In case you were wondering…
Geckos cling to glass via Van der Wahls forces between their highly ridged feet and their climbing surface. Without the aid of claws or sticky adhesive. Van der Wahl’s forces are weaker than those holding atoms together in a molecule, like ionic and covalent bonds. But! Gecko feet have such a high surface area, that with their powers combined…
Ta da!
Back to goat guts.
Once a goat has masticated a mouthful (preferably grass and NOT my hair), it travels down the esophagus into the forestomach. The forestomach consists of the first three compartments of the entire stomach, the rumen, the reticulum and the omasum. At this point the food is less food and more of a wet mass. Scientists call it a bolus, but in ruminants it tends to be called cud. As in the stuff they regurgitate to chew on. Anyway, the rumen and reticulum are quite large, most of the anaerobic bacterial fermentation occurs here, besides some absorption of simple molecules and nutrients. Furthermore, food can loop from rumen, to reticulum back to the mouth a couple times before it is digested enough to move on to the omasum. Non-food items (like my hair) will make this trip a quite a few times, assuming the goat does not eventually give up (unlikely) or realize that this particular bite is not terribly appetizing (hella unlikely). Anyway, this loop of repeated mastication, fermentation and absorption greatly increases the efficiency of digestion. If you’ve ever wondered why it’s harder for humans to be herbivores, among other things, our omnivore digestive tract is a LOT less efficient at tackling an exclusively plant-based diet. Our digestive tract is more like that of a carnivore, particularly in terms of length (proteins are much easier to digest so carnivore digestive tracts and relatively short).
Again, back to the goat guts. When the bolus/cud has been chewed for the last time, it heads straight for the omasum. Here water and more nutrients are absorbed via the omasum’s highly folded surface. Oh, and get this: the omasum SORTS shit. Seriously. Big stuff that needs more ruminating will get chucked back (and possibly up-chucked) for more digesting. Anything not turned back continues on to the abomasum. The abomasum secretes acids to digest proteins and rumen microbes (remember the NPCs? They need to stay put or they’ll cause an infection) before the bolus moves on to the intestine as gooey chyme. Nummers. If the digesting goat in question is a kid, the abomasum will also secrete rennin (cheese, anyone?) to clot casein (milk protein) for better digestion.
With the high appetizing chyme now safely in the intestine, I think most of you get the rest: highly folded small intestine continues to absorb water and nutrients, chyme gets denser as it is moved via peristaltic waves (muscles squeezing it down the line) to the large intestine for compression and eventual expulsion. Probably right when the goat’s yard has just been swept.
You guys are lucky you’re so cute.
Source
Sherwood, Lauralee, Hillar Klandorf and Paul Yancey. 2005. Animal Physiology: From Genes to Organisms. Thomson Brookes/Cole, Belmont, CA.
Photo credit, me.
OK, so goats.
I love goats. Not just itty kiddies, but grown ones too. Not sure why, they’re not usually terribly cuddly. Although if you scritch that spot on their backs, right between the hind legs they just go weak in the knees and it’s adorable.
Anyway, in high school I volunteered at the local zoo’s (Woodland Park Zoo) “Family Farm” which featured goats and other farm animals that are part of the summer petting zoo. Besides tidying their stables, etc., we were responsible for keeping the goats and sheep social in the winter so that when summer came they did not flip any shits over small children trying to pet them. Or at least in one goat’s case, make sure he continued to ignore/avoid everything (he was not actually in contact area at all, but we continued to dream).
So we got used to the goaty quirks, like chewing on our hair and coats. You would also notice them stand still, not moving then suddenly belch softly and start chewing, mouth abruptly full. If you think they just regurgitated something to continue chewing on it…you are exactly right. Goats are herbivores, and considering the low nutritional value of plants, and the high difficulty in digesting large quantities of plant fibers, they possess a stomach with four compartments with which they tackle their dinners. The biggest contribution to digestion in goats comes from bacteria. Bacteria actually aid in fermentation of ingesta (ingested food/miscelani). Though periodically the goats need to regurgitate things that require more chewing.
That’s just a little introduction, but I will continue tomorrow.
Source
Sherwood, Lauralee, Hillar Klandorf and Paul Yancey. 2005. Animal Physiology: From Genes to Organisms. Thomson Brookes/Cole, Belmont, CA.
Photo credit, me.
I would like to introduce you all to Bruno.
Bruno.
Bruno is an alligator snapping turtle. They are mostly aquatic (only females come to land for egg-laying) and live in the Southeastern US. The name comes from their thick, shield-like scales that resemble those on alligators. Bull shit. I think it’s cause those jaws COULD SNAP A GATOR IN HALF. Bruno could, anyway. But that’s just my opinion.
