Evolution - Reality and Misconceptions
Discussion
E34-3.2 said:
Earth was covered of water for Years before the continents formed.
Even were that the case, that is not what you said.Can you genuinely not manage to debate honestly? Is there a reason that you suggest one thing then argue another? It doesn’t make you look clever, it actually makes you look really ignorant.
E34-3.2 said:
https://news.nationalgeographic.com/news/2014/10/1...
https://www.google.fr/amp/s/amp.ibtimes.co.in/eart...
https://www.google.fr/amp/s/www.newscientist.com/a...
Again, utter dishonesty. Why? Those articles mention the Earth hundreds of millions of years after it formed.https://www.google.fr/amp/s/amp.ibtimes.co.in/eart...
https://www.google.fr/amp/s/www.newscientist.com/a...
Do you honestly not understand the links that you post?
You must be a troll, well done, you got me, you’ll not be responded to again.
James_B said:
Even were that the case, that is not what you said.
Can you genuinely not manage to debate honestly? Is there a reason that you suggest one thing then argue another? It doesn’t make you look clever, it actually makes you look really ignorant.
Sorry, not sure what you are talking about? Maybe I haven't employed the right sentence? I guess English is you first language... not mine. Can you genuinely not manage to debate honestly? Is there a reason that you suggest one thing then argue another? It doesn’t make you look clever, it actually makes you look really ignorant.
E34-3.2 said:
Moonhawk said:
Based on the distinct aroma of 'creationism' i'm getting off their posts, I suspect they are trying to conflate this one study with the biblical flood story.
Flood story in the Bible came after earth was populated, no before. Eric Mc said:
So you agree, the earth existed for quite some time (millions of years) before any water existed (indeed, could exist) on its surface.
Yes, know I understand why the other poster thought I wasn't honest. I said it started as a ball of water but my wording is completely wrong! I just wanted to say that before we developed (us human), looks like earth was covered of water. So basically not the very beginning. Sorry, my vocabulary in English is not making things easy. Modern humans arrived on the scene very recently i.e. around 1 million years ago at most, so the state of the earth when homo sapiens arrived has nothing to do with how earth has been for most of its history - which goes back 4.5 billion years.
There is no evidence whatsoever that the earth was, at one time, an 100% ocean world.
There is a theory that there may have been at least one geological period where the earth was completely encased in ice (the "snowball earth" theory) which might have happened around the Permian Period about 300 million years ago to 250 million years ago. There is some evidence for this bit it is a bit sketchy and not something that all paeleogeoligists agree on.
There was a "Permian Extinction" event at the end of the Permian Period which was actually a lot more dramatic and devastating than the extinction event at the end of the Cretaceous. The further back in time you go, the more sketchy the geological record and teh fosil record becomes so the harder it is to read what the rocks tell us.
It is highly likely that Continental Drift i.e. the moving of continental plates, began pretty early on in earth's history, not long after the crust solidified.
There is no evidence whatsoever that the earth was, at one time, an 100% ocean world.
There is a theory that there may have been at least one geological period where the earth was completely encased in ice (the "snowball earth" theory) which might have happened around the Permian Period about 300 million years ago to 250 million years ago. There is some evidence for this bit it is a bit sketchy and not something that all paeleogeoligists agree on.
There was a "Permian Extinction" event at the end of the Permian Period which was actually a lot more dramatic and devastating than the extinction event at the end of the Cretaceous. The further back in time you go, the more sketchy the geological record and teh fosil record becomes so the harder it is to read what the rocks tell us.
It is highly likely that Continental Drift i.e. the moving of continental plates, began pretty early on in earth's history, not long after the crust solidified.
Eric Mc said:
Modern humans arrived on the scene very recently i.e. around 1 million years ago at most, so the state of the earth when homo sapiens arrived has nothing to do with how earth has been for most of its history - which goes back 4.5 billion years.
There is no evidence whatsoever that the earth was, at one time, an 100% ocean world.
There is a theory that there may have been at least one geological period where the earth was completely encased in ice (the "snowball earth" theory) which might have happened around the Permian Period about 300 million years ago to 250 million years ago. There is some evidence for this bit it is a bit sketchy and not something that all paeleogeoligists agree on.
There was a "Permian Extinction" event at the end of the Permian Period which was actually a lot more dramatic and devastating than the extinction event at the end of the Cretaceous. The further back in time you go, the more sketchy the geological record and teh fosil record becomes so the harder it is to read what the rocks tell us.
It is highly likely that Continental Drift i.e. the moving of continental plates, began pretty early on in earth's history, not long after the crust solidified.
