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A question about past evolution on earth

I did read your post . But I don't know whether dolphins are sentient. They are intelligent but so are certain breeds of dogs. I do not consider dolphins sentient. Are dolphins able to recognize themselves when they see their reflection in the mirror? I know that the Apes can.

I think you're misusing the word "sentient." Which is understandable, since most science fiction misuses it too. As I've been saying, sentience just means awareness and the ability to feel emotion, pleasure, or pain.
Yes, sentience (self-awareness, perception of one's environment, and the capacity for sensations such as pain and pleasure) is often confused with sapience (the ability to reason and to apply knowledge).

Thanks for explaining what sentience and sapience actually mean. I was not aware of their correct definition.
 
Well, scientists have just discovered why dolphins haven't developed sophisticated technology. It seems they instead float about, using puffer fish to get high.

news link

"After chewing the puffer and gently passing it round, they began acting most peculiarly, hanging around with their noses at the surface as if fascinated by their own reflection."

And we thought sea turtles were bad for drug use.

They should have teamed up with the pot making dinosaurs.
 
Yes, sentience (self-awareness, perception of one's environment, and the capacity for sensations such as pain and pleasure) is often confused with sapience (the ability to reason and to apply knowledge).
Thanks for making this clear (particularly since my dictionary made no difference between both - in my language there are several words for both and interestingly some of them are identical)

There are quite a few examples for self-aware species. All of them are highly intelligent and as far as they are physically able to so so they also use tools/technology.
These include (apart from many others) :

In the water: dolphins and certain whales who recognize their own images, use tools for hunting (they create a kind of net made of air bubbles which the fish don't dare to swim through. It works like a fishernet). Plus: dolphins have a complex language that includes a name for every individuum.

Airborne species: Ravens and related species: they, too, recognize their mirror image, have a language (but as far as we know no individual names), and use tools they make themselves, for example specially shaped wooden hooks to stir out maggots from holes in trees.

Terrestrian species: humans, gorillas, orang utans and bonobos. I think I needn't elaborate on them.

Interestingly, we don't know about any subterrannean species who are self-aware. However, we have a few that use tools: for example, certain ants harvest leaves and chew them to a mass they mix with the mycels of mushrooms who's fruit are their main food. They are active gardeners who not only sow and harvest but also prepare the soil themselves.

If we are looking for signs of previous self-conscious species (excluding human or pre-human species) it gets a lot more difficult: with an extinct species we can not observe if they'd recogize their reflection. If we restrict ourselves to searching for tools: we haven't found any yet. But as the recent examples (see above) show, tools needn't necessarily leave traces to be found.
So the question whether there has been self-conscious life on this planet before us and our colleagues with feathers or flippers can not be answered.

Was there intelligent life before us? That very much depends on your definition of intelligence.

We can not prove if there was intelligent life before us, if we define intelligence by use of a language, tools or applying mathematics.
If, however, we define intelligence as the ability to adapt to new situations by considering several alternatives and perhaps even finding a completely new solution then yes, every individuum has intelligence to a dregree that at least permits it to survive. I think we may safely assume that this rule also applied in the past.
Predators that hunted in packs needed intelligence to hunt successfully. Their victims needed intelligence to escape.

Even plants, bacteria and amoeba can learn. From the point of view of a biologist that ability to learn counts as intelligence, too.
Perhaps the question should rather be: has there been/is there a form of life that was/is not intelligent?
 
^^ I'll bite my tongue. :D

I don't think it's impossible that there was a prior civilization on Earth. If it never made it past the very primitive and local stage before coming to an end, the evidence may be hard or impossible to find. It may be underwater now, or buried by glaciers. It may have existed someplace like the Yucatan and been obliterated by an asteroid impact. I have a tendency to doubt it, though. Given the length of time there has been complex life and the relatively short time it took humanity to go from low-hanging branches to the Moon, I think we're it.

Actually, I think this thread is touching on what I've long thought is the solution to the Fermi Paradox. As Christopher said, during most of the existence of the planet, life has been unicellular. It's dangerous to make assumptions from only one example, but from what we see here it seems that both the jump to complex life and the jump to a high-order civilization are difficult. It seems likely that the universe is teeming with life, but most of it is single-celled and most of the rest is non-technological.
 
Another interesting thing:

It is possible that there are many civilizations in the universe, many of whom very similar to ours, facing very similar questions to the one that we do. While it is unlikely that there was a previous civilization on our planet, some of those civilizations will discover previous ones on theirs. If we ever meet them, they will have some stories to tell, and we would be imagining in their places.

Some will have other kinds of interesting things to tell. Thus, making contact with alien civilizations might turn out more fruitful than anything else we've found down here. For any single fascinating thing that we hope to uncover on our planet, there are ten more fascinating things that are waiting for us at the house of our stellar neighbours.

(If we don't have stellar neighbours in the near 1000 light years, the chances of a previous Earth civilization also plummet.)
 
