We all know the story. Life’s existed on this planet for 2 billion years, and during all that time, nearly all creatures used four legs to get around. Then, merely 15 million years ago, a bunch of chimp-like creatures stood upright, evolved a thumb, and proceeded to dominate all other species on the planet, nearly extincting themselves in the process.
Why did it take 1.985 billion years for animals to discover the utility of thumbs? Some dinosaurs walked upright, but they never evolved a thumb. If they did, would intelligent life have evolved much sooner? Would there be civilization 65 million years ago, consisting of dinosaur-like bipeds instead of the current monkey-like form?
My opinion; it’s because the animals to evolve high intelligence were vertebrates, which have only 4 limbs. If vertebrates had 6 or more, it would have been much easier to evolve specialized forelimbs for handling things.
We’ve only had thumbs, tool use and intelligence for a relatively short space of time; whether they are workable survival traits in the long term is yet to be demonstrated.
Life’s been around for more like 3.5 billion years, for most of which time nothing used legs at all (unless you want to count cillia as legs). Once legs did catch on, most creatures with legs (right up to the present day) have used six of them to get around. Add to that, that while thumbs and intelligence are both kind of nifty, they’re really only super-powerful in combination. And even with that combination, organsisms with both thumbs and intelligence are still a far cry from dominating the planet.
I believe it was Gould who pointed out that this is not now the age of humans, nor was there ever an age of dinosaurs. It is now, and always has been, the age of bacteria.
This is true. However, if water insects or allosauruses developed thumbs & intelligence and dominated the earth for a very short period of time, before succumbing to their own waste and global warming, there would certainly be geological evidence of it – maybe not in fossils, but certainly in stuff they left behind (like pyramids, Cadillac ranches, etc…)
Because obviously I was high when I posted it. :smack: Hey mods, can I thumb a ride over to the proper forum?
Life’s existed on this planet for around 4 billion years.
Very, very few creatures used 4 legs to get around. At a guess less than 0.0001% of creatures used 4 legs. The vast majorityof creatures used no legs, and amongst those that did/do have legs well over 99.999% of them used 6 or more legs.
It’s highly unlikely that bipedalism in chimp-like creatures was used prior to 5 million years ago.
Opposable thumbs are a deifning characteristic of the primates. They existed since well before any primate started walking upright.
“Nearly extincting”?
How are human ‘nearly extincted’? We are by far the most abundant large mammal species on the planet and our population is increasing steadily.
It didn’t. Animals don’t discover things like thimbs, they come about as a result of evolutionary experimentation.
No. As I noted above, all primates have thumbs, only one lineage and a dozen or fewer species ever possesed ‘intelligence’. Having thumbs hasn’t made monkeys or even lemurs intelligent. Instead having intelligence has allowed one branch of the homioid family to utilise their thumbs for soemthing other than climbing and grabbing food.
To sum up, they didn’t. The thumb is just a special case of an opposable digit. Opposable digits have been around for a long time in bipedal, arboreal and arial vertebrates. And if we include the invertebrates you could say that the claws and scissors of various arthropods should count as well, in which case “thumbs” have been around for a long, long time.