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WoodrowSkillson posted:What exactly confuses you about speciation? That sounds like a much more fun conversation to have then the one we had after the last episode! More of a hard time wrapping my head around the species problem more than speciation, I guess. But I know I'm not unique in that matter. It's pretty hard to picture when you stop having Wolf and start having Dog because there's this innate desire to compress the timescale so that you have Wolf --> Wolf-Dog --> Dog. Like...at what point did you get an animal that can't breed back up the branch, so to speak. Is it a matter of a slow burn where you have animals less likely to produce fertile offspring? My science is all space stuff, so biology baffles me beyond all comprehension. Not even making sense out of astrobiology. Decided to be a water and carbon chauvinist and called it a day. DarkCrawler posted:Don't we have a bunch of useless poo poo leftover from previous species we evolved from? The appendix, tailbone, etc. I thought they recently determined the appendix did something. Also, the tailbone serves the vital role of having a hilarious bone to break, because coccyx is fun to say.
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Mar 17, 2014 21:01
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DarkCrawler posted:Don't we have a bunch of useless poo poo leftover from previous species we evolved from? The appendix, tailbone, etc. We get goosebumps when freaked out because of a vestigial adrenal response which is supposed to cause all our fur to stand up.
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Mar 17, 2014 21:03
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DarkCrawler posted:Don't we have a bunch of useless poo poo leftover from previous species we evolved from? The appendix, tailbone, etc. http://scienceblogs.com/grrlscientist/2010/06/22/the-laryngeal-nerve-of-the-gir/ the laryngeal nerve is the best example of this kind of stuff. In humans and other smaller animals, it does a short loops around the heart that is a little inefficient but whatever. In the giraffe its huge and unwieldy for no good reason other then it evolved from a creature with the normal nerve and had to make do with it, since a mutation that redoes it will also break the ability of it to work.
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Mar 17, 2014 21:05
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DarkCrawler posted:Don't we have a bunch of useless poo poo leftover from previous species we evolved from? The appendix, tailbone, etc. Here's NDT on the stupid design of the universe in general and humans in particular. https://www.youtube.com/watch?v=4238NN8HMgQ
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Mar 17, 2014 21:05
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WoodrowSkillson posted:http://scienceblogs.com/grrlscientist/2010/06/22/the-laryngeal-nerve-of-the-gir/ The dumbest design flaw in humans (and all animals really) is probably how the air duct and the food duct intersect.
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Mar 17, 2014 21:08
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Sash! posted:More of a hard time wrapping my head around the species problem more than speciation, I guess. But I know I'm not unique in that matter. It's pretty hard to picture when you stop having Wolf and start having Dog because there's this innate desire to compress the timescale so that you have Wolf --> Wolf-Dog --> Dog. Like...at what point did you get an animal that can't breed back up the branch, so to speak. Is it a matter of a slow burn where you have animals less likely to produce fertile offspring? http://en.wikipedia.org/wiki/Ring_species http://evolution.berkeley.edu/evolibrary/article/0_0_0/devitt_02 Ring Species are a great illustration of the blurred lines inherent in speciation. Even though they all share a ton of genes, eventually enough changes that they cannot interbreed. The same kind of thing happens over time instead of distance. Species can be a nebulous concept, and behavior can lead to speciation as much as anything else. There are plenty of cases of species living alongside one another that can produce viable offspring but do not because they have the wrong mating colors or whatever, so the species are separate.
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Mar 17, 2014 21:14
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WoodrowSkillson posted:Dogs can still breed with wolves and have viable offspring. They are a separate species because outside of strange circumstances, they do not breed. I knew dogs and wolves could interbreed, so the whole time I was typing it, I was trying to think of two closely related species that weren't preposterous like "octopus" and "kangaroo." Is there anything that can breed outside of its genus? Or is genus a more clearly defined limit on breeding and less murky than species?
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Mar 17, 2014 21:22
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Atavistic, or old, "switched off" genes are pretty cool. We all have 'em from our ancestors. When you lose a genetic attribute (say, the tail) the gene for it doesn't just go away, but it gets switched off inside you so you don't grow one. Same with hair and certain other attributes. Sometimes that doesn't work and the gene stays on so you get kids born with tails and wolfboys with fur and what have you. Now the cool thing about atavistic genes is that if you can figure out which one does what, you could go in during the developmental stage and switch it on. They've done this with certain animals, chickens being one of the more famous examples of atavistic gene tweaking in utero; since chickens evolved from dinosaurs, they have dinosaurian atavistic genes for, say, razor sharp teeth, claws, and tails. And now we've made chickens with teeth, tails and actual claws instead of wings. Chickenosaurus.
