Thread: Darwin and evolution

Question 1:

Many people have a morbid fear of snakes and spiders yet not of cars, although there is usually a far greater risk of being killed or maimed by the latter than by the former. How might this fact be explained in evolutionary terms?

Question 2:

How can the obviously non-adaptive changes associated with old age be explained in terms of natural selection?

Question 3:

Why can't you do your own homework?

Why can't you get a life?

Originally Posted by Ted

Why can't you get a life?

Clever comeback, I haven't heard that one since the 7th grade

You appear to still be in the 7th grade if you're attaching emoticons to your answers.

Originally Posted by Ted

You appear to still be in the 7th grade if you're attaching emoticons to your answers.

I try to maintain my inner child.

Or you just a loser who hangs around science forums all day?

Gee I dunno, cars are useful in every day life; snakes are only useful in research. Besides, you can't get wheelspin, do a handbrake turn or run someone of in a snake. Nor can you stash the body of a human in a snake.

Originally Posted by Ted

Or you just a loser who hangs around science forums all day?

Clearly, but insulting me isn't going to get your homework done. I don't see how being a loser would be mutually exclusive from maintaining my inner child though.

Absolutely riveting scientific discussion and debate. I'm on the edge of my seat here...

Originally Posted by Ted

Absolutely riveting scientific discussion and debate. I'm on the edge of my seat here...

If you offer your own opinion on the question others are going to be much more willing to provide assistance if you actually seem to be putting effort into it rather than just looking to cheat your way out of doing your homework.

Okay guys, the sniping in this thread will stop now or I will lock it.

Ted, if someone feels like taking the time out to answer your questions then that's great, but don't expect it. Generally we take a dim view towards people joining up merely to get their homework questions answered, and it appears very much like that is what you have done. We also don't appreciate sarcasm from someone who hasn't made a meaningful contribution to our community.

i_feel_tiredsleepy, you're better than this. There was no need for the opening shot there.

We aren't evolutionarily primed to fear cars. We created cars as a species. We generally are primed to fear either the unknown or objects that are known to cause harm. Yes, car accidents occur but most of my friends and family have been driving for 15 years or so safely. We fear immediate dangers more readily than uncertain danger.. we can use higher reasoning (prefrontal cortex, etc) to justify driving until we get into an accident and, via the amygdala, the danger becomes immediate and we shit our pants, cry for mother, etc...this is a very very simplified answer...ask a neuroscientist or neuropsych major for details...

Question 1: Think about how many generations of people need to die from a certain object before others who avoided that object begin to out-reproduce them. Then, compare that to the length of time cars have existed. Evolution is long and slow. I'm talking tens of thousands, and often millions, of years. How long have we been being hit by cars?

Question 2: Evolution acts by reproduction. It's generally only when something is prevented from reproducing that it will impact the evolution of that animal (I'm way oversimplifying to make a point). Since reproduction tends to happen early in life, negative health stuff with old people is rather irrelevant. Unless those negative health issues occur prior to reproduction, they can essentially be ignored. However, you might wish to review the grandmother hypothesis, and consider the impact on the kin unit of having elder more wise members around to teach, protect, and car for organisms with similar genes.

Question 3: I_feel_tiredsleepy is quite right. Next time, lose the attitude, and let us know what YOU think first... where you're struggling... and ask if people can give you feedback on your own answer. Nobody here wants to wipe your ass for you, but we'd be glad to tell you where you're doing it wrong or how to do it better or what to watch out for next time. If you keep being snotty, come in showing an unearned sense of entitlement, or don't display any effort of your own then people will be far more likely to hand you poison ivy instead of toilet paper when you ask for help.

Actually, I think Ted's questions are very valid. The fact that they have both been discussed on this forum before does not alter that. Ted, no doubt, did not see the earlier discussion.

On the first question, iNow's reference to time is very correct. Humans have lived a modern life for a very short time, and we have not had time to evolve to adapt to modern dangers. However, we lived a hunter/gatherer tribal existence for the best part of 200,000 years as Homo sapiens, and for a hell of a lot longer than that as pre-humans. We evolved behaviours to avoid the dangers present in this much longer period, and that included such things as snakes.

