Wow.
Yes, it's real, but the question of course is: Why? If evolution is driven by natural selection for best fit within an organism's environment, what possible advantage could such armor provide? Why on earth would a beetle develop such horns? Why for that matter would an Irish elk (now extinct) carry around a rack with a width of 10-12 feet and a weight of 70-90 pounds? And why on earth would a peacock develop those beautiful, yet extraordinarily cumbersome feathers? When in flight, peacocks make turkeys look as graceful as geese.
Darwin theorized that another evolutionary process was at work in cases such as these. He called it sexual selection. Basically, Darwin theorized that females would choose mates who would offer the most protection, or the most successful hunter, or highest quality genetic material. Recent studies seem to bolster this idea.
Researchers tried shortening some of the plumage on male peacocks. Not dramatically - just a few inches. Yet the outcome was indeed dramatic in terms of preferences expressed by the peahens. Males with cut feathers were passed by in the mating process. Regardless if they were known or unknown to the females. Peahens seemed to make a conscious choice to select the males with the more extravagant plumage to father their brood.
Other organisms develop weapons to fight for the attention of the female. The Irish Elk is one of many animals that carried it's weapons around with it. Males actively fight for the females' attention. The greatest warrior won. Many examples of this remain today.
In the case of the rhinosaurus beetle pictured, an evolutionary arms race began millions of years ago that lead to the pronounced claws on the beast. This dung beetle doesn't merely push its ball of dung along a path for furtive consumption. It burrows under the dung, and drags the dung into its own tunnel network for storage and consumption. These tunneling beetles have developed their armor and huge claws not for defense, but rather as a warning. Two males may approach, they wave their claws, they perceive the threat to each other, and one will aver and back away. Claws may interlock, and the combatants may assess their relative strength, rather than inflict actual damage. Males can signal the intent, as well as their relative strength. And once again, females notice this, and it plays a role in sexual selection.
What about humans? As noted in the NY Times article which discussed this, our teeth are puny. We don't have claws. We don't look terribly menacing. (Well, most of us) But we DO manufacture our weapons. We do signal our intent. Think of the samaurai's sword. Or the military parades of tanks and gun carrying soldiers. Or the opening of the movie Iron Man.
But I gotta tell you - if I can find a helmet on eBay that looks like this rhinosaurus beetle....it's mine.
(the article on which this post is based can be found at http://www.nytimes.com/2009/03/24/science/24armo.html?pagewanted=1&ref=science)
12 comments:
First off, this beetle does look exactly like a rhinoceros, so that's pretty neat. It's interresting that this one species not only has armor and "weapons" to fight off other males, but also a bright color that would be useful in attracting females. Usually, only one of these traits is developed but it's not very often that we see both. Peacocks have bright feathers that woo females but no protction from other males or predators. On the other hand, elk are virtually the same when it comes to color; the difference is that they have large antlers to fight off other males.
The process of natural selection is an extremely interesting topic. It is taking place right now even though we can't see it. Though it seems that humans have hit a plateau in their evolutionary paths. We have developed with no beautiful colors, claws, or even horns. Part of the reason that we are now evolving at such a slow rate, in comparison to other species, is that no matter if your the dominant male/female or not, people are still reproducing and passing their traits on. The topic of the future of the human race is very debatable and I'm not going to get into that. But here's an interesting question, if all other species continue to change and evolve while humans remain basically the same, will humans be able to cope with the changes of the future?
In response to Sam's question, it seems to me that even though the bodies of humans aren't evolving a lot, we are constantly changing our surroundings and methods of doing things. One reason is because our brain is very developed in comparison to other animals. This makes it possible for humans to evolve in others ways rather than through changes of the body. For example, we don't have armor or weapons on our body like many animals, but we have learned to create weapons by using the resources around us. Nations are constantly racing to create new and more powerful weapons, which seems like a form of evolution. Also, our bodies don't change colors or develope pretty patterns in order to attract a mate. Yet, we have others ways of doing this, such as wearing certain types of clothes or acting a certain way. There are always new fashion trends, which might be concidered a type of evolution as well.
This isn't completely on topic, but, after watching the movie in class, I thought that it was really interesting that each of the millions of sperm produced by a male are all different. This means that there are a ton of different possibilities for what types of traits and charactertics a baby will have. It is also completely random as to which sperm will make it to the egg. Therefore, it is by complete chance which traits your baby will exhibit.
-Amanda O.
While we as humans don't have extravagant markings, such as colored feathers or antlers we still undergo the same process of natural selection. Instead of choosing the most colorful male/female we choose one that is most attractive to us based on other physical features; ie. eye color, height, smile, muscles etc...
Also, though we have no physical weapons besides our fists, humans have the intelligence to create our own weapons. Things such as guns, nuclear power, and swords. While in no ways would these be necessary in trying to attract someone of the opposite sex, sometimes, these weapons are needed for protection.
