# Evolution - why human vulnerability ? **URL:** \ **Category:** Great Debates\ **Created:** [October 7, 2003, 11:21am UTC](https://boards.straightdope.com/t/evolution-why-human-vulnerability/206031 "2003-10-07T11:21:06Z")\ **Posts on this page:** 12\ **Page:** 3
**Author:** ![Marley23](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Marley23](https://boards.straightdope.com/u/Marley23)\ **Post date:** [October 8, 2003, 12:44am UTC](https://boards.straightdope.com/t/evolution-why-human-vulnerability/206031/41 "2003-10-08T00:44:25Z")
It seems to me that smart vs. strong isn’t a balanced equation. A human who is quite weak in comparison to a smilodon or a mammoth only needs to be smart enough to use a spear against it to survive. I’d argue that a little smarts goes further than a little strength. Whatever amount of intelligence we have right now leaves us with a leg up on any animal regardless of how strong it is. ---
**Author:** ![Rashak\_Mani](https://avatars.discourse-cdn.com/v4/letter/r/ea666f/32.png) [@Rashak\_Mani](https://boards.straightdope.com/u/Rashak_Mani)\ **Post date:** [October 8, 2003, 1:00am UTC](https://boards.straightdope.com/t/evolution-why-human-vulnerability/206031/42 "2003-10-08T01:00:44Z")
I saw a foto of a White Hunter that was attacked by a leopard in Africa and killed it barehanded. Humans might not be specialized… but they arent such a pushover as some seem to imply… “modern man” is naturally too way out of shape and lacks the experience that primitive man had in defending himself… without tools or weapons too. Our relative size helps. Still muscle to size wise a chimp is 5 times stronger than us… ---
**Author:** ![Spectre\_of\_Pithecanthropus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spectre_of_pithecanthropus/32/12343_2.png) [@Spectre\_of\_Pithecanthropus](https://boards.straightdope.com/u/Spectre_of_Pithecanthropus)\ **Post date:** [October 8, 2003, 4:50am UTC](https://boards.straightdope.com/t/evolution-why-human-vulnerability/206031/43 "2003-10-08T04:50:20Z")
> [@](#): > > \*Originally posted by The Shill \* > \*\*Asteroide dude, > > Yeah, this evolution thing has selected our brains/intelligence/dexterity etc. All very useful and all that. > > In fact, so useful that our physical vulnerability has become irrelevant. We built weapons to hunt, so we didn’t get killed despite our physical weakness. We found ways to shelter from the elements, so we survived even though a cold human may not have survived the winter. Our physical weaknesses became irrelevant as we found ways to overcome them without removing them. So there was no need for evolution to ‘deselect’ them. > > All good practice for our evolving minds. \*\* Another factor here is that whatever the evolutionary advantage is, it costs food–calories–to maintain. The thick bones and powerful musculature of modern apes, and earlier humans, require a lot of fuel to be built and maintained. It also takes energy to fuel a larger brain, but my guess would be that it doesn’t take as much. So once somebody learned that they could take animals down with sticks and clubs, or, working cooperatively, hunt very large animals, there was no looking back. ---
**Author:** ![Badtz\_Maru](https://avatars.discourse-cdn.com/v4/letter/b/e36b37/32.png) [@Badtz\_Maru](https://boards.straightdope.com/u/Badtz_Maru)\ **Post date:** [October 8, 2003, 6:16am UTC](https://boards.straightdope.com/t/evolution-why-human-vulnerability/206031/44 "2003-10-08T06:16:44Z")
I think our hairlessness helps us run farther before we overheat. We not only have relatively thin hair for apes, we also have much more active sweat glands I don’t think it can be explained as a neotenous side-effect, as newborn chimps and gorillas have much thicker body hair than humans do. A pack of hairless hominids would be able to chase prey longer than hairy ones, or be able to run longer to avoid being prey. ---
**Author:** ![EllisDee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ellisdee/32/4531_2.png) [@EllisDee](https://boards.straightdope.com/u/EllisDee)\ **Post date:** [October 8, 2003, 8:00am UTC](https://boards.straightdope.com/t/evolution-why-human-vulnerability/206031/45 "2003-10-08T08:00:19Z")
I saw a Discovery Channel show that tried to explain why we are “hairless”. The answer was that humans got the greatest adaptation of all…the ability to dissipate heat. This came in the form of sweat glands and fine hair. (Rhinocerous, etc… can’t sweat, so they hang out in mud and water a lot. Same with elephants.) This gave us the ability to be active during the day, unlike all other large meat-eaters on the Savannah. So we ended up being able to hunt much more effectively than our hairy counterparts. It also allowed us to migrate during the day, and do the exhaustion-style hunting mentioned by a previous post. (The heat dissipation thing is what gives us our endurance. At least, during the day.) It also may have contributed to agriculture, something about being able to work the fields during the day, but that’s just a WAG and my timeframes may be way off. The numerous survival benefits of our heat dissipation came at a price: our skin, due to the sweat glands, can’t be tough like leather. Seems a fair tradeoff. (Although, I wouldn’t mind being a night-adapted creature…feline night vision would be cool.) ---
**Author:** ![Latro](https://avatars.discourse-cdn.com/v4/letter/l/a87d85/32.png) [@Latro](https://boards.straightdope.com/u/Latro)\ **Post date:** [October 8, 2003, 9:44am UTC](https://boards.straightdope.com/t/evolution-why-human-vulnerability/206031/46 "2003-10-08T09:44:12Z")
What’s all this stuff about leathery skin? Do humans have thinner skin than other animals? Rhino’s and oliphaunts excepted, of course, I’ve never heard of this. Someoine got data on that? ---