Better view of the gator scales on the tail and shell.
A small gator would actually make a nice meal for an alligator snapping turtle. They are carnivores and if you look inside Bruno’s mouth, you might see a little nubbin on his tongue. With increased blood flow, the nubbin expands and turns pink like a little worm, the turtle can then wiggle it around and attract prey straight into their mouth. Anything too big to fit gets torn apart into more manageable, bite-sized chunks. The turtles can hold very still for this, but will also hide in old catfish holes for extra camouflage. You’d think they could turtle up inside their shell to look like a rock, but their heads are so damn huge they won’t fit. The legs also don’t withdraw at all, so there’s that. Fun fact: there is a style of catfish fishing called noodling wherein the noodlers stick their hands into catfish holes for the toothless fish to bite onto, only to be yanked out and fried for dinner. Do you see where I’m going here? There are a lot of noodlers missing fingers out there. If Bruno is any indication, there are probably a couple lacking hands, too (hint: he is, average adult size range is 15.5-30.1 inches). Moral of the story: don’t put your hands or feet anywhere that you can’t see into. Also be glad there are too many Bruno-sized turtles out there. But he’s 250 lbs and well over 150 years old, so that’s not terribly likely. There are many more that are closer to this size out there:
Mini Bruno (most likely not his real name)
Both Bruno and Mini Bruno can be visited at the Wildlife Discovery Center in Lake Forest, Illinois (just outside Chicago, for you outsiders). I visited a couple years ago and loved it. Lots of herps with some raptors and a bobcat tossed in for good measure. They do quite a bit of rescue work and have obtained some of their animals in that way, Bruno included. Bruno had lived in a rusted-out tub that barely fit his shell (let alone his head and legs) for around 20 years before Rob Carmichael (curator of the Wildlife Discovery Center and turtle-holder in both photos) rescued Bruno and cleaned him up. No small feat considering Bruno was covered in a stubborn layer of rust and alligator snapping turtles are not exactly known for their sweet and gentle nature. But clean him up they did and now Bruno is happy as a large, gator-like clam, swimming around his tank at the WDC. Y’all should totally visit and say “hi”. Just don’t try to shake hands. That won’t go over well.
Source
Cogger, Harold G., Joseph Forshaw, Edwin Gould, George McKay and Richard G. Zweifel. 2002. “Turtles and Tortoises”. Encyclopedia of Animals. Barnes and Noble Books, New York.
Jackson, Tom. 2010. “Alligator snapping turtle”. Illustrated Encyclopedia of Animals of the World. Metro Books, New York.
Photo credit, me. Animal credit, Rob Carmichael and the Wildlife Discovery Center.
Those “shameless little libertines” (periwinkles) are the tiiiny little snails you see covering rocks on rocky beaches. Shameless or not, they are adorable; scooting along the rock face and scraping algae off with their radula (a kind of tooth) like little gooey shelled cows. OK, yeah, they’re nothing like cows. But even their genus name is cute. Littorina. Of course, there are plenty of cute animals in the world, certainly cuter than one snail, so what is so special about Littorina? LUNGS. That’s right, amongst their rocky intertidal adaptations, besides a strong grip, shell and densely packed groups to resist water loss and wave shock, Littorina have LUNGS. Barring hypertonicity and dehydration, Littorina actually prefer life above water.
And now for something else seemingly completely different.
But I’ll explain soon.
Pop quiz! What is “polyandry”?
Is it:
A. A species of chiton
B. The little floaters on your eyes
C. A social system in which a female will acquire a male harem or mate with multiple males
D. Shut up, it’s summertime now quiz time!
E. Drag queen name
To everyone who answered C, you are correct! To everyone who answered D, cut the sass mouth, I will make you learn and assess your knowledge retention if I please.
Previously when I discussed polyandry, I pointed out the logistical problems of female promiscuity and caring/bearing offspring. However, sea horses proved an excellent example. Since the males carry the sea foals to term, the costs of polyandry on baby birthin’ are low. Dolphins, though followers of the fission-fusion social system, found another way that polyandry works. Female dolphins may not bear multiple calves by multiple males, but promiscuity ensures that the local males leave her alone as any of them could be the baby daddy. Trust me, this is a solid plan. If you had to deal with gangs of aggressive/randy/aggressively randy male dolphins on a daily basis, you’d get it.
Why am I rehashing polyandry? Because Littorina.
