buy canada goose jacket Texas blind salamander has optic nerves but no real eyes Why Evolution Is True buy canada goose jacket
canada goose coats Straight talk about Islam in the Los Angeles TimesThis is the kind of post I originally intended to go on this site. When I started this website, I thought that every few weeks I publish a bit of new (or old) evidence for evolution, supporting Why Evolution Is True, which was a new book in 2009. Well, canada goose outlet uk sale as you see, things kind of got out of hand… It also lostpigmentation, as is the case for many cave dwellers. Finally, it its canada goose outlet new york city distribution limited to the Balcones Escarpment near San Marcos, Hays County, Texas You can find this animal only in the green area below; it been listed as canada goose outlet us endangered since 1967. Fish and Wildlife Service (USFWS) notes: canada goose coats
The Texas blind salamander has been canada goose parka outlet listed as endangered since 1967. It remains vulnerable, says San Marcos ARC director, Dr. Ken Ostrand. “They are impossible for scientists to sample canada goose outlet in uk underground, so we collect them in nets when they pop out in wells and springs, young ones, too small to fight currents,” said Ostrand. The young go into captivity at San Marcos ARC where they are held in refugia as a guard against potential harm that could come in the wild. Ostrand says their habitats, which he describes as a ‘limestone honey combed sponge,’ are quick to recharge canada goose outlet online store review with canada goose jacket outlet store surface precipitation, which could be accidentally laden with unwanted chemicals or spills. Preserving Texas blind salamanders in captivity is a security measure.
Canada Goose online The USFWShas just put out an information sheet about the species, first discovered in the 1890s, canada goose outlet ontario giving notes about its morphology, behavior, and adding that 135 of these beasts are being kept at the San Marcos Aquatic Resources Center. Canada Goose online
canadian goose jacket What relevant for our purposes is the salamander eyes, which appear to be small black dots of pigment canada goose outlet online reviews below the skin, accompanied bya vestigial optic nerve that doesn appear to canada goose outlet uk carry any impulses to the brain. As the USFWS notes: canadian goose jacket
canada goose clearance Recent research on the salamander has canada goose outlet store montreal yielded other useful information. San Marcos ARC scientists collaborated with Texas State University faculty on a study of eye development in the Texas blind salamander and two other salamander species that live in the Guadalupe watershed: the San Marcos salamander and Barton Springs salamander, both of which are sighted animals that live near sunlight. Both are held in refugium at the ARC as canada goose outlet trillium parka black well. canada goose clearance
canada goose factory sale The research revealed that the blind salamanders retained a vestigial optic nerve with no eyes while the other species had well developed eyes with structures for focus and variable light adaptation. The findings will be canada goose stockists uk published in a peer reviewed scientific journal, and have already yielded a master’s thesis. canada goose factory sale
Canada Goose Online It hard canada goose outlet eu to imagine anything but evolution that would explain the presence of these vestigial eyes and nerves. Canada Goose Online
The last one has no visible eyespots at all. Now I could write some more about eye loss and howitgives evidence for evolution, but I ask you, the readers, to answer two questions:
If you were a creationist trying to show canada goose outlet online uk that the vestigial eyes werenot evidence for evolution, what would you say? I can think of at least three responses.
Assuming, as is certainly the case, that the eyes have become vestigial via evolutionary processes, how do you think it canada goose outlet canada happened? We don know for sure, of course, but I can think of at least three ways.
uk canada goose outlet Put your answers below; there is no prize save the joy of thinking. uk canada goose outlet
buy canada goose jacket cheap Yes. It well known that the brain is a very expensive organ, in terms of calories, blood supply, and so on. It kind of follows that neurons are expensive. In total darkness, any mutation that selected for no eyes and the associated neurons would be advantageous, given no other canada goose outlet store toronto very harmful effects. buy canada goose jacket cheap
It appears to me that these salamanders are a transitional species, and that given time the optic nerves would disappear entirely.
canada goose uk shop It would be interesting to know if canada goose outlet near me they could adapt to a lighted environment canada goose outlet winnipeg address by redeveloping eyes. The genes are still be there in the population, but turned off. It telling that there a large variation in the development of vestigial eyes. canada goose uk shop
cheap Canada Goose 1) For question 2, in the absence of persistent selection to maintain vision, alleles needed for eye form and function could have been lost by genetic drift, particularly since these animals are likely to have been in chronically small populations? Mutations could have freely accumulated that altered eye development. cheap Canada Goose
Canada Goose Jackets 2) There could be some small resource to not producing eyes, canada goose outlet london https://www.canadagoosestorevip.com uk so there could have been direct selection for reduced investment in eyes and allocation to other needs. Canada Goose Jackets
canada goose coats on sale 3) In the cave environment, eyes could have been a directly detrimental trait canada goose outlet mississauga sources of infection canada goose outlet houston so that again, with no need of vision selection could play a role in reducing them. canada goose coats on sale
Canada Goose Coats On Sale 4) (doubtful) Loss of eyes could be a pleiotropic response to changes in other traits in response to the cave environment, again in the absence of selection for maintaining them. Canada Goose Coats On Sale
canada goose uk black friday I wish I could have gotten a pic but cave humidity canada goose kensington parka uk requires a special camera set up for decent shots that aren’t fogged up with steam from your body. canada goose uk black friday
canada goose black friday sale Well, technique, but not a lot of dedicated kit, unless you count the ammo box for getting the camera down t and still working. canada goose black friday sale
I never been terribly successful with cave photography, but my dad does (did) a fair bit more. Essentials are a camera with a exposure setting, and assistants who can sit quietly in the dark and take instruction to let off their flashes on cue. Slave flash triggers are a useful addition, but technique is more important. Specifically to let the steam dissipate. Getting the flash metres away from the optical axis of the camera is another canada goose outlet 80 off standard technique. Since you got indefinitely large supplies canada goose outlet of dark, you don need to muck around with synchronising the shutter and the flash.
canada goose store I saw the kit used by another member of our group, and it was far more complex and professional than I could ever use or afford, but yes, I get what you are saying. However, at the time, I didn even own an iPhone. Had I owned solid waterproof camera I would have attempted some pics, but even that was a bit out of reach for me (I did have access to an ancient Pentax but that wouldn have survived the water, mud, muck, and belly crawls). I suppose I should have prefaced the statement with the fact that, through my own failures and issues, canada goose outlet florida I been a member of the working poor single parent brigade for the last 18 years, so pretty much anything canada goose outlet in new york was out of financial reach. But if you keep you eyes peeled on diving websites, they not as eye watering as a Nikonos canada goose store.