How many humans have lived on Earth?

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The discussion centers on estimating the total number of humans who have lived on Earth, starting from a defined point 1 million years ago. Participants debate the criteria for defining a human and the complexities of calculating population growth rates over time. Estimates vary, with one participant suggesting around 100 billion humans have lived, while others express skepticism about the accuracy of such figures. The conversation also touches on the challenges of using fossil records and archaeological evidence to derive meaningful estimates. Ultimately, the question remains complex and largely speculative, highlighting the difficulties in obtaining precise historical population data.
  • #51
jimmysnyder said:
I wonder if there is a non-sequitur going on. Many fossils are millions of years old so they must have taken millions of years to form.

DaveC426913 said:
Of course, this is all just rationalization. God did all this 6000 years ago...
Bingo!
 
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  • #52
DaveC426913 said:
Of course, this is all just rationalization. God did all this 6000 years ago...
When scientific measurements, such as radiocarbon dating, are made, the Flying Spaghetti Monster "is there changing the results with His Noodly Appendage.
 
  • #53
Here is a report from the Smithsonian/NASA Astrophysics Data System

ADS said:
This study evaluates the accuracy of U/Th dates for young (< a few thousand years old) reef corals, both living and fossil, and explores strategies for refining those dates.

Apparently it does not take millions of years to create a fossil. Dryness isn't necessary either it seems.
 
  • #54
jimmysnyder said:
Here is a report from the Smitsonian/NASA Astrophysics Data System



Apparently it does not take millions of years to create a fossil.
I don;t think that's quite the same thing. Corals are already a framework of mineralized organic material.
 
  • #55
jimmysnyder said:
Apparently it does not take millions of years to create a fossil. Dryness isn't necessary either it seems.
Fossil just means 'preserved remains' (it's latin for dug-up) - the bones-turned-to-rock process is properly called mineralisation.
 
  • #56
mgb_phys said:
Fossil just means 'preserved remains' (it's latin for dug-up) - the bones-turned-to-rock process is properly called mineralisation.
Yes, that was going to be my other comment. When they're talking about corals, I really doubt they're using 'fossil' in the common sense anyway (even if it did mean bones-to-rock).
 
  • #57
DaveC426913 said:
I don;t think that's quite the same thing. Corals are already a framework of mineralized organic material.
Are you saying that the corals were already millions of years old before they died less than 1000 years ago? You have a tenacious hold on this idea that it requires millions of years to create a fossil and that is why I am convinced you can post a citation in support of that idea.
 
  • #58
jimmysnyder said:
Are you saying that the corals were already millions of years old before they died less than 1000 years ago?
What? I never said anything of the sort. They don't need to be millions of years old to be formed of a mineralized framework. They build this while they're alive.

Actually, they build on top of the framework. The living parts of coral are the top few inches formed over a calcified framework of older coral that's been built up over tens of thousands of years. But that's not fossilisation, that's just a calcified remnant structure. Sea cucumbers and sand dollars do a similar thing (just not in giant communal structures). It's basically their skeleton left behind.
 
  • #59
DaveC426913 said:
What? I never said anything of the sort.
If the coral are not millions of years old then fossils don't take millions of years to form. Cite if you will. If not, then your methods are no different than those of a creationist. You believe and so it is true.
 
  • #60
jimmysnyder said:
If the coral are not millions of years old then fossils don't take millions of years to form. Cite if you will. If not, then your methods are no different than those of a creationist. You believe and so it is true.
Jimmy, are you having me on?
 
  • #61
jimmysnyder said:
if the coral are not millions of years old then fossils don't take millions of years to form.
The corals are not fossils.
 
  • #62
Look.

Dinosaurs and other animals have bones that get buried in sediment. Eventually, the bone is replaced with mineral. We are left with an impression of the bone (not the actual bone). This process of mineralisation takes a long time - eons. It is a non-living, chemical-only process. This is what has traditionally been called a "fossil".

Coral, on the other hand, as a part of the its normal life cycle, secretes stuff that forms a calciferous firmament. As generation after generation of coral polyp lives and dies, this framework builds up to a hgue mound. This takes hundreds to thousands of years and is a part fo the corals' life-cycle.

The two are not the same thing.

What I am claming is that they are using the term 'fossil' in the sense that mgb_phys has stated - i.e. it is merely something they've dug up (the buried ancient coral structures). It isn't "mineralized" and isn't millions of years old; it's thousands of years old.
 
  • #63
I am wracking my brains here trying to figure out what your beef is. I'm clutching at straws here so I hope I don't insult you when I ask:


You do know that this:
DaveC426913 said:
Of course, this is all just rationalization. God did all this 6000 years ago...
was a joke, right?
 
