h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Mostly, I agree with those who have said that there seems to be little evidence that would really challenge the fundamentals of evolution.

Just a passing comment, though, about that famous study with the moths which 2legs referenced - I seem to remember hearing that it has recently been discredited to some extent. The researcher compared old butterfly collections with what he caught himself, but the light ones were prettier or something, so the collections probably weren't very representative. So he may well have got the "right" answer for the wrong reason...

I have to agree with Wulfric in that I am still somewhat shocked to find that the evolution theory is under such scrutiny. I always grew up believing in it as we/I was not taught any other way at school, not even in R.E.
I also have to agree with him on having a lack of knowledge of the scientific fundamentals and how they were brought about in this theory. I too et a little lost in all the theoretical talk, but i think i have the jist of it
So this is really just a bookmark

Someone on HooToo in another thread mentioned a perfect example of an intermediate species. Is it a bat? Is it a rat? Noooo, its a flying squirrel...

But perhaps the most poignant example of evolution is the HIV virus. We can't vaccinate it because it evolves. Our immune systems can't deal with it because it evolves. The strains that were around 10 years ago aren't now. New strains are seen to evolve within a single carrier.

and then there is the Duck Billed Platypus

"Just a passing comment, though, about that famous study with the moths which 2legs referenced - I seem to remember hearing that it has recently been discredited to some extent."

It was. Actually, it was shown that the coloring of the peppered moths didn't actually matter, because the moths never rested on the trunks of the trees. They lived up in the leaves, where they were hidden no matter what color they were. The photographs of the moths on the tree trunks were partially faked, because they were usually glued on to the trunk. After all, how are you supposed to get a good picture if they're way up in the tree hiding behind all of those leaves?

Actually the HIV virus is just a newcommer. Virus mutation is why you get a cold each year. You can't get the same cold twice because you get antibodies for that one so it mutates and you get the result next year.

There is a point being missed. Science is wrong and it always has been and that is what is so great about it because each time it's proven wrong then we learn something.

In the early 1970s, cloud cover told us that Venus most likely had oceans. Then the russians landed a probe there.

The interesting question is: What's the real difference between Mutation and Evolution?

Not being any kind of "expert," I will just jump in here. The difference between mutation and evolution is... Mutation occurs all the time, at random. It makes for a little diversity within one species (cf. blue eyes, brown eyes, green eyes, the occasional kid with red eyes and very very white hair...) Most of the time, mutation does not even make a notable difference.

Sometimes mutation gives an individual an advantage. Slightly better eyesight, for example. Now, this individual can see better and might be (if such are the circumstances) better equipped for survival. (In the "modern world," good natural eyesight does not seem to matter that much, anymore, as we can get prescription glasses and whatnot.)

In most such cases, this mutation does not reoccur in the next generation. But if, for some lucky coincidence, the mutated individual meets another individual of the opposite sex with the same mutation, or if the mutated gene happens to be dominant, their offspring can have the same advantage.

If this happens at a larger scale, the species as a whole might benefit from the mutation. The new trait becomes the new standard. The species has evolved.

Mutation is the basis for Evolution.

Or that is, at least, how I remember things from my biology classes back in school.

Y.

evolution is the system, or process. Mutation is a tool in that process.

Is a flying squirrel actually related to bats? I thought of the flying squirrel as an interesting side branch. Ho hum, never really thought of it before.

Of course, the existence of intermediary fossils such as are often mentioned, presupposes that evolution progresses by gradual stages with small changes each time. This is by no means certain and macro evolution could also be at work.
e.g.
http://www.smh.com.au/articles/2004/03/30/1080544467566.html
http://dailytelegraph.news.com.au/story.jsp?sectionid=1260&storyid=1101413

He didn't mean that a flying squirrel is the intermediate stage between bat and rat. But some people argue that the bat can't have evolved, because if it wings were shorter it would not be able to fly and not able to walk very well either because of dragging those large skin flaps around. So it would probably be killed by predators. But the flying squirrel shows that full flight is not necessary to survive. If you looked at bats a million or two years ago, they would probably look quite like flying squirrels do today.

You often hear someone argue that something couldn't have evolved, as making a change to it would mean it would be useless. So it must have sprung into existence fully formed. Like the "half an eye is useless" idea.

Darwin explained the process as 'descent with modification'. Individuals are not perfect copies of their parents, and will change randomly over time. When some particular trait becomes advantageous then this will tend to spread through a given population, and in time possibly through a species. If two populations become separated, then environmental pressures will probably make the advantageous changes (Darwin's 'mutations' were simply changes) different. If they become different enough, a new species may evolve, either as the different populations won't interbreed because they look or smell different or now have different mating signals etc., or because they are no longer genetically compatible. So mutation is just change at a local level, and evolution is what we call the larger scale changes over a longer period.

"If you looked at bats a million or two years ago, they would probably look quite like flying squirrels do today."

