With the Earth being 70% ocean why wouldn't humans, the most sophisticated and complex form of life be biologically engineered for aquatic lifestyle?
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pleiades (
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October 13th, 2013
I do not mean to be pompous in my question. I hope you catch my drift and overall mood of the question. Lately I’ve been struggling to get my thoughts to others. My wording is horrible, and it’s worse if I were trying to speak.
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36 Answers
Our brains make us technologically adapted for water life.
Because evolution doesn’t have an endgame. Or even a playbook.
There is an intellitent species in the oceans: Dolphins. So- we are on land, they are in the water…
Because life is not engineered.
Humans evolved on land, and there is no evolutionary pressure to adapt to an environment a lifeform does not live in.
Also, the only standout feature you apes have is your brain. Everything else about your body is, compared with other animals on your planet, massively inferior.
“most sophisticated and complex”, haha, what a joke.
There was no evolutionary pressure to move into water. If the atmosphere thinned out over a few million years, exposing us to high UV radiation, maybe our ancestors would start moving back to the water for protection. I’d love to see flow through gills as an option. Seems like that would be handy
I can hear it now: “Dude! Check out the set of gills on that one!”
Who do you suppose engineered humans as land mammals?
For what it’s worth, there are mammals who returned to the seas. We call them ‘whales’
There are no warm bodied animals that are able to breathe in the water. I wonder if the supply of oxygen taken directly from the ocean is sufficient to produce enough energy to fuel our brains.
Warm blooded animals require a lot of energy. There is a theory that the use of fire for cooking is what allowed the human brain to evolve, since it redirected energy from digestion to the brain, which consumes most of our caloric input. The answer to the question may simply be the difficulty of building a fire in the ocean.
@ml3269 is right, you’ve got the dolphins and other cetaceans who are highly intelligent.
In fact they could easily be more intelligent than humans, unless you define intelligence in a Darwinian sense that they dominate all the other species on the planet.
@LostInParadise All the cetaceans are warm-blooded, whales, dolphins, porpoises.
They have metabolic adaptations and layers of fatty insulation that help them deal with the temperature of the water.
“There are no warm bodied animals that are able to breathe in the water.” Do you mean being able to get their oxygen out of the water like a fish? That’s true.
As @ragingloli has said, “the most sophisticated and complex form of life” is simply not true. We are as ‘evolved’ as every other species on the planet. We just happen to be better at domination (and even that could be up for the debate, the bacteria that colonize us get around just as well as we do), that doesn’t make us ‘more sophisticated’. You can say that our brains are the most sophisticated, and you’d probably be right, but that’s just one adaptation.
And long answer short, again as @ragingloli said there was no adaptive pressure to go back to the ocean for our particular genetic tree. Adapting to the oceans involves costly modifications to the body, and so would not occur without significant sustained pressure once we got onto land. And as also mentioned it did happen to other mammals, but our lineage simply never had that. Without that pressure, it usually will not happen (neutral drift occurs, but to have that carry us into the ocean would be highly improbable).
although the earth is 70% water most of the ocean is very nutritionally poor. once you get into the open ocean nutrient levels, unless you’re a balleen whale, are very low.
The land has much more intake options.
Aside from some of the other good responses in the thread (though I haven’t read them all), you may also still be a victim of the former (now mostly defunct) view of evolution as a “tree”, with bacteria and other single-celled organisms at the bottom, proceeding “upwards” toward more complexity, more mobility, more “whatever” (including intelligence) with apes and other primates occupying branches somewhat “below” mankind, and Man at the top of the tree. Does that sound familiar?
That’s a defunct view of evolution, because a better analogy is to a “bush”. Man is just one of the shoots in the bush, not necessarily “better” or “more evolved” than any other organism. (In fact, it might be fair to say that bacteria are the single biggest success in evolution, since they have been around since the beginning of time on the planet, and have followed multiple evolutionary paths to survive at extreme high and extreme low pressure; oxygen-rich and oxygen-starved environments; high heat and freezing cold, and all kinds of other environments that would be deadly to most other terrestrial organisms.)