**Author:** ![Dogface](https://avatars.discourse-cdn.com/v4/letter/d/9d8465/32.png) [@Dogface](https://boards.straightdope.com/u/Dogface)\ **Post date:** [October 8, 2003, 12:45pm UTC](https://boards.straightdope.com/t/evolution-why-human-vulnerability/206031/47 "2003-10-08T12:45:40Z")
> [@](#): > > \*Originally posted by sghoul \* > \*\*JRDelirious, > > Ok, if we did in fact come from quick enduring sneaky alert little guys, what happened? We lost much of that. Without work, we are none of those things. Why would they go away? Wouldn’t being alert AND smart be better than just alert or just smart? \*\* Prove that our species ancestors also did not have to “work” to develop those potential traits. I’m waiting for the evidence. Show some real evidence instead of nothing but fart-gas speculation. ---
**Author:** ![dropzone](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dropzone/32/7515_2.png) [@dropzone](https://boards.straightdope.com/u/dropzone)\ **Post date:** [October 8, 2003, 1:25pm UTC](https://boards.straightdope.com/t/evolution-why-human-vulnerability/206031/48 "2003-10-08T13:25:29Z")
> [@](#): > > \*Originally posted by Darwin’s Finch \* > \*\*Remember that the entire organism, and its associated genome, is what gets “selected”; natural selection does not pick and choose individual genes from a genome to continue on. \*\* Of course not, but a single mutation that provides a sufficiently large disadvantage, such as allowing the organism to freeze to death at night, will be selected against that night. Apparently short, fine hair did not provide enough disadvantage in the climate of East Africa at that time, nothing that couldn’t be countered by piling together like a pack of dogs to sleep or, possibly, through an early use of fire. While I don’t disagree with much of your neoteny theory, I still don’t see what it has to do with our relative hairlessness. \*\* > [@](#): > > It’s more a case that (pick whatever trait you choose) turns out to be a workable solution (or, at the very least, not a hinderance)\*\* Ah, evolution in a nutshell! Even if a trait doesn’t help the organism survive, if it doesn’t help KILL the organism (at least before it breeds) it can stay. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [October 8, 2003, 1:31pm UTC](https://boards.straightdope.com/t/evolution-why-human-vulnerability/206031/49 "2003-10-08T13:31:16Z")
> [@](#): > > Ellis wrote: > It also may have contributed to agriculture, something about being able to work the fields during the day, but that’s just a WAG and my timeframes may be way off. Your point about hunting during the day is a good one. The above idea, though, doesn’t cut it. I would suspect that having brains to figure out how to plant and grow things was the deciding factor re: agriculture. Just a WAG, you might say.🙂 ---
**Author:** ![dropzone](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dropzone/32/7515_2.png) [@dropzone](https://boards.straightdope.com/u/dropzone)\ **Post date:** [October 8, 2003, 1:41pm UTC](https://boards.straightdope.com/t/evolution-why-human-vulnerability/206031/50 "2003-10-08T13:41:20Z")
But gathering foodstuffs, as people did back then as their primary means of support, is a whole lot easier to do in daylight, though it is just as easy at dusk or dawn, which allows you to crash during the heat of the day. We might be getting too hung up on hunting which probably was NOT their main activity. ---
**Author:** ![Darwins\_Finch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darwins_finch/32/20304_2.png) [@Darwins\_Finch](https://boards.straightdope.com/u/Darwins_Finch)\ **Post date:** [October 8, 2003, 4:07pm UTC](https://boards.straightdope.com/t/evolution-why-human-vulnerability/206031/51 "2003-10-08T16:07:22Z")
> [@](#): > > \*Originally posted by dropzone \* > **While I don’t disagree with much of your neoteny theory, I still don’t see what it has to do with our relative hairlessness.** Neoteny is the retention into adulthood traits which are present in the juveniles of the ancestral stock. Hairlessness is a common fetal trait among mammals; slow down development sufficiently with respect to the growing of hair, and you have hairless adults. As in humans. We can, in some ways, be likened not so much to juvenile chimps, but to _fetal_ chimps. So, again, it is not so much the case that a specific gene pertaining to reduced hair was gained (or a gene which produced thick fur was lost), and _that_ is what resulted in our hairlessness, but rather the trend towards neoteny was what was selected for (to be honest, I’m not sure how the specific mechanisms of heterochrony work, but I suspect they have a lot to do with genes which affect the timing of development, rather than new genes which produce the traits directly). This process / trend / whatever accounts for our flat faces, thin body hair, large brains, and so on. ---
**Author:** ![Urban\_Ranger](https://avatars.discourse-cdn.com/v4/letter/u/e9c0ed/32.png) [@Urban\_Ranger](https://boards.straightdope.com/u/Urban_Ranger)\ **Post date:** [October 8, 2003, 4:35pm UTC](https://boards.straightdope.com/t/evolution-why-human-vulnerability/206031/52 "2003-10-08T16:35:48Z")
We don’t have to be invulnerable, we just have to be better than our direct competitors. Happily, we were. So we won. [Previous page](https://boards.straightdope.com/t/evolution-why-human-vulnerability/206031.md?page=2)