[rv77ax]

(^ that was the longest comment i ever read on HN)

there is one thing that i don't understand about evolution.

if evolution is true than human, bear, elephant, and any-big-animal-that-exist-today-except-whale should be the "biggest" thing that happened today, after evolving. but, why there is exist monstrous animal like t-Rex, whale, mammoth, etc. ?

EDIT: for anyone who could not see my face when typing this, "that was the longest comment i ever read on HN" is a compliment, not a sarcasm.

[dkokelley]

Natural selection states that the most fit for survival will survive. When applied to evolution, it means that humans were better-suited for survival than t-rexes.

Think about it like this: A T-Rex has to eat a lot of food to survive. What happens when there is a shortage of food? The T-Rex can kill and eat just about anything, but it need s a lot of it to survive. Humans aren't as fit to kill things as T-Rexes, but they are smarter, and they don't need to eat as much, and they can survive on plants too. Humans could grow and store food, so they survived. Dinosaurs weren't smart enough to grow or store food, so they had to eat when they found food, or not eat. They didn't survive.

(Please, nobody 'correct' me by saying that a meteor killed the dinosaurs. For this example, it was their small brains.)

[gort]

"humans were better-suited for survival than t-rexes"

A bizarre statement, given that the two never existed at the same time.

Yes, it was indeed a meteor that killed almost all the dinosaurs (except a group of theropods that had evolved wings and survive to this day). Evidently the shrew-like mammals of the time were better suited to the post-impact environment. We evolved from them.

[dkokelley]

sigh

You didn't get my point. I intended to use food requirements and storage as an example to show how the more fit for survival are selected to reproduce.

I know that my example was an over-simplification. I was trying to meet the parent half-way so that he would understand.

[rv77ax]

so, every body know that meteor killed almost all the dinosaurs. but no body is telling me ? it's some kind of public secret or what ?

[gort]

Apparently.

The first major clue is the presence of iridium (a metal common in asteroids) at exactly the right place in the rocks (the Cretaceous-Tertiary or "KT" boundary, dating to 65 million years ago, which is also when non-avian dinosaurs went extinct). That was discovered around 1980 by Alvarez et al.

Further research has led us to the Chicxulub crater near the Yucatan Peninsula as the impact site.

Now you know.

[Lozzer]

Given that T-Rex survived for about 3 million years, and that Homo Sapien is up to 0.5 million I'd say the jury is sitll out.

[chrischen]

I'm not sure I understand what you're getting at.

Are you saying that things can only evolve to become physically bigger, but not smaller? Why is that true?

[rv77ax]

> I'm not sure I understand what you're getting at.

there is a theories that say human ancestor evolve after dinosaurs extinct, and another theories say human and dinosaurs live coexist.

so, if i take first theories it's like saying "how can a thing evolve so big like dinosaurs, but human does not exist yet ?"; or if i take the second theories it's like saying "OK, first experiment is fail, let's try evolve to another morph" same like saying we evolve because an accident.

see, how confused am here ?

> Are you saying that things can only evolve to become physically bigger, but not smaller ?

no. i believe it's become smaller.

FYI, this evolution-y thing is new to me, in fact i don't care, until recently. it's not as much as am interested in tech and music. so please forgive me for my poor knowledge. and asking does not mean rejecting.

[chrischen]

> ...and another theories say human and dinosaurs live coexist.

Are you sure that wasn't a movie?

I've never heard of the theory that humans and dinosaurs coexisted, at least not with credible evidence. It's probably something the creationists propagated.

Evolution is partly by chance. But evolution takes millions of years. So basically, what are the chances of something like humans eventually coming along? Well apparently after millions and millions of years and countless iterations of random morphs the chances are good.

It's like a startup, except without smart founders behind it. That's why it takes so long and so many iterations before evolution gets it "right." With a startup if you get something wrong you change it because the previous method failed (if you don't change it the startup fails). In evolution the species that doesn't get it "right" fails. The iteration of the species that does get it right obviously continues to thrive. So over millions of years there are constantly new iterations and the best ones make it through to now.

If this is new to you, it shouldn't be. Where are you from? As far as I know all schools in the US should get you up to speed with evolution. But judging from your writing you're probably not from an english speaking country?

[rv77ax]

i came from east, Indonesia, where most people here had a strong faith with their religion. No, we didn't learn much about evolution here, the only thing that we learned about evolution in school was about some species of bird in Galapos islands, that's it.

Because of the environment where i live, i did not have a good resources like sciences book, articles that cover it up. it's not even something that you can talk along with your teacher/professor/people, because of the strong culture and religion here. Even if i ask some of the "smart" people here i can guest what their answer, "it's not true" end of discussion.