I didn't even realise that we had 2 huge extinction periods! I must have always thought of the cretaceous period (is that the one that most of people think?) Huge difference in what species used to leave?There is no evidence whatsoever that the earth was, at one time, an 100% ocean world.
There is a theory that there may have been at least one geological period where the earth was completely encased in ice (the "snowball earth" theory) which might have happened around the Permian Period about 300 million years ago to 250 million years ago. There is some evidence for this bit it is a bit sketchy and not something that all paeleogeoligists agree on.
There was a "Permian Extinction" event at the end of the Permian Period which was actually a lot more dramatic and devastating than the extinction event at the end of the Cretaceous. The further back in time you go, the more sketchy the geological record and teh fosil record becomes so the harder it is to read what the rocks tell us.
It is highly likely that Continental Drift i.e. the moving of continental plates, began pretty early on in earth's history, not long after the crust solidified.
There is evidence that there may have been four or five mass extinctions - not just two.
As I said, the problem is that the geological and fossil record becomes harder to read the further back in time you go.
The earth is an extremely dynamic planet from a geological point of view. Convection currents in the mantle cause the mantle to circulate over time and this circulation does two main things - it creates new sea floor (sea floor spreading) and pushes the continental plates about. The plates slide around and crash into each other, creating mountains as they do, and the sea floor dives under the continental margins, where it decscends as part of the convection process, heats up and melts. This process destroys a lot of older rock and any fossil records that may be preserved there.
There are only a few known locations on earth where rocks older than about 3 billion years can be found - usually in the centre of large land masses such as North America, Australia and Africa. The fossil evidence for the oldest known life forms known to have evolved on earth are usually found in these locations.
As I said, the problem is that the geological and fossil record becomes harder to read the further back in time you go.
The earth is an extremely dynamic planet from a geological point of view. Convection currents in the mantle cause the mantle to circulate over time and this circulation does two main things - it creates new sea floor (sea floor spreading) and pushes the continental plates about. The plates slide around and crash into each other, creating mountains as they do, and the sea floor dives under the continental margins, where it decscends as part of the convection process, heats up and melts. This process destroys a lot of older rock and any fossil records that may be preserved there.
There are only a few known locations on earth where rocks older than about 3 billion years can be found - usually in the centre of large land masses such as North America, Australia and Africa. The fossil evidence for the oldest known life forms known to have evolved on earth are usually found in these locations.
4x4Tyke said:
Agreed, but like everything evolutionary, the picture is far more nuanced and complex.
We tend to be long sighted in youth and become progressive short sighted as we age. It is feasible that evolution selected for that (no idea if it's actually been studied), or it might not be a sufficient disadvantage to be deselected. We do know that women generally have a shallower depth of focus than men. Not a survival problem and perhaps an advantage given what we know of ancient gender roles, with women tending to be nurturers & gathers vs an ancient men tending to be hunters.
Evolutionary survival of the fittest resulted in that change? Plausible. Evolution might have selected that, or not found it a problem with fitness. The long sighted young being better equipped to hunt vs older crafters being better able to perform close up intricate work like napping spear tips. Yes it is a bit chicken and egg, but does seem to show the attribute of a positive feedback loop we see throughout evolution.
We do know that night hunting animals generally have more rods than cones, because rods are better at detecting outlines and movement in low light. While day hunters have better colour detection. Evolution is going to find a balance.
It is plausible that things like colour blindness are the same, perhaps somebody can answer the question; is colour blindness really a matter of a different advantage vs a disadvantage. It might be similar to cystic fibrosis or sickle cell.
Degenerative things like cataracts are probably a case of ancient ancestors never really living long enough for a predisposition to that to exert a strong selective pressure, compared to everything else.
Changes/deterioration in sight generally happens after offspring are able to look after themselves so that is not really going to be part of selection, however poor eyesight in youth may well be why the above is the case.We tend to be long sighted in youth and become progressive short sighted as we age. It is feasible that evolution selected for that (no idea if it's actually been studied), or it might not be a sufficient disadvantage to be deselected. We do know that women generally have a shallower depth of focus than men. Not a survival problem and perhaps an advantage given what we know of ancient gender roles, with women tending to be nurturers & gathers vs an ancient men tending to be hunters.
Evolutionary survival of the fittest resulted in that change? Plausible. Evolution might have selected that, or not found it a problem with fitness. The long sighted young being better equipped to hunt vs older crafters being better able to perform close up intricate work like napping spear tips. Yes it is a bit chicken and egg, but does seem to show the attribute of a positive feedback loop we see throughout evolution.
We do know that night hunting animals generally have more rods than cones, because rods are better at detecting outlines and movement in low light. While day hunters have better colour detection. Evolution is going to find a balance.
