by cantleave 271 Replies latest members adult
The giraffes neck would either evolve through natural selection...or it would become extinct because it couldn't evolve fast enough. - still thinking
Sadly, many species cannot evolve fast enough. Consider how many species are close to extinction now. Consider the trilobite, the Passenger Pigeon.
Cofty: I have writen you some more stuff about pseudogenes you may find helpful.
Thanks for that Cofty. And sorry, I said it was Cantleave made the suggestion to visit this thread, of course it was you! I'm up to page 5 now. I just don't want to be totally ignorant on what 'evolutionists' believe.
I think I can understand in a limited way the processes involved as you are trying to explain them. However from my point of view I still don't see how it negates a creator at the beginning, or even during each of those processes. I'm still of the firm belief in intelligent design.
I guess when it comes to the divide between man and apes (as well as all other animals), to me it's the differences rather than the similarities that cause me to believe in an intelligent designer. Man's spirituality for instance and I don't just mean his 'need' to 'worship' something.
His capabilty of complex languages, some people being able to understand several. His creative abilties, the millions of things that man has created himself. His inbuilt morality. His love of beauty, whether it is appreciating a beautiful landscape, a flower, a piece of music or art. His abilty to express himself in music, in composing it, being able to understand rythm, harmony and melody and putting it together with or without lyrics. His understanding of history and how he fits into it and being able to project into the future. His being able to unravel and comprehend science.
I know my words are not as eloquent as yours and my understanding of science is relatively small but to me these are things I don't think science could explain to me.
Well done on making the effort to understand evolution tornapart.
I think its important to divide the science from the philosophy. Science can prove our physical descent from non-human ancestors, that much is beyond dispute.
It can't prove that there is no god - although it can show that there is no need for the supernatural to explain the world. Naturalism works.
Intelligent Design asserts that certain features of the natural world are too complex to evolve through natural processes. This has been shown to be false. The work of Behe & co has been shown to be unscientific creationism.
As for human "spirituality" the field of neuroscience is using powerful imaging techniques to show that our brain and our mind are one and the same. Its a fascinating field of research that I would like to know more about.
Science has a lot of work still to do but resorting to supernatural answers is to opt out of the process of discovery.
I'm not sure I would agree with your last statement Cofty but I do understand how in certain cases that can happen. Science is making new discoveries all the time and it seems that the more discoveries are made the more questions are brought up.
Religion has made people closed minded to anything (as we've discovered to our cost), so I think it's important to keep asking questions. If something just doesn't add up you have to try looking at it in a new way, whatever it is.
I must say you've explained things in a very clear and understandable way and I really respect you for the manner you've done it. It goes a long way to encourage 'believers' to at least have a look at it.
And speaking of predators and prey...there is a reason both are very fast. Both have evolved to either chase and kill...or run and get away. Without the predator...the gazelle may have had more benefit in some other area of evolution instead of investing so many of its resources in speed. Maybe they would develop long necks if they had time to stand around eating leaves off trees.
Actually, neither evolved to chase and kill ( or run and not get killed) according to what you wrote previously.
Accoring to that, they happened to get "fast" and use that speed to either run and kill or runaway and n ot get killed.
It seems what is being said is that mutations just happen ( either by radiation or certain environment factors) and then the animal USES those the natural selection as shown to be most benefitial for it.
Is that the jist of the theory?
Yes Psac you are right.
We use misleading shorthand a lot.
Many people who think they get evolution are actually Lamarckian in their thinking.
To complicate things furhter the field of epigenetics is revealing how environment may effect which genes get switched on.
It is my understanding though that not everyone agrees that mutations come first and then the animal benefits from whichever ones are best suited to it.
I think there is some "disagreement" on this no?
I have read views that if the environment is what cause the mutation, then the mutation will be, eventually, because of the environment, an answer to it.
I understand that most suggest that mutations are NOT directed by outside forces, but simply happen because of them, but aren't we disregarding the fact that without outside sources there woule be no mutation or evolution? And IF that be the case how can we categoricaly state that mutations are NOT directed bu outside sources?
not everyone agrees that mutations come first
Yes everybody agrees.
aren't we disregarding the fact that without outside sources there woule be no mutation or evolution?
No. Mutations are random events.
Every one of us have unique mutations that were a result of simple copying errors.
I don't know what you have been reading but it wasn't written by a scientist.