Another interesting thing:

It is possible that there are many civilizations in the universe, many of whom very similar to ours, facing very similar questions to the one that we do. While it is unlikely that there was a previous civilization on our planet, some of those civilizations will discover previous ones on theirs. If we ever meet them, they will have some stories to tell, and we would be imagining in their places.

According to Christopher, Multi cellular lifeforms have been around for 450 millions of years. We modern humans have been around for 100 000 to 200 000 years. We diverged from the chimps and apes around 4 to 6 millions of years. So basically Humans took around 4 to 6 millions of years to evolve to the present state after we separated from the apes.

450 millions years of Multi cellular lifeforms evolving seems long enough for other species to become sentient and sapient, considering that humans went from ape to human in 4 to 6 million of years.
 
^Well, there's no regular clock to these things, no preprogrammed "upward" progression of evolution. Evolution is just adaptation to environmental change, so whether, when, and how the environment changes has a lot to do with it. It tends to follow a pattern of punctuated equilibrium: species stay pretty much in a single form with only limited, subtle change as long as the environment remains stable, then go through rapid bursts of change when the environment changes. Since different planets wouldn't be expected to have environmental changes or cataclysms coming at the same pace or the same time, there's no reason to expect evolution to proceed at an equivalent pace. It could be faster or slower. And there's no guarantee that the changes will be in the direction of greater intelligence. It's certainly a useful adaptation, but it carries a metabolic cost. And it depends on a number of different evolutionary innovations cropping up and interacting constructively, and there's no guarantee they'd all arise or come together the same way on every planet.

Indeed, the same goes for the emergence of multicellular life. Life on Earth stayed single-celled for three billion years before the innovation of sexual reproduction randomly emerged and allowed evolutionary change to accelerate enormously. But there's no reason we know of why that change couldn't have happened two billion years sooner or a billion years later. We just can't assume our single example is typical or predictive.
 
According to Christopher, Multi cellular lifeforms have been around for 450 millions of years. We modern humans have been around for 100 000 to 200 000 years. We diverged from the chimps and apes around 4 to 6 millions of years. So basically Humans took around 4 to 6 millions of years to evolve to the present state after we separated from the apes.

450 millions years of Multi cellular lifeforms evolving seems long enough for other species to become sentient and sapient, considering that humans went from ape to human in 4 to 6 million of years.

Call it nitpicking, but we humans never diverged and seperated from apes.
We still are apes.
Everything that makes an ape an ape is still present in us as it's in chimps and gorillas among others.

While you are claiming that it took humans to evolve from the earliest simpler apes over several million years you can claim the same thing about bonobos and it will be just as true.

So the time frame has very little to to with the rate of advancement or direction.
 
We aren't apes. Humans and apes evolved from a common ancestor we have yet to completely find.
 
Then define what makes an ape an ape and how that doesn't include humans.

Humans share a lineage with chimpanzees who themselves split into modern chimps and bonobos after they split of from our ancestors.
humans and chimpanzees split of from gorillas before that and humans, chimpanzees and gorillas all share an ancestor with orang-utans.

It is not undefined ancestor splits into humans and all the other great apes who develop independently from that moment on.
 

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We aren't apes. Humans and apes evolved from a common ancestor we have yet to completely find.

Absolutely wrong. It used to be believed that hominids (family Hominidae) were a separate family from the great apes (family Pongidae), but genetic studies have proven that we are very much a member of the same family. Now, the family Hominidae is defined as encompassing humans, chimpanzees, gorillas, and orangutans. It has a subfamily Homininae which includes all of those except orangs. Thus, humans are a subset of the great ape family.

http://en.wikipedia.org/wiki/Hominidae
 
But I thought we were monkeys?

2nibtqa.jpg


:D
 
Apes and monkeys are distinct families. Monkeys are usually smaller and have tails, which apes do not. Calling an ape a monkey is about as accurate as calling a bear a raccoon.

Monkees are a different matter. You never know where they'll be found.
 
^^ AAAUGH! :mad:

The scientific name for modern humans is Homo sapiens, Latin for "wise man." The "s" is NOT an English plural ending.

There is NO SUCH THING as a "homosapien"! :brickwall: :brickwall: :brickwall:
 
Actually our connections are a lot more complicated than scientists claim. Although humans seem to be related to monkeys, not all humans are even related to each other, which is why when you read an article that includes two people who have the same last name, the writer will often have to say "(no relation)".

For example, if I wrote about Loni Anderson, Gillian Anderson, Pamela Anderson, and Richard-Dean Anderson, I'd have to put (no relation) all over the place, as I would if I wrote about Hugh and Cary Grant, Rock and Kate Hudson, Michael and Diane Keaton, Tommy Lee and Katherine Zeta Jones, etc.

So these people are not at all related to each other, yet somehow are all related to Clyde from "Every Which Way But Loose." It doesn't make a lot of sense, because it implies that Gillian Anderson's ancestors branched off from Richard Dean Anderson's ancestors long before the australopithecines walked the Earth (because they're unrelated), yet they ended up not only working in the same industry, but the same genre. What are the odds of that?
 
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