Science, Art, Litt, Science based Art & Science Communication
Earlier I wrote about convergent evolution that took very little time(1). Now we have another story of rapid one to show the deniers!
Deniers? ! Yes! Watch this video on how creationists confront the scientists asking them to show evidence of evolution over and over again :
The times have changed. And we are getting more and more evidence of evolution.
This discussion is added because scientists, science writers and communicators can confront creationists with evidence now.
Creationists don't accept DNA markers' proof because they cannot see it with their unaided eyes! This is my second discussion on such evidences.
Darwin would have loved to hear this!
Evolution is normally described as the consequence of freak mutations winding up helping a species adapt and change.
Florida lizards evolve rapidly, within 15 years and 20 generations!
Evolution is often thought of as being such a slow process that it can’t be observed. That’s not true, but to happen quickly, there usually has to be some sort of strong pressure on a population to drive any sort of fast evolution.
Scientists working on islands in Florida have documented the rapid evolution of a native lizard species — in as little as 15 years — as a result of pressure from an invading lizard species, introduced from Cuba.
After contact with the invasive species, the native lizards began perching higher in trees, and, generation after generation, their feet evolved to become better at gripping the thinner, smoother branches found higher up.
The change occurred at an astonishing pace: Within a few months, native lizards had begun shifting to higher perches, and over the course of 15 years and 20 generations, their toe pads had become larger, with more sticky scales on their feet.
The native lizards studied, known as Carolina anoles or green anoles, are common in the southeastern U.S. The invasive species, Cuban anoles or brown anoles, are native to Cuba and the Bahamas. Brown anoles first appeared in South Florida in the 1950s, possibly as stowaways in agricultural shipments from Cuba, and have since spread across the southeastern U.S. and have even jumped to Hawaii.
This latest study is one of only a few well-documented examples of what evolutionary biologists call "character displacement," in which similar species competing with each other evolve differences to take advantage of different ecological niches. A classic example comes from the finches studied by Charles Darwin. Two species of finch in the Galápagos Islands diverged in beak shape as they adapted to different food sources.
The researchers speculate that the competition between brown and green anoles for the same food and space may be driving the adaptations of the green anoles. Stuart also noted that the adults of both species are known to eat the hatchlings of the other species.
So it may be that if you're a hatchling, you need to move up into the trees quickly or you'll get eaten. Maybe if you have bigger toe pads, you'll do that better than if you don't.
There lies the stress and pressure to evolve as fast as you can! And it is happening!
Questions people asked about Evolution and replies by scientists:
Q: Why have basic life forms not evolved more?
Reply by scientists: 1. All life forms are continually evolving in response to the pressure of A very complex animal that evolved from a very basic life-form is, in fact, occupying the exact space as you are right now!
The reason there are still bacteria, and they never became people - is three-fold:
1. Evolution is parsimonious. It only goes as far as it has to. We don't develop super brains because we can function quite well with the brains we have. Bacteria don't change into plants because, actually, archaea (which includes bacteria) is the most successful life group on the planet - in number of species, in number of individuals and in total mass.
2. Evolution is driven by a change in the environment. If the environment doesn't change, genetic changes almost never confer advantages, so no "evolution" occurs. But if some members of a fish species mutate to be able to keep their gills wet out of water, and the environment gets drier, so that their lakes dry up, those members will survive to crawl to other lakes, continue to live and reproduce - and we have amphibians. That's called selection pressure.
3. If there's no genetic change, and that's totally random - it can be a copying error, a doubling in copying, a Hox gene turning on sooner or later, many, many things - there's nothing for selection pressure to act on - there are no different forms from which to select. (We have larger brains most likely because we went from a strictly tough vegetarian diet, which requird a fused skull almost from birth, to meat, then cooking, which ddn't require such large jaw muscles, a rigid skull [our skulls keep enlarging until about the age of 21] and someone being born with a Hox gene that did't turn on at borth, so his/her skull kept growing for a few years. Roughly - there's a lot more to it than that.)
HIV has no reason to change - its hosts (us) spread it around very nicely and it reproduces like crazy just the way it is. If it mutates to be a form that doesn't kill our immune systems, it'll be a different species of virus because it'll live longer in each host. (Mitochondria were once bacteria - now we can't live without them being part of our cells.)