On the second question, iNow is also correct. The length of time a harmful mutation stays in the human gene pool before it is eliminated by natural selection is a function of the age at which it strikes.

For example : progeria strikes in childhood. This harmful mutation lasts no more than a generation or two, before the deaths of those carrying the mutated gene removes it from our gene pool.

Hemophilia is a harmful mutation causing loss of ability of blood to clot. People carrying this gene tend to die young, and the gene is eliminated from the gene pool within about a dozen generations. The reason it takes this long is that a lot of hemophiliacs survive long enough to reproduce. This is even more true today, with medical treatments.

Huntingtons chorea is a disease caused by a harmful mutation that does not normally strike before age 40. It is still eliminated by natural selection, but this may take 50 to 100 generations.

However, what of the harmful mutations that strike well after people become grandparents? Those mutations will stay in the human gene pool and accumulate. Thus, old people show the harmful effects of many nasty mutations.

Originally Posted by skeptic

Actually, I think Ted's questions are very valid.

Of course they are valid questions. That is why they were set for homework.

Thank you skeptic. Some intelligently proposed answers finally.

The questions are not my homework, as has been suggested. I'm 34 years old and they were discussed by me and some friends who work in conservation down the pub. We tend to have intelligent discussion in Britain. That's why we've been at the forefront of science, amongst other things, for centuries.

I'm sorry I didn't offer my thoughts initially. I was just interested to see what others thought first.

What I didn't appreciate is snide comments straight off the bat, especially to a newcomer to the forum. Hence the sarcasm.

I shant bother with this forum anymore and I'm especially not taking flak from people who live in a country that still teach Creationism in their schools.

Let me start by saying that I'm not happy at all with how people reacted to this thread. Science forums, rightly or wrongly, will tend to be seen as sources of knowledge that might not be easy to find elsewhere. We will get random new posters with questions, sometimes delivered verbosely with their own opinions and sometimes not. If anyone feels disinclined to go to the trouble of replying, then that's just fine- don't post. Let the thread sink. We prefer our new posters to engage with us more but we're not going to encourage that by scolding them and certainly not by being sarcastic with them. The next time I see such behaviour I will be issuing warnings.

Originally Posted by Ted

Thank you skeptic. Some intelligently proposed answers finally.

The questions are not my homework, as has been suggested. I'm 34 years old and they were discussed by me and some friends who work in conservation down the pub. We tend to have intelligent discussion in Britain. That's why we've been at the forefront of science, amongst other things, for centuries.

I'm sorry I didn't offer my thoughts initially. I was just interested to see what others thought first.

What I didn't appreciate is snide comments straight off the bat, especially to a newcomer to the forum. Hence the sarcasm.

I shant bother with this forum anymore and I'm especially not taking flak from people who live in a country that still teach Creationism in their schools.

Ted, I'm sorry that you received such an unnecessarily frosty response- and I'm quite peeved at some of the posts made by our regulars here- but quite frankly your response was not at all helpful either. I suspect you'll find that one of the main reasons why the British have had a central role in science over the centuries is because British scientists are traditionally polite, open-minded, and willing to deal with international collaborations in a spirit of respect. The cause of the German Albert Einstein was advanced by the British astrophysicist Arthur Eddington, for example. Something which would not have been possible had Eddington taken the xenophobic attitude you appear to have adopted. He certainly would not have risen to such meagre provocation.

For the record, we tend to have intelligent discussions in many places other than Britain and, although there is a strong fundamentalist lobby in inow's home of Texas, Creationism is not taught in schools in any of the countries of origin of those posting in this thread. I would be quite delighted if you would stay and contribute to discussions here. If you can lose the prejudiced attitude, then I can say that for my part I will endeavour to ensure that you are treated with respect in return.

Since it seems few of us here are able to play nice, I must now, regrettably, lock this thread.