QUOTE(Mr Walker @ Aug 11 2006, 01:40 AM) [snapback]1303225[/snapback]
As I was writing my first entry, I realised that someone could look at the time scales and say "hey there is plenty of time for another sentient species to evolve. It only took us 10 million years, that leaves 80 million to play around with, since the dinosaurs.
The trouble is that our own species evolutionary process is quite tightly tied in and proven (if you accept the theory of evolution at all) with the evolution of animals, from the dinosaurs to modern man. You would have to go back to to an unknown time before the dinosaurs and create a whole new evolutionary process to get to a different result. And it is in this time frame that you just run out of time. There is really only time for it all to have happened once.
No, there's plenty of time. Looking at the correlated history of earth, a graphical representation, it's obvious how easiy it would be for another type of sentient life to evolve during the history of life on earth. First there's Bacteria and Prokaryotes, which showed up around 3.5 billion years ago. Then comes Archaea at 2.8 billion years ago, Protoctista and Eukaryotes at 2.2 billion years, Plantae at 1.6 billion years, and Fungi at 1.4 billion years.
Now, assuming sentient life didn't arise from those other kingdoms (bacteria and archaea aren't really kingdoms but worthy of note separately), which is entirely possible, we finally have Animalia at 800 million years. Within the animal kingdom are Cordata arriving 510 million years ago, Amphibia 360 million years ago, Amniota and Reptilia 340 million years ago, synapsids 300 million years ago, and Mammalia 240 million years ago (and Aves 210 million years ago). Now, you can say that all leads up to humans, from Eukaryotes onward (with a few deviations that don't really fit) and that it doesn't leave room for anything else to evolve, but that's failing to take some very important events into account. Events that, without them, we most likely wouldn't have existed.
Extinction.
Everyone knows about the K-T impact, which wiped out the dinosaurs in the Cretaceous, but there has been a lot more over the history of life on earth. Especially the Permian extinction 250 million years ago, which makes the end of the dinosaurs look like a slight cold. Not all of these were major, some affected only one kingdom, phylum, class, etc. I list each major phylum or class as well and indicate where I can, if an entire group was wiped out. Just remember, we're talking about entire species and sometimes even entire groups going extinct. It's like wiping out all the housecats or even every related cat on the planet. Losing all the placodermi might not seem big, but it really is. Starting from the bottom up, bolded means major event:
520 million years ago - Cambrian - 1 phylum in 1 kingdom affected (Animalia)
505 million years ago - Cambrian - 2 phylums in 1 kingdom affected (Animalia)
440 million years ago - Ordovician/Silurian - 7 phylums in 1 kingdom (Animalia)
365 million years ago - Devonian - 5 phylums (1 class hit hard) in 1 kingdom affected (Animalia)
360 million years ago - Carboniferous (Mississippian) - 3 phylums (1 class hit hard) in 1 kingdom (Animalia)
250 million years ago- - Permian/Triassic - Protoctista, Plant, and Animal Kingdoms majorly affected. In Animal Kingdom, 13 Phylums affected. Entire Amphibian class zapped. All non-chordate animals heavily affected. Trilobites, acanthodii, and placodermi (each a class) is entirely wiped out along with many many others. Synapsids go extinct 10 million years later, giving rise to mammals.
214 million years ago - Triassic - 5 phylums in 2 kingdoms affected (Protoctista, Animalia)
205 million years ago - Triassic/Jurassic - 3 phylums in 1 kingdom affected (Animalia).
180-175 million years ago - Jurassic - Reptiles get hit in 3 major subclasses
147 million years ago - Jurassic/Cretaceous - 2 phylums in animal kingdom affected. Mostly reptilia
95 million years ago - Cretaceous - End of the Spinosauridae
65 million years ago - Cretaceous/Paleogene - 5 phylums in 3 kingdoms affected (Protoctista, Plantae, Animalia). Dinosaurs wiped out. Many plants wiped out. Reptilia (dinosaurs) hurt the most.
35 million years ago - Paleogene - 2 phylums in 2 kingdoms affected (Protoctista, Animalia). Mammals take heavy hit.
2.5 million years ago - Neogene/Quaternary - Protoctista zapped
And those are just the extinction
events. That doesn't include others that went extinct on their own, as far as we can tell.
