Discussion Topic |
|
This thread has been locked |
BASE104
Social climber
An Oil Field
|
|
|
Jul 29, 2015 - 12:00pm PT
|
From the OP:
1. Are humans still evolving? I mean significantly. Are we going to continue evolving bigger brains for instance. Since natural selection requires some sort of selection pressure, typically involving either a significant culling or isolation of a population, is this likely in a world of 7 billion where people move (and procreate) freely across the planet?
Of course we are changing, and that is all that evolution means: change.
Many inheritable diseases can be treated now, so the afflicted can have children and pass on the defect. There might be "positive" evolutionary processes going on, but I doubt it. Anyone can have children. It has nothing to do with economic or physical success. Anyone can mate now, and their progeny has an excellent chance of surviving to adulthood.
Perhaps women, when choosing a mate, consciously or unconsciously seek out good genetic qualities in their men. I'm sure that this is going on to some extent, but how important or common it is, I dunno.
2. Is group selection, as advocated most notably by the evolutionary biologist E.O. Wilson, a viable process for explaining things like altruism or can this be explained entirely by selection at the organism or gene level?
Humans are very altruistic. This has probably been burned into our genes for millions of years, back to the more primitive primates. Lots of animals cooperate, sometimes while hunting or feeding, and we can see it all around us in our behavior. The only exception is our tribalism, which also seems hereditary. We view other tribes as enemies and have wars, discrimination, and the like.
We all inhabit this small blue planet, but a look at a map will show a large number of nations, or tribes. Each has its own agenda for survival, and this leads to things like war. If we could only get rid of that, the species would have a better chance. Now we have enough nuclear weapons to destroy ourselves. It is a miracle that we haven't had a nuclear war somewhere in the world. Now some of the tribes have the ability to totally destroy their rivals. Destroying themselves in the process. The only reason to launch a nuclear counter strike is simply a sting back. That hangs over us like a sword.
3. What is the likelihood that the emergence of life on a planet will lead to intelligent life given 100s of millions or billions of years of evolution to work with.
This is really a tough one. We know that life began on Earth as soon as it had cooled enough to be habitable by life. We only have a sample of one, but using it, it seems that life is pretty easy to start.
Despite that, life hung around as single celled organisms for billions of years. It took the Cambrian Explosion, only 550 million years or so ago, to bring complex, multicellular life. So complex life took a long time to happen. This could mean that much life elsewhere is simple. They may not have had a Cambrian Explosion on most planets.
So..from our sample of one, simple life seems to happen easily. Complex life is probably much rarer, and intelligent species like ours has taken hundreds of millions of years to arise since the Cambrian Explosion. We have been around for almost 2 million years, but it took us most of that time to move beyond stone tools. Native Americans used stone tools. They had no metallurgy, but the middle east did, and it spread to Europe.
We are seeing an explosion in technology. 10,000 years ago we were using the same stone tools that go back over 3 million years. Prior hominid species were using stone tools.
Anyway, look at today, then stop and consider how quickly things have happened. Homo Sapiens has totally altered nearly every inch of the Earth, and if he were so inclined, could.
This is new.
|
|
BASE104
Social climber
An Oil Field
|
|
|
Jul 29, 2015 - 03:13pm PT
|
DMT, the only real thing that matters is passing on your DNA. If you can survive long enough to do that, you win.
Nature has differing methods. Some species compete, like bull elk fighting during the rut. With others it is a simple orgy.
|
|
BASE104
Social climber
An Oil Field
|
|
|
Jul 29, 2015 - 03:40pm PT
|
I saw something really interesting the other day. Science Channel probably. It runs in the other room while I work.
This company not only does in-vitro fertilization, but they let the embryo grow to a small amount. 32 cells or so.
They take one of the cells from each egg and then run their genomes through a database looking for known genetic diseases.
They then pick the best egg and implant that one in the mother. It is expensive, but you can screen for certain genetic diseases. A woman was using it to make sure that she didn't pass on her breast cancer gene.
This has all sorts of implications, and I would bet that we will see them in the next 20 years. Our evolution will happen in a lab, and there might even be a higher class of human created, much like the film, Gattica.
Boy does that raise a lot of ethical questions. Imagine genetically engineered humans. It will almost certainly happen if we don't blow ourselves up first.
|
|
High Fructose Corn Spirit
Gym climber
|
|
|
Jul 29, 2015 - 06:26pm PT
|
I too saw the piece to which your post referred.
I agree with your post.
Regarding eugenics 21st century style (cf: eugenics early 20th century German and American styles), it's too powerful to stop.
Ultimately it's power, combined with other powers, will probably save us, I think.
I wish we could all be born again - as these are very exciting times indeed. Unfortunately, like C Hitchens, we of this generation are all going to be told sooner or later it is time to leave the party and are going to be shown the door. :(
|
|
Craig Fry
Trad climber
So Cal.
|
|
|
Aug 12, 2015 - 09:43am PT
|
Freaky
science is better than fiction
and way better than imaginary gods somehow pulling all the strings
If God is pulling any strings, shouldn't science be able to investigate and discover how he does it?