It is plausible that things like colour blindness are the same, perhaps somebody can answer the question; is colour blindness really a matter of a different advantage vs a disadvantage. It might be similar to cystic fibrosis or sickle cell.
Degenerative things like cataracts are probably a case of ancient ancestors never really living long enough for a predisposition to that to exert a strong selective pressure, compared to everything else.
Edited by 4x4Tyke on Wednesday 5th September 12:48
You do not start out long sighted and get short sighted if you have healthy vision, you start out with a wide dynamic focal range and it becomes compromised at one or both extremes due to weakening of the eye muscles and stiffening of the lens. This also affects accomodation response, i.e. it takes longer to change focus from one extreme to another. Your lenses also darken with age, then there is the onset of cateracts and damage from UV etc.
TL:DR Eyes have evolved to last as long as they need to in order to replicate the genes.
I am not an evolutionary biologist/geneticist, background is physics/maths/astronomy/electronics so this is just my opinion thoughts as someone with an interest over the last 30 - 40 years.
Edited by Toltec on Thursday 6th September 12:36
Alex said:
AshVX220 said:
Although I don't know if there's evidence of infertility being passed to the next generation.
Infertility is hereditary. If your parents didn't have kids, there's a good chance you won't have any.
I'll get me coat...
I do now recall that when I went through IVF the Doc said that if successful the infertility shouldn't be passed to any children.
Interesting thread.
Someone posted a few pages back what was one taught on evolution; answer for me not a lot. Did the three sciences at school for "O" and "A" level and subsequently went on to do BSc in Applied Biology (physiology & pharmacology).
The only time I remember being taught anything about evolution was A level biology field trip, something about some sand dwelling invertebrate (possibly an insect, 30 odd years ago, can't recall). The main thing in that was driving home the difference between evolution and adaptation. Basically evolution taking thousands, or even millions of generations, whereas adaptation occurs rapidly, often intra-generational, but usually in no more than a couple of generations.
To me evolution taking time (as measured in hours, days, years etc...) seems inherently the incorrect way to measure it as all living things have differing reproduction rates. Strikes me it is better measured in "N"s of generations.
My example being antibiotic resistance, which is evolution in those bacteria, and demonstrates selection of the genes responsible for conferring resistance in "only" 50 or 60 years, but what must be many millions of generations for those bacteria.
Someone posted a few pages back what was one taught on evolution; answer for me not a lot. Did the three sciences at school for "O" and "A" level and subsequently went on to do BSc in Applied Biology (physiology & pharmacology).
The only time I remember being taught anything about evolution was A level biology field trip, something about some sand dwelling invertebrate (possibly an insect, 30 odd years ago, can't recall). The main thing in that was driving home the difference between evolution and adaptation. Basically evolution taking thousands, or even millions of generations, whereas adaptation occurs rapidly, often intra-generational, but usually in no more than a couple of generations.
To me evolution taking time (as measured in hours, days, years etc...) seems inherently the incorrect way to measure it as all living things have differing reproduction rates. Strikes me it is better measured in "N"s of generations.
My example being antibiotic resistance, which is evolution in those bacteria, and demonstrates selection of the genes responsible for conferring resistance in "only" 50 or 60 years, but what must be many millions of generations for those bacteria.
Toltec said:
Changes/deterioration in sight generally happens after offspring are able to look after themselves so that is not really going to be part of selection, however poor eyesight in youth may well be why the above is the case.
However we are a social species, so if parents survive longer through better eyesight, that is going to enhance the survival chances of even their adult offspring, even if only slightly.The rest makes some good points.
Eric Mc said:
There is evidence that there may have been four or five mass extinctions - not just two.
As I said, the problem is that the geological and fossil record becomes harder to read the further back in time you go.
The earth is an extremely dynamic planet from a geological point of view. Convection currents in the mantle cause the mantle to circulate over time and this circulation does two main things - it creates new sea floor (sea floor spreading) and pushes the continental plates about. The plates slide around and crash into each other, creating mountains as they do, and the sea floor dives under the continental margins, where it decscends as part of the convection process, heats up and melts. This process destroys a lot of older rock and any fossil records that may be preserved there.
There are only a few known locations on earth where rocks older than about 3 billion years can be found - usually in the centre of large land masses such as North America, Australia and Africa. The fossil evidence for the oldest known life forms known to have evolved on earth are usually found in these locations.
Had a chance to read the thread now. I like it As I said, the problem is that the geological and fossil record becomes harder to read the further back in time you go.
