The Science of Speciation – Molecular Adaptation in Vampire Bats


“You can smell the ammonia as soon as you come in.” “See them? Neat, eh?” “Yeah. Those are vampire bats?” “These are vampire bats, yeah.” Nancy Simmons (AMNH):
There are 1,300 living species of bats. That is about 20% to 22% of all living mammals. “It’s this one here.” “Oh-ho, there’s a bat.” We think that the great diversity of bats
has to do with the fact that they occupy a really unusual niche for a mammal. That is, a nocturnal-flying-mammal niche. “Beautiful.” So, you have some roosting high up in trees. Others close to the ground. “Bugger!” And different bats eating different kinds
of things – nectar feeders, fruit feeders, carnivores, insectivores, and even
blood-feeding bats, the vampires. “Hi, sweetheart.” I’m an evolutionary biologist, interested
in the evolution of diversity in body form of mammals, diets of mammals,
species diversity of mammals. And bats are just a wonderful group to work on, because they’re so diverse, so interesting, and they do so many different things. [forest sounds, footsteps] [Lamanai Archeological Reserve – Belize] A typical night of catching bats begins at about five o’clock. We need to give ourselves an hour,
hour and a half, to get everything situated before the bats wake up. [music, forest night sounds] “Oh, we got a fourth.” “Nope, it got out. Spoke too soon.” Bats can be told
apart with a variety of different traits. The size and shape of the nose leaf
varies from one species to another. “What was there?” “The vampire bat.” There are bats that
have stripes above and below their eyes. Shape of the ears can vary. “This is a little-nectar feeding bat. It has a long tongue
that it can put inside flowers.” So, just looking at the outside of the bat
you can tell a great deal about what species it might be. “Here you go. Desmodus rotundus.” “Need help?” “Nope, I’m fine. “Ah, that’s that standard vampire sound.” Toni Piaggio (USDA):
There are three species of vampire bats: the hairy-legged, the white-tipped,
and the common vampire bat. In this portion of Belize, we only find the
common vampire bat. “Don’t want him to flip onto
my naked hand.” The three species all feed on blood, but the hairy-legged bat only feeds on bird blood. The white-tipped bat feeds on bird blood,
and there have been records of them feeding on mammalian blood. But the common vampire bat
specializes on feeding on mammals. “Do not want to be tangled up in there. There we go, now you’re looking photogenic.” “Nice mug.” We don’t entirely understand why there are three vampire bat species, what kind of diversification has happened there. And so, using molecular biology, sequencing
DNA, we can really get at this question. [music] David Liberles (Temple University):
A long-standing goal in molecular evolution is to understand which are the changes in individual genes that have made each species unique. So, my research group has undertaken a large-scale
screen of genes that are candidates for having undergone positive selection. One of the genes that we came across was the gene for plasminogen activator in vampire bats. All organisms have what’s called plasminogen
activator, which is active in their tissues and plays an important role in maintaining
blood flow throughout the body. In vampire bats, adaptive changes have enabled
them to express the activator in their saliva. So, when they bite an animal, it helps to
keep blood flowing, allowing the vampire to keep feeding. “So, here we are at the vampire bats and
we’ve separated out the bat activator…” When we look at changes in individual genes,
we’re ultimately asking how does it affect the fitness of the organism – the probability
of surviving, of finding a mate, and of reproducing. And so, this is the biological currency in
which evolution works. When we think about things like blood feeding,
if you’re able to get a new food source and to reproduce faster, then that’s increasing
your fitness and makes you more likely to survive, more likely to reproduce. “So, plasminogen activator is a crucial
promoter of breaking up blood clots. Within vampire bats…” When we started this work, the idea that there
were changes to this gene in vampire bats was already known to science. However, it was not known how this related
to the blood-feeding behavior of different vampire bat species. When we compared the genes of the three species,
we found that they were different. While the hairy-legged vampire, which feeds
on bird blood, had a normal activator, a modification to the gene in the white-winged and common
vampire bat appeared to be related to the ability to feed on the blood of mammals. Mammals have a mechanism that enables them
to shut off the activator when bleeding becomes dangerous,
allowing blood to clot. The change that we found in the white-winged
and common vampire bat enables them to override this clotting mechanism and keep blood flowing
in mammals they bite. [music] Once we’ve sequenced a gene, we can build a gene tree reflecting the evolution of that gene. We can then take that gene tree and correlate
it with the species tree, adding discoveries of genetic changes within that species. “So, I think this is actually an elegans. See how the knees are naked?” Everything that we observe in how a species
interacts with its environment will have some basis, at some level, in genetics. And so, understanding the genetic processes
that give rise to how species are different, and how they interact differently with the
environment, is a fundamental scientific question that enables us to understand species in general. [Simmons] The age of genomics has just opened up so many new areas for research. We’re able to answer questions that in the
past biologists would have liked to know the answers to, but there were no tools. So basically, it’s a whole new toolkit that
lets us address all kinds of interesting biological questions
that we just couldn’t get at before.

