Study: Fish underwent 'reverse evolution'

OT: If fish are evolving why aren't we?

I got mine!

See, they were spot on all along. ;)

"Damn you GW Bush, Damn you democrat(s), it was only going to be a few short years until all the least-armored humans were gone!"

the height of evolution of humans. when our brief time on this planet ends, all other living creatures will breath a sigh of relief.

and women's breasts are developing sooner and are larger.

man made hormones are in the air, water, and food causing this.

fish in the Potomac River are same sexed; males baring eggs; and every other sexual combinations.

oby/gyns should fess up and tell us what they know.

Either way I would love to see the evidence you have, as for women and their breast size that could logically be explained as women having access to food on a more regular basis than they used to.
The fish part I know about but the oby/gyn part kinda sounds a bit nutty, no offense.

and or soft puffy nipples


have no evidence that a larger amount of girls are developing larger breasts. just my own observance.

I do know there is evidence that girls are maturing much, much, sooner. (bleeding)

How much younger, got a link to the data?

nt

It's a non-genetically based response to environmental polutants.

what then?

The changes you're describing are at the level of the phenotype rather than the genotype.

Gene frequencies don't have to change for organisms to pass down traits useful in a specific environment. Organisms with different, sometimes radically different phenotypes, can have identical genomes, and these phenotypical differences are heritable.

http://en.wikipedia.org/wiki/Epigenetic_inheritance#Evolution

Marginal notes on environmental stresses can be coded into the genes of an organism's offspring without changing gene frequencies, and these notes influence the phenotype of successive generations. In the case of a fish it's possible that increased predation could cause stresses in the surviving parent fish that signal succeeding generations to develop more armor.

This sort of controversial research dredges up all the horrors of Lysenko's Lamarkism, but the mechanisms are a very basic part of life's genetic tool kit. In a limited way successful species can often adapt quickly to environmental changes without going through all the bother natural selection.

A rather frightening aspect of this has to do with the loss of heirloom species in agriculture. Many of these heirloom species have a greater capacity for epigenetic inheritance than the finely tuned (and sometimes genetically modified) crops we now depend upon for our survival, and are thus more likely to be useful as the earth's climate becomes more unstable.

Reverse evolution = evolution.

A change to an ancestral state...you can call it a homoplasy or even a reversal. But I really hate the term reverse evolution. It gives people the wrong idea of what is really going on.

Oh yeah...and human beings are evolving. Maybe a little slower, since environment has less effect on us due to our adaptability and our ability to change our habitat. But we are evolving. EVERYTHING evolves.

:banghead:

The options for personal selection are greater than at any time in human history. I can go out and find any sort of mate I want anywhere in the world... that will have me anyways. I'm of the opinion that this may create an artficial "bottleneck" of sorts.

Cool story thanks for posting!

Natural selection requires a loser. Individuals with unfavorable traits don't pass on their genes, while individuals with favorable traits do. Over time, this process permits those favorable traits to become common throughout the population. You have evolved.

The problem today is that while YOU can select any mate, so can anyone else. Medicine and technology have largely eliminated the idea of people with unfavorable traits dying off before breeding (darwin award contestants aside), so everyone passes on their genes.

Given enough time, this will eventually lead to the homogenization of the genetic pool, which is the exact OPPOSITE of evolution (which depends on genetic diversity as a driver for species change).

Human homogenization isn't necessarily a bad thing from a social standpoint (though it has some medical implications), and evolution isn't required for our growth as a species. It just means that, if you fall into a glacier now and don't get thawed out for 50,000 years, you'll be greeted by people who look no different than we do now.

And you could have evolution take place within different segments of the population.

Whereas it's widely accepted that proximity is the most important factor in mate selection, followed by similarity in both looks, culture, upbringing, interests etc: given that we have a much larger geographical roaming range and a much larger pool of possible mates, statistically on average it would seem that people will continually and successfully select for those most like them.

That would lead to divergence over time no? Though you would likely still have a bell curve, could either end of the curve not get fatter? And then given a bottleneck (say like space colonization or the break down of modern society) could there not be the emergence of a new species?

Where were you born? Where were your parents born? Where were your grandparents born? Where were your ancestors 150 years ago? 500 years ago?

Location is not a good selective pressure because it changes over time. Evolution, even in an ideal situation, requires a static population to be exposed to the same selective pressures over multiple generations.

Interests vary generation by generation as the world changes, and they aren't subject to genetic predisposition anyway. Two bookworms marrying can easily have children who abhor books.

Cultures evolve over time, limiting the selective pressure of culture. Even OLD cultures like China's, which can be traced back thousands of years, have changed substantially over that period. Cultural cues as a selective pressure aren't steady enough to influence a large population over many generations.

Ditto that with language.

How about looks? Pretty people can have ugly babies, and vice versa. Also, the definition of beauty tends to vary over time and between cultures, making it an unreliable and inconsistent evolutionary pressure, though I'll concede that it's a possible one...there's a theory that redheads are the result of preferential breeding practices based on a desired visual trait. While this kind of preferential reproduction MAY be able to alter the frequency of the appearance of some traits, however, I don't think it qualifies as evolution. The traits were always there, and the last time I checked, we redheads are still the same species as the rest of you...and that our numbers are actually declining every generation.

Mating with people "just like you" can only drive evolution if two things are happening. 1) All of society has to do it. 2) There has to be a genetic driver behind the similarity. If you have ANY kind of substantial interbreeding between the groups, you will be introducting enough genetic diversity to undermine any evolutionary changes. And if there isn't a genetic driver for the "preference", there will be nothing to select for.

First of all let us not forget that beauty is largely a matter of symmetry. People from every culture universally rate those with a higher degree of symmetry to be more attractive. For that matter even babies will stare significanly longer at people who's features are symmetrical. The cultural component is by and large a question of preference for body type. However the ratio of hips to shoulders remains consistent... as a matter of fact it is mathematically consistent with the golden ratio. Beauty is then likely more in the eye of your genes than your culture.

Beauty is also highly correlated with intelligence, financial success, and a longer lifespan.

As I said in my previous post: the bounds of location have been greatly diminished. Therefore people can be far more selective about who they mate with than at any other time in history. This could easily concentrate certain traits in different segments of the population; A sort of virtual bottleneck.

It has been found that the more alike people are on many dimensions, the more likely they are to be attracted to each other and the more likely they are to stay together... and have children.

Evolution doesn't have to take place quickly. It can just as easily happen slowly over time, through the slow deliberate accumulation of traits.

just kidding, of course.

"reverse" evolution is a pretty silly phrase.

It's bad enough when creationists misunderstand and misrepresent evolution, but when the good guys muddy the water in this way, it doesn't help.

knows what "reverse evolution" means. In fact, I've seen the term used too many times in real science journal articles. But it's one of those dumb ideas scientists get to name stuff, which then gets picked up by people who then get confused about what's going on.

Personally, that sloppy usage of language, even if it is jargon that scientists use, is a pet peeve of mine. Reversals aren't even that big a deal. They happen all the time, especially in insects.