Then, recently, i read a lot of news/articles about evolution in internet, first i just skip it and then later thought come to my mind, "why, why science peoples and some people had very strong opinion/faith about evolution". i really want to know base of their opinion/faith.

Reading some or any articles in Internet it's just not enough, because some of them will accept it and some of them will denied it. seriously, no one just can change their faith just because read some paper ? it take some serious talk, arguing, and sometime some prove. right ?

i know that by asking question or discussing about evolution here will not fulfill the void in my mind, first, not every people here is evolutionist; second, i believe it will be a long, long, discussion.

so, as a first step i some of question that i keep long enough in my mind here (as you can see above, voted down to minus. i hope it's just because my writing skill, not because my stupidity and curiosity ;). i hope some one understand my position here.

to continue our discussion,

Are you sure that wasn't a movie?

no, it was some article i read. See, this is where i become hard to believe just any article i read.

In evolution the species that doesn't get it "right" fails.

part of me believed that was true, because i see and read some species become extinct. if i am not wrong, some species in north pole.

[chrischen]

If you reason it out, you can see why species that are weaker fail, and their genes are not passed down. After millions of years of filtering down: survival of the fittest, and mutations, which introduce new sets of genes of genes into the mix, we get the better So called "evolved" genes in the end.

Also evolution is not faith based like religion, it is evidence based. I wouldn't really say it's an opinion or preference.

I don't know why people are so trigger happy with the down votes. for the record I didn't down vote you. I think it was 'cause your comments were a little confusing, but that doesn't merit a downvote in my opinion.

Let me know if you have any more questions.

[jballanc]

This reminds me of a classic trick question that I would ask my biology students: What is the most evolved organism on the planet today? Did you say "humans"? BZZZT! Wrong!

Consider that evolution is the process where by an ecological niche exerts selective pressure on a population and, by doing so, causes certain "best fit" traits to become enriched in that population. It stands to reason then that an organism that has remained in one niche for a long time will have experienced the greatest enrichment of such traits. Now consider the lowly bacteria: most species of bacteria have not moved from their niches in millions or even billions of years. Now consider the viruses that infect these bacteria. All evidence indicates that they've been around even longer!

Do you have a pet? A cat or a dog maybe? How often do they get sick? How often do you get sick? Ever wonder why that is? You see, disease is, as the name implies, a dis-ease experienced by an organism that hasn't achieved a good balance with its environment. The longer a species has to adjust to its environment, the better balance that it can strike with the other organisms, that might function as pathogens or parasites, that share its environment. When it comes to humans, we are probably the least evolved organism on the planet by this measure because we're one of the newest! (Not surprisingly, most of the species which have appeared on the planet more recently than humans are human pathogens.)

Size, as a selected trait, has its own very interesting properties in evolution. If your smaller you ratio of volume to surface area is greater, and therefore you loose more heat. This greater heat loss is made up for by a faster metabolism and warmer core temperature. (Ever taken your cat's temperature?) All evidence indicates that faster metabolisms are also linked to greater frequency of ROSes (reactive oxygen species, not rodents of unusual size ;-) and subsequently a shorter life span. Most organisms that we know that fall into this category compensate for their shorter life span with a greater reproductive rate (litters of 6 or 8 are common for cats, less so for humans).

On the other hand, if you're a large organism then your volume to surface area ratio is low, and you'll do a better job of retaining heat. The flip-side of this, however, is that you require a greater abundance of food and a longer period of development to maturity. Also, you will live longer (fewer ROSes) and so you don't need to reproduce in as large numbers. That's a good thing, because each of your offspring will require a greater investment of resources.

The upshot of all of this is that size really has little to do with "how evolved" an organism is and everything to do with their environment. Larger species tend to dominate when food is plentiful. Larger species also tend to only appear at the tops of food chains, where threats to their few offspring are lessened. All of this, it should go without saying, is a generalization and there are certainly exceptions to the rule.

Really, the only advantage that humans have over any other organism on earth is cognitive ability and a capacity for introspection and curiosity. This is, honestly, what upsets me the most about the whole creationist/ID movement: proponents of this view are essentially asking you to give up that most essential of human traits, the desire to ask questions, and instead accept their "god" or "creator" as an adequate explanation. Instead, I think it is our responsibility to take advantage of this unique capacity that we have and develop some humility. We need to realize that we're the new kid on the block, so to speak, and that while life on the earth will continue with or without us, we have a choice as to how much of an impact we have on our niche. Humans would do well to recognize that we are, so far, a fairly maladapted species. We have a long way to go...

[radu_floricica]

As depressing as it may be, evolution is not something that is going towards anything. It is simply what remains. I find that the best direction metaphor is that everything is falling down, and occasionally passes a sieve. The maximum complexity (minimum local entropy?) may grow somewhat, but at best that's a side effect.