Why would it be hidden?
|
|
BLUEBLOCR
Social climber
joshua tree
|
|
|
Aug 12, 2015 - 08:57pm PT
|
He's not hiding
You just don't know how to look
You prolly got vertical pupils.
|
|
Ed Hartouni
Trad climber
Livermore, CA
|
|
|
Apr 30, 2016 - 10:10am PT
|
back from The Creek and some real-time camp-fire talk... after climbing...
eeyonkee and Moosedrool were discussing the book 40 Years of Evolution: Darwin's Finches on Daphne Major Island (at least I think they were, I was helping with dinner prep). This discussion spilled over and the speculation of what DNA analysis might be useful in understanding the apparently rapid adaptations was floated, I think this was a breakfast/coffee conversation.
Anyway, my paper copy of Science arrives about a week after the issues release, but having the entire issue at hand means I read most of the articles... and interestingly, this article appeared:
Science 22 Apr 2016:
Vol. 352, Issue 6284, pp. 470-474
DOI: 10.1126/science.aad8786
A beak size locus in Darwin’s finches facilitated character displacement during a drought
Sangeet Lamichhaney, Fan Han, Jonas Berglund, Chao Wang, Markus Sällman Almén, Matthew T. Webster, B. Rosemary Grant, Peter R. Grant, Leif Andersson
Abstract
Ecological character displacement is a process of morphological divergence that reduces competition for limited resources. We used genomic analysis to investigate the genetic basis of a documented character displacement event in Darwin’s finches on Daphne Major in the Galápagos Islands: The medium ground finch diverged from its competitor, the large ground finch, during a severe drought. We discovered a genomic region containing the HMGA2 gene that varies systematically among Darwin’s finch species with different beak sizes. Two haplotypes that diverged early in the radiation were involved in the character displacement event: Genotypes associated with large beak size were at a strong selective disadvantage in medium ground finches (selection coefficient s = 0.59). Thus, a major locus has apparently facilitated a rapid ecological diversification in the adaptive radiation of Darwin’s finches.
Similar species potentially compete for limited resources when they encounter each other through a change in geographical ranges. As a result of resource competition, they may diverge in traits associated with exploiting these resources (1, 2). Darwin proposed this as the principle of character divergence [now known as ecological character displacement (3, 4)], a process invoked as an important mechanism in the assembly of complex ecological communities (5, 6). It is also an important component of models of speciation (6, 7). However, it has been difficult to obtain unequivocal evidence for ecological character displacement in nature (8, 9). The medium ground finch (Geospiza fortis) and large ground finch (G. magnirostris) on the small island of Daphne Major provide one example where rigorous criteria have been met (10). Beak sizes diverged as a result of a selective disadvantage to medium ground finches with large beaks when food availability declined through competition with large ground finches during a severe drought in 2004–2005 (11).
.
.
.
Our results provide evidence of two loci with major effects on beak morphology across Darwin’s finches. ALX1, a transcription factor gene, has been associated with beak shape (15), and here we find that HMGA2 is associated with beak size. ALX1 and HMGA2 are 7.5 Mb apart on chromosome 1 in chicken and zebra finch, and probably also in Darwin’s finches, as expected on the basis of the very high degree of conserved synteny among birds (24). Beak size and beak shape are involved in all the major evolutionary shifts in the adaptive radiation of Darwin’s finches (1). They are also subject to strong selection in contemporary time. In the character displacement episode discussed above, beak size was subject to strong directional selection: The standardized selection differential of –0.66 for sexes combined is an exceptionally high value. We have shown that the HMGA2 locus played a critical role in this character shift. The selection coefficient at the HMGA2 locus (s = 0.59 ± 0.14) is comparable in magnitude to the selection differential on the phenotype and is higher than other examples of strong selection, such as loci associated with coat color in mice (s < 0.42) (25). The main implication of our findings is that a single locus facilitates rapid diversification. The lack of recombination between the two HMGA2 haplotypes, together with abundant polygenic variation and ecological opportunity (2, 5), may help to explain rapid speciation in this young adaptive radiation (1).
|
|
TLP
climber
|
|
|
Apr 30, 2016 - 11:15am PT
|
BASE wrote:
Anyway, look at today, then stop and consider how quickly things have happened. Homo Sapiens has totally altered nearly every inch of the Earth, and if he were so inclined, could.
This is new.
I always enjoy his geological perspectives and informative posts, but I have to disagree on that one point. When land plants expanded hugely in biomass, they photosynthesized like crazy and completely poisoned the entire atmosphere of the planet with oxygen, which is incredibly toxic to many species. He'll know exactly, but it went from some fraction of a percent or a few percent right up to 10 and then 20 percent really quickly (geologically speaking). So while it may be new for just one single species to have effected such a big change, the phenomenon is not unprecedented. Changes in physical environment are frequent causes of species evolution, but it can happen the other way around too.
Luckily enough for some clades of organisms, they could use the stuff and quickly diversified and expanded into every niche.... and some of them ultimate became humans and set about trashing the land and ocean environments.
|
|
eeyonkee
Trad climber
Golden, CO
|
|
|
Topic Author's Reply - Sep 9, 2016 - 12:51pm PT
|
Whoa, just saw this. Cool find, Ed! I've been reading a great new book, Why Evolution is True, by Jerry A. Coyne. It has a chapter on seeing evolution in action, that includes some cool experiments of this nature. Nothing like seeing it on video.
By the way, that sh#t is pretty scary! Underscores how we will always have our work cut out for us as humans to stay ahead of bacteria and viruses that would do us harm.
|
|
|
SuperTopo on the Web
|
Let us know!