I am not saying that mutations AREN'T random, I am saying that the cause of mutations could lead the mutation to be of a specififc nature, no?
I am asking how much influence does what causes a mutation to happen, have on the mutation?
Feb. 10, 2012 — Advances in studying genes mean that scientists in evolutionary developmental biology or "evo-devo" can now explain more clearly than ever before how bats got wings, the turtle got its shell and blind cave fish lost their eyes, says University of Massachusetts Amherst evolutionary biologist Craig Albertson.
He recently won a five-year, $625,000 Faculty Early Career Development grant from the National Science Foundation (NSF) to study the evo-devo of jaws in cichlid fish, tropical freshwater relatives of the tilapia. These highly adaptable cousins of sunfish, usually medium-sized and looking a bit like perch, have a phenomenal ability to undergo evolutionary change. They've developed 1,000 new species in Lake Malawi, Africa, over the past million years, a far faster pace than usual for other vertebrates in a similar period.
The NSF grant is the foundation's most prestigious award in support of junior faculty who exemplify the role of teacher-scholars through outstanding research, excellent education and the integration of both.
Through evo-devo studies, scientists now know that much biodiversity is due not only to differences in genes, but to changes in how and when genes are expressed, says Albertson. They also now recognize that genes interact with each other and the environment in development to determine phenotype, or an animal's observable traits.
"This carries Charles Darwin's ideas forward to a new level, to previously unconsidered sources of variation that can affect the evolution of traits. One in particular is phenotypic plasticity, the idea that different patterns of variation will be produced in different environments," Albertson says.
He chose to study evo-devo in cichlid fish because "they're obviously doing something right, from an evolutionary perspective, in a very dynamic environment, Africa's Rift Valley." Lake Malawi water levels have fluctuated up to 300 meters in the past 2 million years, providing everything from clear fresh water to an oxygen-poor soup high in salt, alkali or sediment, for example, but cichlids continue to adapt and survive.
Jaws are a good marker of adaptation because they are linked to survival, and the jaws of Lake Malawi cichlids can change rapidly to take advantage of new food resources. For example, open-water feeders have long jaws to snatch free-swimming, mobile prey, while bottom-feeders tend to have short, stout jaws for scraping algae from rocks. It is clear that these differences in jaw type are genetically determined, but Albertson wants to find out how much is also determined by the environment.
In studies he started at Syracuse University before coming to UMass Amherst in 2011, Albertson and colleagues are working to identify the set of genes responsible for determining jaw shape in both "normal" and "extreme" environments. They are taking a genetic mapping approach, using hybrids from a cross between two species differing subtly in jaw length. To begin, they raised an initial group of hybrids on an algae-based flake food, which is very easy for the fish to eat, Albertson explains. This population will be used to map genetic determinants of jaw shape under "normal" conditions.
Next, the biologists split the resulting hybrid families and reared them on two different diets, an algae-based diet spread on lava rocks, requiring fish to scrape to feed. These fish developed shorter jaws to accomplish this. The other treatment involved the same food, this time ground and sprinkled on the water surface. These fish had to suck food out of the water column; they developed longer jaws as they became more efficient at this task.
As Albertson explains, "The idea is that these two conditions should be similar to those in early Lake Malawi, when fish first arrived from surrounding rivers. Presumably the ancestors of Lake Malawi cichlids all looked the same, but some went up to suction feed while others went down to scrape, and plasticity produced fish with different jaw lengths. By re-creating this scenario and mapping the genes that underlie these environmentally induced shape differences, we hope to learn about the genetic interactions that were the first step in producing the 1,000-plus species in the lake today."
One key question he and his colleagues want to answer is whether the same set of genes are involved in developing crushing jaws and sucking jaws under normal and extreme environments. "We don't know if patterns of plasticity will affect patterns of evolution. We may see a different genetic response to distinct mechanical stimuli. But if we do recover a common set of genes under both normal and extreme conditions, it would substantiate key theories with respect to plasticity's role in evolutionary change."
Albertson also plans to reach out to high school science teachers with workshops to offer new perspectives on genetics and evolution. "Evolution has been taught largely the same way for decades now," he says. "But today evo-devo has produced a much more detailed understanding and appreciation for fine points of evolution. We now know, for example, the genetic and developmental processes responsible for how the bat got its wings and how the whale lost its hind limbs. These are compelling examples of evolutionary change that should resonate with students. It is a really exciting time to be an evolutionary biologist!"