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Mar 17, 2014 21:37
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Sash! posted:More of a hard time wrapping my head around the species problem more than speciation, I guess. But I know I'm not unique in that matter. It's pretty hard to picture when you stop having Wolf and start having Dog because there's this innate desire to compress the timescale so that you have Wolf --> Wolf-Dog --> Dog. Like...at what point did you get an animal that can't breed back up the branch, so to speak. Is it a matter of a slow burn where you have animals less likely to produce fertile offspring? I think the first point you make is the whole argument creationists like to pick on. The missing link between x and x. You can show off a fossil that's an in between stage of say a bird and a dinosaur, but then you create two missing link stages between that and the dinosaur and that and the bird. I believe the point has been made before that you can relate a fossil record of an evolution of species to a colour chart. The dinosaur is red, the bird is blue. There are many colors distinguishable in between, but at what point, when you look closer and scrutinize, does red become orange?
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Mar 17, 2014 21:56
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Stare-Out posted:Sometimes that doesn't work and the gene stays on so you get kids born with tails and wolfboys with fur and what have you. Now the cool thing about atavistic genes is that if you can figure out which one does what, you could go in during the developmental stage and switch it on. They've done this with certain animals, chickens being one of the more famous examples of atavistic gene tweaking in utero; since chickens evolved from dinosaurs, they have dinosaurian atavistic genes for, say, razor sharp teeth, claws, and tails. And now we've made chickens with teeth, tails and actual claws instead of wings. Chickenosaurus.
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Mar 17, 2014 22:12
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So, this episode made me look up how DNA evolved: I tried reading this and it was way too difficult for my layman's understanding of biology, but it was still fun to see just how complicated that issue is. Love the show and will be tuning in next week for sure!
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Mar 17, 2014 22:27
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achillesforever6 posted:Yep this is what Jack Horner wants to do. Jack Horner is completely insane, but drat it he helped consult Jurassic Park so he's okay in my book. He is nuts, but indeed his involvement in Jurassic Park scores him points and the guy is trying to bring back loving dinosaurs. That is cool as hell, crazy or no. His TED speech about the chickenosaurus sounds borderline frankensteinian but in an awesome way.
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Mar 17, 2014 22:52
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This site has some good reactions about the liberal atheist propaganda of Cosmos. http://aattp.org/right-wing-zealots-are-already-freaking-out-about-return-of-cosmos/
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Mar 17, 2014 23:27
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Mar 17, 2014 23:38
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Sqeetschy posted:So, this episode made me look up how DNA evolved I always found this idea fascinating: DNA replication is imperfect, which is the basis for random mutations in evolution. However, its possible that DNA replication WAS perfect initially, but it was naturally selected out to bring out the benefits of evolution. Its so meta!
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Mar 18, 2014 00:15
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FateFree posted:I always found this idea fascinating: That's not really plausible. Even engineered polymerases have an inherent error-rate. Biology is awesome, but it's not cut out for 6-sigma process efficiency
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Mar 18, 2014 00:19
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The broader point about the evolution of evolvability itself is a pretty hot topic, though. I don't know much about that area myself, but it's a cool idea that seems to get people fairly heated.
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Mar 18, 2014 00:23
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Trig Discipline posted:The broader point about the evolution of evolvability itself is a pretty hot topic, though. I don't know much about that area myself, but it's a cool idea that seems to get people fairly heated. Soon we will be determining the path of our own evolution in a precisely controlled manner, and this is incredible.
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Mar 18, 2014 00:29
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Sash! posted:I knew dogs and wolves could interbreed, so the whole time I was typing it, I was trying to think of two closely related species that weren't preposterous like "octopus" and "kangaroo." I think what you're looking for is when horse and a donkey breed to make a mule. Horses have 64 chromosomes, donkeys have 62 and mules end up with 63 chromosomes. The resulting chromosomes work well enough to keep the mule living during normal replication, but overwhelmingly are screwed up enough to prevent the creation of eggs or sperm that can properly combine with its counterpart to create a new viable being. Now, there have been cases of mules that can procreate, which further supports the point: in those rare cases, a mutation occurs which allows it to happen.
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Mar 18, 2014 00:50
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Are Tigons or Ligers also sterile, or are they all just cats?