The point of this long, and probably boring, discussion is that with all the intense activity going on, we absolutely
cannot say for sure that there was never another intelligent species on the planet. People make the mistake of thinking any intelligent species will be like us, humanoid, with the same structures and whatnot. That is a mistake. There is no rule that says intelligent life HAS to be similar to us. That's an arrogant assumption for one. For all we know, jellyfish could have been intelligent, but because they are soft-bodied organisms and not well preserved in the fossil record (an understatement if there ever was one), we would have no record of it. As I said before, the fossil record that we have is very very tiny. We can't even begin to say we know what all the life was like on earth in the past because we don't know what all is there.
Look at it this way. Between my fiance and I, we have almost 300 DVDs. Think of that as the history of life on earth. In the process of uncovering my DVD shelf, you find Stargate, Jurassic Park, Red Dwarf, Hellboy, Subway, Transformers, Metropolis, Haxan, 2001, Journey to the Center of Time, and Tobor the Great. That represents what we have uncovered in the fossil record. From looking at that, you would assume that we have a strong affinity for science fiction and in fact, would define us as being primarily science fiction enthusiasts. However, what hasn't been discovered yet is lots of John Wayne movies, documentaries, comedy routines and television shows, dramas like The AViator and The 25th Hour, and cheesy action movies. Even if the John Wayne movies (11) make up less than 4% of the entire collection, that doesn't mean they don't exist or could never exist. They just haven't been found yet.
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There is absolutely no accepted evidence at all that some branch of evolution broke off between the dinosaurs and the present to create a different sentient species.
I didn't realize people were assuming that something broke off from the dinosaurs. Dinosauria is only an infraclass of the class Reptilia, which is a small part of phylum Chordata, which is only a small part of kingdom Animalia. It's not like there were dinosaurs and then there were mammals. There's the invertebrates to think of, at the very least. Amphibians, plants, fungi, etc.
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Yes, isolated pockets of such people may have lived and had their existence wiped out by geologic change, but to reach an advanced technology the population would have been widespread and radically changing its own environment. this would have left evidence discoverable. even now.
Like I've said, it could be there but we haven't found it yet. Antarctica used to be tropical from fossils we've found, but we haven't even begun to scratch the surface of the organisms that used to live there because very little of the continent is reachable. Same with the northern regions.
Also, that's assuming there would be a sentient species that was even like us. Like I said, to assume that is arrogant. And for all we know, they could have been smarter than us and not run rampant across the globe. Of course, even thinking of an intelligence drastically different from our own would lead to mere speculation, because we couldn't even begin to understand the motivations of say, an intelligent jellyfish.
Of course, the other problem is an intelligent species that lived on earth long before the humans and were wiped out couldn't really be associated with Atlantis. Like I said before, how would the story have survived long enough for humans?
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While there have been some odd discoveries of possible advanced technologies over the years, it is more likely that these( If they are real at all) come from space travellers who could have settled permanently or temporarily in one or more locations on earth. Such a possibility more neatly fits the earliest oral and written stories, such as the one which began this debate. Even the bible can, and has been, interpreted in this way.
I agree. While I don't discount the possibility that there was intelligent life that arose on this planet, Atlantis seems more fitting to an alien species. A small colony in one section of the planet would be most likely to leave no trace, or if it did, be isolated enough that it might never be found.
The only problem with an alien race running around here is that it would have had to show up when humans had been at least decently established in order for stories to have survived.
One last thought on Atlantis. Personally, I would love to make up a story like Atlantis and have people be speculating on it for centuries to come. The thought of everyone going nuts to find my mythical city makes me snicker in glee. So how do we know it wasn't just a joke?
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But i must agree that a floating city in the pegasus galaxy is the most appealing to me, as one who is an avid watcher of both the original Stargate, and Atlantis. You have to be avid when your local network puts new season's episodes on after 11 at night. Never mind. I have managed to collect the first 120 episodes on D.V.D. so far, and hope to eventually get the lot.
I am anxiously awaiting season 9 to come out on DVD. Though I am annoyed they finally started making slim packs, now that I've already spent a lot of money over the past several years on the other sets. The obsessive in me wants all the DVDs to match each other, while the practical part of me points out it's a waste of money. Sigh.