Because of the advantages we have as a species, we have been able to spread far and wide and succeed (from a species standpoint) at the expense of many other species. This does not make us “better” than any other species, however.
Man, in this view, is not “more evolved” than other species, including bacteria, fungi, plants, whales, monkeys and apes, or dogs or cats. We just followed a different evolutionary path to get to where we exist today. For all we know – assuming we don’t kill its chances through any of the various means that we might do that – there may be another marine or amphibious animal that might evolve in ways that could (if allowed) rival mankind’s dominance of much of the planet’s surface. (And I don’t for a moment suppose that “mankind dominates” the surface of the planet. That honor still belongs to bacteria. And worms.)
@rojo Ugh, that ‘hypothesis’. I was worried someone would bring it up. It’s a joke, not a hypothesis. It was at one point possible but it doesn’t actually fit with what we know of our evolution anymore. Note that the supporters it mentions are a writer, a clinician, and a surgeon, not paleontologists or evolutionary biologists.
Also, annoyingly they decided not to give the profession of the (only one) detractor they quote: he is a paleobiologist, someone actually trained in the evidence.
There is a stage in the development of the human embryo where gill slits are evident. Perhaps we could have gone that way if we had not progressed to living on land. I learned that in my college physiology class.
@Sunny2 embryonically we go though the entire cycle of our evolution from single cellular to multi cellular colony to specialized tissues to early vertabrate to amphibian to primate to human. The gil slits that disapear is part of that progression
^^ ( ontology recapitulates phylogeny ) I remember.
If anything we evolved farther and farther away from living in the water, meaning down under the surface. Supposedly our skin got lighter and lighter to absorb D (although you have probably seen me say I think our skincolor also is like camoflauge often matching the environment we lived in) but I do think the D is a factor. We need to be able to absorb enough, hold onto enough, and if we lived like the fishes we also would be different in other ways I think. We would not just be humans with gills.
Some good answer here. We biologists do not talk about the luck factor much in evolutionary processes but that could have been all there was to this. A land zig instead of a water zag. Of course water does not lend itself well to hand dexterity for example.
I could go on in this vein but that might be one of the main constraints; tool making hands
@drhat77
Tool making =/= tool use.
Some birds use tools, too, but you will not see any crow building an electric drill.
@ragingloli yes that is true, but that’s a limitation of the brain on the hand. but if you combine the tool using hands of an otter with the tool using brain of a human you may have a tool using aquatic creature.
But I just realized – underwater = no fire. no fire means we need to use more resources to digest than our food. I’ve heard bandied about that our ability to cook food allowed us to divert more engery to our brains.
@drhat77
” Otters use tools ”
———————————————-
” tool making hands ”
A subtle but real difference that was pointed out to you.
” yes that is true, but that’s a limitation of the brain on the hand. but if you combine the tool using hands of an otter with the tool using brain of a human you may have a tool using aquatic creature.”
Otters are not aquatic creatures, but I see your point. Still, the luck factor and the adaption to the immediate environment ruled the otter out specifically and no other creature seems to have filled that brain/hand gap. Otters are rather deleterious though.
” But I just realized – underwater = no fire. no fire means we need to use more resources to digest than our food. I’ve heard bandied about that our ability to cook food allowed us to divert more engery to our brains. ”
Very good point! The more energy to the brain part is when certain proteins/fats/carbohydrates are pre-digested, so to speak, by cooking. The chemistry of polymer to monomer reduction is facilitated by cooking.
@Neodarwinian deleterious… like humans whenever they move into an ecology? eh? eh?
@drhat77
Hit the wrong spell correct choice!
Dexterous!!!.
We come from the water, we do not belong to it. Salt content % of ourselves vs. the oceans is the same.
@KaY_Jelly , @LostInParadise Sorry, unless they can provide campaign funds they do not meet the necessary criteria to be people.
I have that book mattbrowne. Its wonderful…
Pleiades:
You could say human beings are designed for the ocean. That is, your body’s water and salt content pretty much mimic that 70% figure for the Earth’s salt water content…
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