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Mar 18, 2014 00:51
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haveblue posted:Cat breeds don't make good examples of evolution because all cats are basically the same. Their fur is a different color or length, their facial features are slightly different, their temperament varies a bit, but they're all more or less interchangeable. You're not kidding. I only recently found out about all the different hybrids. It's amazing to think that African and South American species can still cross with each other. https://en.wikipedia.org/wiki/Felid_hybrid
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Mar 18, 2014 01:59
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AlliedBiscuit posted:FB friend from high school: "We're watching The first episode of Cosmos. They're talking about the origins of life on earth. The host says "we still don't know how life evolved". Is it wrong that I feel a huge sense of despair, anger, and sadness all at once when reading that?
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Mar 18, 2014 02:00
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Maldoror posted:Is it wrong that I feel a huge sense of despair, anger, and sadness all at once when reading that? Nope. That only means you're still sane.
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Mar 18, 2014 02:22
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Yaos posted:This site has some good reactions about the liberal atheist propaganda of Cosmos. Thank you. This thread was seriously not delivering what I was hoping for.
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Mar 18, 2014 03:06
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This last episode was fantastic. I'm really impressed by this show so far, and especially impressed that it's airing on Fox, of all places.
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Mar 18, 2014 05:16
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kant posted:Thank you. This thread was seriously not delivering what I was hoping for. I was actually going to say the opposite! I've learned more from this thread than the actual show, and that's awesome.
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Mar 18, 2014 05:24
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FateFree posted:I always found this idea fascinating: I think you might be interested in looking up theories like the 'RNA world' where the default is 'insane rates of evolution' and DNA taking over the inheritance properties of procreation is driven by the need for the stabilization of high inter-generational rates of change! (the rna world hypothesis is also helpful because it is one of our best ways of explaining the existence of things like viroids, cellular reliance on rna as an intermediate for many things, even though rna itself can retain functions on its own, and also, the answer to your question of how nucleic-acid replication used to happen initially - i.e. autonomously) Ernie. fucked around with this message at 05:33 on Mar 18, 2014 |
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Mar 18, 2014 05:29
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I had a thought about artificial selection... Isn't it very contrary to natural selection? Humans breed dogs for lots of dumb traits that actually hinder their survival chances, and keep them alive anyways in spite of the goals of natural selection. Dalmatians and pugs were bred for certain physical traits but have notorious health problems, but instead of weeding out the ones that would die left to their own devices, but we keep them alive I'm just sad about it because my mom had a pug with loads of health problems...
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Mar 18, 2014 05:30
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Steve Yun posted:I had a thought about artificial selection... Isn't it very contrary to natural selection? Humans breed dogs for lots of dumb traits that actually hinder their survival chances, and keep them alive anyways in spite of the goals of natural selection. Dalmatians and pugs were bred for certain physical traits but have notorious health problems, but instead of weeding out the ones that would die left to their own devices, but we keep them alive The BBC did a documentary called Pedigree Dogs Exposed that's worth looking up, it's all about that and it's incredibly heartbreaking. It turns out that when you breed based on the arbitrary physical traits of a breed standard you wind up with sick, deformed animals. Even healthy, working animals wind up bundles of cancer and dislocated hips over just 100 years or so. Also while the episode was airing people mentioned Belyaev's silver fox experiments, which are the inverse of that: they artificially selected animals based purely on behavioral traits and it has wide-ranging effects on their physical appearance in just a few generations. https://www.youtube.com/watch?v=0jFGNQScRNY
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Mar 18, 2014 05:37
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Could you imagine if aliens took us over and kept us as pets and started breeding us for arbitrary physical traits, what kind of horror show that would look like ? 
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Mar 18, 2014 05:46
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Steve Yun posted:Could you imagine if aliens took us over and kept us as pets and started breeding us for arbitrary physical traits, what kind of horror show that would look like ? https://www.youtube.com/watch?v=-9SSyjM9CPw https://www.youtube.com/watch?v=0dJCfzyxTEY 
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Mar 18, 2014 05:50
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Steve Yun posted:Could you imagine if aliens took us over and kept us as pets and started breeding us for arbitrary physical traits, what kind of horror show that would look like ? I'm having trouble finding the link, but I remember reading a few years ago on the BBC that human females have been selected for "arbitrary" physical traits over time, while men (who traditionally play a more functional role) have not. Anecdotally, you can kind of see it when you look at old photos and paintings. Heck, I remember seeing a contemporary bust of Cleopatra and thinking that history's grandest seductress looked plain...plain.
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Mar 18, 2014 06:36
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The most tell-tale evolutionary "feet" we humans are going through generation after generation right now is the further absence of the pinky toe. We are losing the little piggy that goes "wee wee wee!" all the way home but science seems to not give a gently caress about it.