6 thoughts on “The Science of Speciation – Molecular Adaptation in Vampire Bats

  1. Just friggin' awesome! So vampire bats have been around so long that their initial choice of prey was a direct descendant of the dinosaurs. They evolved to target mammals one mutation at a time each one slightly increasing the capacity to target a growing food source.

  2. Hold up, did Nancy just say bat species account for 1/5 of all mammal species? And then the video moved right along like that's not a shocking claim?

  3. We are told over and over and over that a new species shows evolution. Nope. Speciation (the creation of new species) does not support evolution as it is an example of stasis and stasis is the exact opposite of evolution. For ex. over 200,000 species of beetles are all still beetles. That's stasis. There are thousands upon thousands of species of birds, bees, lizards, trees, bacteria, trees, yeast, flowers, whatever. If a new species develops within any groups at all, you can bet your bottom science dollar that it will still be just a beetle, bee, bacteria, tree, fish, finch or whatever. That's stasis, not evolution.
    .
    We are supposed to fill in the blanks here with…faith…and think, "Well! If a new species develops then things just keep evolving and evolving from there on." But the next step above a species, in the animal or plant kingdom, is a family. (A genus is just a grouping of similar species together). We aren't seeing any new families – much less any new order, class, phylum or kingdom – forming. Anywhere. Ever. According to Darwin's so called Tree of Life and peer reviewed evolutionary literature, new families have evolved. Over and over and over. Not just new families are claimed, but also the creation of new orders, classes, phyla.
    .
    However, nature operates today as it did in the past. In the real world, with trillions of life forms around us, we never see anything developing above the level of a new species. Those life forms out there have purportedly had eons and eons of ancestors preceding them which should be revealing at least one example of a part this family "transitioning" to be a part that of another family. Again, we see stasis.
    .
    We only see "transitions" to those higher levels in the purely theoretical, unverifiable, ancient past, in the realm of evolutionary literature, and never in any life around us. If there is no evidence for transitions from one family to another – and please provide data if you know of any such evidence in the observable and not theoretical realm – then there is no evidence for evolution. It's that simple. And that's just for starters on how evolutionism defies real science.
    .
    Anyone: Kindly don't say some fossil provides the evidence. It is easy to point to a pile of petrified bones and make up stories about how its invsible and evidence- free descendants turned into some other life form. But if you insist, use a fossil. Name it. Then tell how you know it even had a descendant, much less one significantly different from it, much less one that crossed the family barrier. Name the family it is transitioning out of and the one it is transitioning into.
    .
    Or, here's another chance to support evolution with data. They say the two driving forces behind it are natural selection and beneficial mutations. Great. Name a life form. Tell what act of NS or what beneficial mutation is causing it to "evolve." Again, use real life forms. There are trillions out there. And we're told evolution is happening all the time. Remember, evolutionary poster kids like antibiotic resistant bacteria, walking stick bugs, some geckos, snowflake yeast, people with sickle cell anemia and so on show evolution is NOT happening. That's because they are all steadfastly staying bacteria, walking stick bugs, geckos, snowflake yeast and people. If not, what are they "evolving" into that doesn't fall into those categories? Cite your data.
    .
    But you will not. When evolution defending supporters on YT are asked to name a life form and then a mutation or act of NS that is causing it to evolve, they never do that. They may put down a glut of words, but there is no data in those words, whatsoever, provided for that request. When they are asked to name a life form that is moving from being more than just a new species into a new family (not to mention class, order or phylum), ditto. The most typical dodge seen to those quesstions is when they change the subject to something else.
    .
    And btw stasis is what the Bible predicts because it says creation of plants and animals has been halted. All we see now are those that multiply after their kind/family.
    .
    You are not a goo through the zoo update. You have a Heavenly Father Who made you in HIS image and likeness. He loves you and wants you to know Him, and to love Him, too. If you are an atheist and evolution believer, if you are anyone at all, He wants you to be His child. Forever. I know I found that out myself when I was an atheist and evolution believer who had never looked outside the box.

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