a lot of movement of genes between individuals, carried by microbes. This is, potentially, a very rapid mechanism for evolution. You could imagine being 'infected' with a new, revolutionary, characteristic which would be passed on to your offspring.
The 'family tree' model can no longer strictly apply. Perhaps the 'God Gene' arrived that way?
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But aren't all changes mutations?
Good or bad.
Are mutations increasing?
I just mended the italics for you. Mod
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Yes, all changes to the sequence of DNA are mutations. The Wikipedia links probably explain that.
Mutation rates change depending on the amount of mutagens (mutation-causing factors) in the environment, and the quality of the DNA repair and maintenance mechanisms of the organism's cells.
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Thank you.