Ahem - http://www.enchantedlearning.com/subjects/dinosaurs/facts/Pteranodon/

Why can't bats be a decended sub species?

I'm bigger, stronger and medically healthier than both my parents. However I share a trait, green eyes, that my parents both have that their syblings and parents didn't have. My point is that the modern human race has little to do with natural selection anymore. I didn't choose my wife based on genetic traits and my rareish eye colour is almose certainly doomed as she has brown eyes.

May I jump in?

I'd just like to say that the theory of evolution isn't debated too much within the scientific community. There's just too much evidence that supports the theory that all life evolved from a common ancestor (read Niles Eldredge's The Triumph of Evolution and the Failure of Creationism for an excellent work-up of this from a dog-centric point of view). What you'll find paleontologists and biologists at odds with are the mechanisms of evolution, and exactly what group fits in where on the tree of life.

there are lots of theories about evolution but there aren't any facts to support religious ideals that god made man. they don't have any proof to support their ideas. darwin on the other hand has all the facts.
religious people can't handle the fact that we did come from sub-species of animals. now who's the monkeys uncle now?

To me, comparing religion and science is like comparing the Gregorian calendar to the Internet. Unless you take a really, really wild leap of the imagination, you can't do it. Science is the process of finding a natural explanation for phenomena. Religion deals with God (or gods), who are by definition above nature, and therefore can't be explained by science. What burns me is when creationists present science and religion as two alternate belief systems, when there really isn't a way you can do that.

Many scientists are very deeply religious. Myself for example, I'm a geologist and a Russian Orthodox Christian. I just happen to think that Genesis and most of the old testament was written as an allegory. Don't call me an atheist.

Just a rant. I'm giving a presentation on this in a few weeks. Got to get it ready!

What did you mean by that pteranodon link? Bats probably are related to flying squirrels, as they are both rodents of some kind. But I don't think they are closer related than bats are to other more grounded rodent species.

Early bat. As in prehistoric, not 2.00 am

http://www.mun.ca/biology/scarr/Icaronycteris.htm

found
"A heated debate was recently triggered by the discovery that flying foxes, primates, and flying lemurs share a unique brain organization. (Flying lemurs, apparently close relatives of the true lemurs of Madagascar, are a poorly known group of cat-size gliding mammals that live in the Indonesian region and, like bats, are in a separate group of their own, the Dermoptera.) Did both the Micro- and Megachiroptera come from a single, shrew-like, gliding ancestor, or did the flying foxes evolve separately from primates? If the latter notion is correct, are their unique brain characteristics sufficient reason for reclassifying flying lemurs and flying foxes as primates? The issue remains unresolved, but most scientists agree that bats are far more closely related to primates than to the rodents with which they often are linked in the public mind."

at

http://www.batcon.org/discover/species/naturalhistory.html

One point nobody seems to have come back to was the assertion that science can't explain explosions in evolutionary diversity - I presume this refers to events such as the cambrian explosion.

I've seen several theories on this. Mass extinctions leave large areas of unexploited habitat which may be exploited by may new types of species with as yet no natural predators (an explanation of opportunity rather that mechanism). My favourite theory on mechanism is the analysis of HOX genes with genomes.
HOX genes are our "master control genes" they tell a cell whether it's a brain cell or a muscle cell for example. Remember that all our cells have the same DNA - what makes one a neuron and another a muscle, or a skin cell, or a liver cell...
The answer is our HOX genes, these are active in the foetus and control our body's shape and function early on in development.
Study of many species has shown the these HOX genes are conserved almost exactly all throughout verterbrates (we all have five fingers, a spine, a brain etc in roughly the same orientation). Simple oranisms have fewer. We have 16 (I forget the exact number, that's a guess as an example), molluscs have 8, segmented cretures have only four....etc. Ie. the more HOX genes, the more complex the animal is able to become.
Anyway is has been proposed that the open environment left after the mass extinction involving the trilobites in the Cambrian period) coincided with a geometric increase in the HOX genes within life's various genomes and the hence a geometric explosion of animal and plant life diversity, hence, the "explosion" in terms of the diversity and number of species at that time.

I'm not saying that's what happened but it's certainly a possible explanation and an interesting theory.

So science can explain such things, proof of such theories will never come though unless someone invents a time machine to go back 500 million years and a time slowing machine to observe life evolving over a geological time scale.

Also the cambrian explosion (and the other lesser ones) were 'explosions' only in geological time. They actually took a helluva long time to happen.

Science really doesn't "prove" anything. It can only disprove. And if theories have stood up against many, /many/ attempts to disprove them, chances are they're as close as we're going to get to being right. With evolution, no scientific study has said "no, all life didn't evolve from a common ancestor." I hate to use a universal negative, but someone show me a peer reviewed study that shows that one species of life on earth is entirely disconnected from everything else.

Your timetable's a bit off. Trilobites originated in the Cambrian, diversified during the Ordovician, were hit hard by the Devonian extinction, but didn't disappear until the Permian.