I would have to say that most people do not know what they actually want in a mate. I guess it is like choosing a favorite color. We have them but we don't know why, but really at the same time we like a few other colors. We don't know why we just do. If we think about it harder we could probably come up with a reason why we like a few of those colors. But we are not really sure why we liked the color we chose first. We chose it the instant we saw the color. The question we will never know is "why"? I guess humans are so indecisive we really like all colors in different ways. See the connection.
Andy H
I must agree with everybody who has blogged so far. However after reading everybody responses, I'm curious do you think that before our ancestors learned to walk as biped; did they have any of these "traits", such as a tail as a possible weapon or maybe a distinctive look that attracted the opposite sex. In additon, I was also wondering, since we’re talking about genetics and how people get certain eye color. Why is it that the color blue did not show up in humans, Neanderthals, until approximately 43,000 years ago or the trait for red hair? (Looking at:http://ngm.nationalgeographic.com/2008/10/neanderthals/hall-text).
When you think about it, us humans basically all look the same. I mean yes, we have different skin colors, eye colors, height, weight ect., but we all have the same general body structure. We aren't blessed with huge antlers or colorful feathers and shells, but we do still have a similar process of sexual selection. We all are attracted to different traits and characteristics, just as animals are.
After reading this blog entry it makes me think about why us humans are made the way we are. How is it that we can all have the correct and precise bone structure that allows us to do everyday things? And what would it be like if we were all made completely different? Would there be a lot more problems, diseases or injuries that would occure? Or would it be a better, more interesting world to live in?
-Heidi
I think, we're not that different from some of these animals. I can see a peacock in a lot of persons. =)People show what they have to impress the "target". In the movie we watched, there was one scene, on the beach, when the woman said that nearly all of the people were doing something in order to reproduce. Getting tan, working out,... we have to earn what the peacock already has. Something to get attantion.
Fights between two males are not uncommon among humans. They might be a little more abstract than baning one's head against the opponent until one gives up. But there is even poetry about men fighting over women...
I guess we don't need armor on our bodies, since we are smart enough to create it ourselves.
So, basically, I'm something like an Elkpeacockbeetle.
It's getting out of hand, I will stop here. Good evening
I find it really cool that different creatures look for different characteristics in their mates. I think for humans it is more complicated, because some people might look for a good smile, but others might look for a toned body.
There are many people who also try to find mates that have a good personality. It's all very complicated...It seems much more easy for other creatures, because they find specific things like patterns on feathers or how big antlers are. I think they have it easy on that aspect.
~Stacy~
It's funny how creatures evolve certain traits in order to better attract a mate; brighter plumage, big horns, a nice smell, ect. I find it strange that often times these things aren't beneficial in any other way. I imagine the peacock's plumage doesn't work very well to hide the bird from potential predators and I doubt the rhinoceros beetle's horn is very useful for fending off predators. These traits have really only one use--to attract a mate. It's interesting how these traits, which are possibly harmful to the survival of the individual animal (bright feathers giving the animal away to predators) are essential for the animal to attract a mate and reproduce.
-Michael Diamond
Ok so I think we're more like the peahen. Humans also are more attracted to people with certain specs. Like some humans like people with nice hair, others with nice eyes, and others with both. Unlike the peahen each human is attracted to different things as a mating partner. In a way you can say that people are attracted to how succesful another person is and how their personality, rather than just their looks. But looks does play a good role. As you can see with early teenagers, who are going through a maturity stage, their hormones are going crazy, and by taking them as an example, they would most likely (as I can remember from that time in my life) choose someone they find attractive.
I find the beetle quite amazing though. The colors and shapes are fantastic.
-Elsa C.
Wow, that's one strange-looking beetle. I would personally think the female beetles would be more attracted to the males who don't look like a rhinoceros, but that's just me.
I think it's interesting that the process of natural selection gives us so many wildly different results. You'd think that, if the reproduction of all species is governed by this one principle, that all species would gradually evolve to be pretty similar to each other: if having claws and teeth and being able to run really fast makes an animal more likely to survive, why aren't we all lions? I guess it's just surprising that some species, given the chance to evolve over millions of years, are still basically helpless against their predators. (Yes, I include humans in that statement. Unarmed human vs. lion--who do you think would win??)
Personally, I'm not sure that the process of natural selection is as big a deal as in the animal kingdom. Sure we compete for more attractive mates like they do, but a big thing today is that there is somebody for everybody, which from what I've seen is true. With animals, the weaker ones generally don't get to mate, so their weak traits aren't passed on, but this is not the case with humans (and why don't we have super-squirrels then? they've had millions of years to become super-awesome). Other than people like Hitler, most humans don't seriously deem other humans as "unfit to reproduce" even if it's someone we wouldn't neccesarily choose. I think mainly with humans is that it's more about the quality of the mate instead of whether or not they can fend off a pack of rabid wolverines in the middle of the night when the nest is under attack.
-Daniel G.
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