The earth is an extremely dynamic planet from a geological point of view. Convection currents in the mantle cause the mantle to circulate over time and this circulation does two main things - it creates new sea floor (sea floor spreading) and pushes the continental plates about. The plates slide around and crash into each other, creating mountains as they do, and the sea floor dives under the continental margins, where it decscends as part of the convection process, heats up and melts. This process destroys a lot of older rock and any fossil records that may be preserved there.
There are only a few known locations on earth where rocks older than about 3 billion years can be found - usually in the centre of large land masses such as North America, Australia and Africa. The fossil evidence for the oldest known life forms known to have evolved on earth are usually found in these locations.
Picking up on an earlier point regarding dogs and breeding, having subspecies of domesticated animals is not really evolution as per se, it's the actions of humans creating a narrow genetic base. Sheep and cows for instance have been bred so specifically, they now have w
ky legs.I got in to a bit of a dispute with the alpaca club of GB some years back after I personally valued a "prize-winning" alpaca with a £40k price tag as being worth as much as a fart. I was met with the 'oh you don't know what you're talking about' attitude from some snotty woman who knew everything.
The thing was, alpacas have been bred to have shorter noses, as it's deemed truer to natural form. There's no gene for short noses though. It's a single gene that makes things grow. Breed an animal to have ever shorter noses, and all of a sudden that gene turns off. The same gene forces the development of the cardiac septum, pulmonary septum, nasal septum and any other septum in the body. Naturally, the alpaca club thought they knew better and about 5 years ago a huge glut of alpacas were being born that had deviated cardiac septums. The crias wouldn't stand, failed to thrive and died.
Anyhoo.... the planetary nebulus. One of the first assignments I give my students is about aliens. It gets them thinking about how life can evolve in different mediums. It's because as a sprout I saw an X files show where some guy had a silicon based fungus growing in his lungs and it left a load of sand; the purpose of the assignment is to explore the armchair trekkies view that a silicon based life form cannot exist as we as carbon based produce CO2 therefore a silicon based life form would produce SiO2 and why this assumption is fundamentally wrong; explore and rationalise how life could develop elsewhere in the universe and what form it might take. For example, there'll be life on mars if there's sulphur in the atmosphere, little green men CAN exist but would die on earth and so on.
When earth formed, it was a cloud of dust and gas. Very cold (ok, cold is the wrong word, how can anything in a vacuum of space be hot or cold?) It didn't drop out of God's oven, all hot, boiling and volcanic. The earth didn't cool down, but gravity pulled it all together, and in the PV=nRT phase, as gravity pulls everything towards the centre, it heats up. The hot core throws out eddy's of matter, like a giant lava lamp. All the rocks, minerals, water, ammonia and hydrocarbons (crude oil - if it takes millions of years to create it from insects, where did the tar come from to trap dinosaurs, if the insects needed to form the hydrocarbon hadn't evolved?) swirl around within the planetary nebulus. The earth is akin to a giant lava lamp.
(Slightly o/t but I have a theory that Jupiter does have a solid core, and a liquid layer on top - but as it's all gas, the temperature and pressure would make it uninhabitable - but it would be due to the pressure and temperature created as gravity pulls the gas inwards source but we don't actually know the answer...)
One of those fossil-less areas is the Malvern Hills, big lumps of granite formed when the UK was off the coast of Africa, and before life existed on earth. There's loads of fossils in the sandstone, marls and limestone bits but not the granite, or the shales on the west side. There's also a lot of gold, and I happen to know a few areas where I've scooped a few bags of sediment and panned for the gold (but I'm not saying where, but believe me, it's not much gold, enough to turn 5 kilo's of silt in to a glittery 20 cc of concentrate in a test tube)
Organisms are quite adept at retaining DNA they don't need. Pile up all your post from your life, and it'll have bank statements, mortgage statements, bills, receipts, work stuff, postcards etc. From all your post, I can determine who you are. But there's more junk mail than decent mail.
It's the same with DNA. Yes, we have 46 chromosomes. A life time of mail. It has an awful lot of junk in there, too.
If we're this evolved, with 46 chromosomes, I want you all to imagine how "evolved" something is with, say, 80 chromosomes?
If a human is formed from 46 chromosomes, then what on earth do you get with 1260 chromosomes? Some giant mutant that communicates with brain waves and shoots lasers from its eyes?
Not quite.. A fern does, though
If I don't get my lawnmower back on Friday I'll have more time to contribute to the thread, unfortunately a good friend is going through a very rough time, hence my tardiness on this thread and the delay in adding new pics to my eggs thread (spoiler - the chicks are 5 weeks old now and 12-18 inches high)
Gassing Station | Science! | Top of Page | What's New | My Stuff