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Mar 18, 2014 06:50
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Steve Yun posted:I had a thought about artificial selection... Isn't it very contrary to natural selection? It's contrary to survival in the wild, yes, but a purebred dog's environment isn't the wild. It's the human world, complete with reliable access to veterinary medicine, and the traits that lead to reproductive success are very different there. Having a flat face and trouble breathing and hosed up hips leads to the humans helping you to make more of yourself, so it's a viable strategy. haveblue fucked around with this message at 07:11 on Mar 18, 2014 |
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Mar 18, 2014 06:56
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Propaganda Machine posted:I'm having trouble finding the link, but I remember reading a few years ago on the BBC that human females have been selected for "arbitrary" physical traits over time, while men (who traditionally play a more functional role) have not. Anecdotally, you can kind of see it when you look at old photos and paintings. Heck, I remember seeing a contemporary bust of Cleopatra and thinking that history's grandest seductress looked plain...plain. A lot of people looked plain until like the 1920s though, it was probably more that a good diet is required to look (contemporarily) attractive.
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Mar 18, 2014 06:57
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Propaganda Machine posted:I'm having trouble finding the link, but I remember reading a few years ago on the BBC that human females have been selected for "arbitrary" physical traits over time, while men (who traditionally play a more functional role) have not. Anecdotally, you can kind of see it when you look at old photos and paintings. Heck, I remember seeing a contemporary bust of Cleopatra and thinking that history's grandest seductress looked plain...plain. You are using bad history. Cleopatra was, to contemporaries, known for not being that attractive physically. But, as Kissinger let us know, "power is super sexy." What she represented was much more attractive than any physical attributes. Historians made her out as a Helen 2.0 because that was the language of the time. Plus, suggesting that a women was desirable because of the power she represented really only had precedence with Gorgons. And what do you know? Critics compared her to those!
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Mar 18, 2014 07:03
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Evolution is the most fascinating thing. Endlessly fascinating. To me, it is on par with how something came from nothing. Find the answer to one, and you find the answer to both. Maybe.
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Mar 18, 2014 07:06
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Robnoxious posted:The most tell-tale evolutionary "feet" we humans are going through generation after generation right now is the further absence of the pinky toe. I've read that this is a myth. The real issue is, there's no reason why we would be losing our pinky toe. There's no survival driver for it. Pinky or no pinky, someone in today's society is going to live a normal life either way. Evolution doesn't eliminate useless bits of us if there's no advantage to doing so. If anything, I could see modern science and technology start to stagnate things a bit. I have severe congenital ptosis (drooping eyelids.) Without early surgery, my vision would have never developed normally and it would be extremely difficult for me to see anything because my eyes would be mostly closed. Hell, if I were born just 20 years earlier things would have turned out very different for me since the surgery I got as a toddler was cutting edge at the time. However, my ptosis now has no effect at all on my day to day life other than some minor eye irritation sometimes. 75 years ago and I probably would have been severely disabled. 500 years ago and I would have been effectively blind from birth which would probably negatively affect my chances of making it out of adolescence unless I was born into a wealthy family who could afford to take care of me full time. However, today, I'm free to pass that genetic defect on to my offspring where they will be even less affected by it due to further advances in science. There's still some culling of the genetic tree going on due to very severe genetic disorders, but there's a whole bunch of them now that get a free pass to the next generation because we've worked around them. Survival depends less and less on our genetics now, it will only be through direct manipulation that humans will reverse this pace. bull3964 fucked around with this message at 07:11 on Mar 18, 2014 |
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Mar 18, 2014 07:08
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It's really the opposite of stagnation - because certain traits aren't culled, there can be more genetic diversity because more variation is allowed to exist. Imagine all of the potential genetic diversity that would still be here if we hadn't had multiple events that wiped out 90% of all life on Earth.
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Mar 18, 2014 07:21
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computer parts posted:It's really the opposite of stagnation - because certain traits aren't culled, there can be more genetic diversity because more variation is allowed to exist. True, though I was thinking more along the lines of drastic changes down the line. We would have more minor genetic diversity, but no external driver to refine those traits (like the eye example) to something greater than the initial mutation. For example, we have people today that can see a FAR greater range of color, but there exists very little environmental driver for that to become a more widespread trait. It's a neat conversation piece and a scientific curiosity, but not something that affects survivability. bull3964 fucked around with this message at 07:29 on Mar 18, 2014 |
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Mar 18, 2014 07:26
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