2. There is a bit of a misconception about evolution that people tend to have when it comes to evolution. This assumption is that it is a constant, inevitable movement towards improvement.
In point of fact, evolution is a random process that can produce bad results just as often as good results. The reason it seems like evolution is always towards "better" forms is because the "bad" results tend to die out owing to the carriers of those evolutionary changes being more vulnerable to environmental dangers.
It also doesn't operate according to a clock. An organism may go tens or even hundreds of thousands of years without a single evolutionary change taking place, or a large number could happen within a few hundred years. The only real question with the timing is whether or not the species will be able to propagate these changes quickly enough for them to "take" or if they'll die out.
Then there's the question of these changes being able to make it for the long haul. Just because a "positive" evolutionary change has occurred in a species does not mean that it is guaranteed to last. Evolutionary changes merely shift the odds of survival and propagation a bit for the better or the worse. If a species has had a change take place only a few generations back and thus remains very localized on the coast, a single hurricane could potentially wipe that change out.
So, in essence, at any given moment, a species could randomly evolve, or not. Any given evolution could improve the survival chances of the offspring of the individual that underwent the change, or not. Any species whose evolutionary process has granted an improvement can survive long enough to spread out beyond a reasonable extinction risk, or not.
So if a species seems to have "failed to evolve" into a better form over millions, or even billions of years, it's not proof that evolution is false. It is simply proof that the species has genetics that are "good enough" to have survived and spread, and that some of the members of that species have not randomly evolved each generation since the evolutionary moment that created it in the first place.
Microbial resistance to drugs
I can give thousands of these references. It would be better if you read more about things before commenting on them.
Mosaic evolution - where subsets of traits evolve independently of others - painted lorikeets a rainbow of colour ...
Line of defense: Scientists report surprising evolutionary shift in snakes
What is the best evidence for evolution?
An international team of scientists has discovered a deep sea microbe that has not evolved (changed) for over 2 billion years. This is the greatest time for which no evolutionary changes have been observed in any living species till now.
Does it mean that an exception has been found for Charles Darwin's theory of evolution? No, say the researchers. In fact the organisms' lack of evolution actually supports.
The findings are published online today by the Proceedings of the National Academy of Sciences.
The scientists examined tiny sulfur bacteria that are 1.8 billion years old and were preserved in rocks from Western Australia's coastal waters. Using cutting-edge technology, they found that the bacteria look the same as bacteria of the same region from 2.3 billion years ago—and that both sets of ancient bacteria are indistinguishable from modern sulfur bacteria found in mud off of the coast of Chile.
"It seems astounding that life has not evolved for more than 2 billion years—nearly half the history of the Earth," said J. William Schopf, a professor at the University of California, Los Angeles and the study's lead author. "Given that evolution is a fact, this lack of evolution needs to be explained."
Charles Darwin's writings on evolution focused much more on species that had changed over time than on those that hadn't. So how do scientists explain a species living for so long without evolving?
"The rule of biology is not to evolve unless the physical or biological environment changes, which is consistent with Darwin," said Schopf, who also is director of UCLA's Center for the Study of Evolution and the Origin of Life.
The environment in which these microorganisms live has remained essentially unchanged for 3 billion years, he said.
"These microorganisms are well-adapted to their simple, very stable physical and biological environment," he said. "If they were in an environment that did not change but they nevertheless evolved, that would have shown that our understanding of Darwinian evolution was seriously flawed."
Schopf said the findings therefore provide further scientific proof for Darwin's work. "It fits perfectly with his ideas," he said.
The fossils Schopf analyzed date back to a substantial rise in Earth's oxygen levels known as the Great Oxidation Event, which scientists believe occurred between 2.2 billion and 2.4 billion years ago. The event also produced a dramatic increase in sulfate and nitrate—the only nutrients the microorganisms would have needed to survive in their seawater mud environment—which the scientists say enabled the bacteria to thrive and multiply.
Schopf used several techniques to analyze the fossils, including Raman spectroscopy—which enables scientists to look inside rocks to determine their composition and chemistry—and confocal laser scanning microscopy—which renders fossils in 3-D. He pioneered the use of both techniques for analyzing microscopic fossils preserved inside ancient rocks.
Metabolism: Evolution retraces its steps to advance
Bacteria in a long-term evolution experiment evolved a new metabolic trait via two separate mutations with opposite effects.