  • #64
DaveC426913 said:
I am wracking my brains here trying to figure out what your beef is.
My beef is that I don't believe that it requires millions of years to mineralize a fossil. I provided a website that speaks of coral fossils that are less than 1000 years old. It is a Smithsonian/Nasa collaboration, not some crank site. If you think the coral was not millions of years old when it died, then fossilazation did not take millions of years no matter how you slice it. If, on the other hand you think the coral was millions of years old when it died and became fossilized less than 1000 years ago, then what makes you think so. I am willing to change my mind on this. But you have provided me with no reason to do so other than asking me to bow to your authority. Cite something. I repeat, you are very sure that you are right. There must be some reason that you are so sure. I am not sure of anything and that is why I beg you to help me out here. It seems to me that something must surely stabilize the remains of a living thing before millions of years pass.
 
  • #65
Jimmy, this is a misunderstanding of semantics.

I'll say it again, what they're calling "fossils" are not "bones that have been mineralized". What they're calling "fossils" are dead coral mounds that they've excavated.

As mgb points out, fossil can simply mean "stuff dug up".

Look up the lifecycle of coral polyps and the creation coral reefs to understand what I'm saying because I don't think you know what they are.

Perhaps a little bit of the onus should fall on you. You've practically demanded an education in paleontology, and I think I've been pretty accommodating. I'm not asking you to bow to my authority, I'm asking you to look up "fossil" and creation of "coral reef" and see how different they are.
 
  • #66
Perhaps it would be better to go full over to mgb's definitions and say "it takes millions of years to mineralize buried bones".

Since fossils are merely "dug up stuff" then you could say it takes a very short time for something to "become a fossil" (i.e. just long enough to bury it) - even if it would take eons to "mineralize" it.

Does that make it more palatable?
 
  • #67
Okay, stop arguing guys! I always thought that fossils were dinosaur bones, how else would we get our oil from other than from bones of dead beasts that died long ago.
 
  • #68
Zdenka said:
Okay, stop arguing guys! I always thought that fossils were dinosaur bones, how else would we get our oil from other than from bones of dead beasts that died long ago.
From cars that gave up their oil so that other ICE's might live?

When I was running junkers in the 60's and 70's, I sometimes bought Fox reprocessed motor oil in gallon tins. OK, I needed to get to work and couldn't afford ring-jobs, etc. I run some pretty clean rigs, now.
 
  • #69
DaveC426913 said:
I'm asking you to look up "fossil" and creation of "coral reef" and see how different they are.
I have been looking up fossil for hours over the past two days and I can't find a site that says how long it takes to form a fossil. For the third time, what makes you so sure when I am so perplexed? There is no onus on me to show why I'm not sure, the onus is on you to show why you are.
 
  • #70
jimmysnyder said:
I have been looking up fossil for hours over the past two days and I can't find a site that says how long it takes to form a fossil. For the third time, what makes you so sure when I am so perplexed? There is no onus on me to show why I'm not sure, the onus is on you to show why you are.
OK, I think we've been crossing our wires.

I've been perplexed because you seem to have been confusing normal coral reef building with (what I am now finding is technically known as) permineralization. That seems to have been missing the point from my PoV.

(I will frorm this point on, use the terms fossil and permineralisation as per mgb's suggestion. Fossils are things dug up. Permineralization is what happens when bones are replaced with minerals.)

However, I must concede, I do not actually know how long it takes for buried bones to be replaced by mineral. You are right, it is always something I've "just known" and, in this case I have been oversimplifying the issue because this discussion is really (supposed to have been) about humans. And fossilization or permineralisation is just not applicable.

I too cannot find a reference that states how long this process of permineralization takes.
 
  • #71
Found some!

"If mineral-rich water percolates down through the sediments, the fossil formation process has an even better chance of preserving our ancient animal. Some of the minerals stick to the particles of sediment, effectively gluing them together into a solid mass. These minerals make an impact on our original trilobite as well. Over the course of millions of years they dissolve away the outer shell, sometimes replacing the molecules of exoskeleton with molecules of calcite or other minerals. In time the entire shell is replaced leaving rock in the exact shape of the trilobite. That is fossil formation at work."
http://www.fossils-facts-and-finds.com/fossil_formation.html

"Over millions of years the original shell is completely replaced by the minerals and what remains is a rock-like copy of the original shell."
http://www.discoveringfossils.co.uk/whatisafossil.htm

Over millions of years, the remains are completely replaced by the minerals, leaving a rock-like copy.
http://www.newworldencyclopedia.org/entry/Fossil
 
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  • #72
DaveC426913 said:
Found some!
Thank you. This answers my question where did you get the idea.
 
  • #73
Dave, you have been very patient and professional during this exchange. I must commend your efforts.
 
  • #74
I agree with Chi, Dave you are da man! Now, I understand when they dig up a 'dinosaur bone' it's actually not their bones but the fossilized casing around it. Cool stuff! :))
 
  • #75
I bet it is none Earth tastes like sh---.
 
  • #76
Zdenka said:
I agree with Chi, Dave you are da man! Now, I understand when they dig up a 'dinosaur bone' it's actually not their bones but the fossilized casing around it. Cool stuff! :))
Actually, it's not a "casing around it", it's within the space where the fossil was. So it takes on the exact dimensions, sometimes down to the finest details. It is analagous to a "lost wax" molding technique.
 
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