Monty Python didn’t know it at the time, but they were right about how fast and loose the Littorina play it. For each 70 baby brood, there is an average of 19 fathers responsible. The bigger the brood (or clutch), the more baby daddies. It’s pretty incredible that the lady Littorina can fertilize one clutch with more than one mate’s sperm, but WOW. Showing off maybe? Maybe. I’ve heard of increasing genetic diversity with multiple mates, but this is overkill. Over-fertile? Anyway, that’s a lot of mates. You would think that much business going down would get in the way. Or at least knock a gal off her rock. But the running theory is that dissuading all those ardent suitors would be more work and less reward then just going on with life. Scrape some algae, scoot about, mani-pedi with the girls…just ignore the impassioned fellow tagging along. Can you imagine? “I don’t know about this guy but…ehhh, asking him to leave sounds like WORK. Better not.”
Lazy little libertines.
Source
Marshall, Michael. March 24, 2010. “The world’s most promiscuous…snail.” Zoologger. New Scientist. June 19, 2013.
Yancey, Paul. “Rocky Shore- Abiotic Factors and Adaptations.” Marine Biology. Whitman College. Walla Walla, WA. 5 4 2011. Lecture.
Inspiration credit Paul Yancey.
NOTE: I do not, nor do I believe Monty Python does, approve of the gay-bashing featured in the video. Whelks should live however they please without fear of abuse. Seriously though, Monty Python enjoyed lampooning such behavior to point out its ridiculousness, but this was a bit much. Anyway, this is me awkwardly explaining the video was funny and relevant to recent scientific discoveries, and no offense was intended.
Following the Deepwater Horizon rig explosion and subsequent spill into the Gulf of Mexico there was a lot of talk about clean up efforts, including talk of oil-degrading bacteria. Seems mighty helpful of the bacteria, degrading all this crap we spilled, but the fact is that the bacteria are entirely selfish. I’ve thought that saying the bacteria are “degrading” the oil sounds more like they’re kindly disassembling molecules for us. The fact is that oils are hydrocarbons and there are many kinds of bacteria that need it as a carbon and energy source. These bacteria possess specialized enzymes for digesting the oil into carbon dioxide and water. However, oil is made up of a variety of chemicals so no one species of bacteria can digest all of it. Different species chow down on different hydrocarbons using different enzymes. But! Species without the gene for producing such enzymes can receive the gene for these enzymes either via human-mediated bioengineering, or the natural process of horizontal gene transfer. Bacteria can actually give good genes to other bacteria. It requires a sex pilus to connect two cells and through which the donor can send a copy of their genes for oil-degrading enzymes.
Unfortunately, oil digestion is not a quick process. The speed depends on environmental conditions such as temperature, pH and availability of other nutrients, as well as the actual size and composition of the oil spill in question. Regardless, the presence of bacteria make a big difference in controlling and shortening long term effects of hydrocarbon contamination in the environment. By the way, I’ve been talking a lot about oil spills, but microbes are widely used for a variety of chemical spills involving hydrocarbons.
Source
American Academy of Microbiology. 2011. “Microbes and Oil Spills-FAQ”. Fisheries and Oceans Canada. June 16, 2013. < http://www.dfo-mpo.gc.ca/science/publications/microbes/index-eng.html>
Photo credit LBNL (Lawrence Berkeley National Laboratory)
While researching my post for tonight, I’ve found sources contradicting what I found last night regarding oil-degrading bacteria. Namely that those are typically aerobic, rather than anaerobic, bacteria.
That is all.
What started as a request from my father for a Father’s Day blog topic ended in my education being denounced as incomplete because I don’t read Superman. Also I think my dad wants to be silicon-based. Maybe. That part was slightly unclear. Anyway, I think that means his present will be a bit more difficult to accomplish this year. I guess that’s what I get for waiting until the last minute. But! The Dado did express a desire to learn about microbes that do not rely on oxygen to survive, and what The Dado wants, The Dado gets (whether we like it or not…like the soul patch).
The reason for the different oxygen requirements of different microbes lies in cellular respiration. Respiration is essential for gleaning ATP (adenosine triphosphate, a high energy molecule that acts as “energy currency” in cells) from organic (or inorganic, depending on the microbe) compounds. Microbes have a variety of respiratory pathways, but I won’t bore you with all those right now (I can always bore you with them later). All the different pathways require a terminal electron receptor. That is, a molecule or atom that accepts electrons from the molecule being oxidized during respiration. Microbes that utilize oxygen as the terminal electron acceptor are called aerobes and those that use other compounds are called anaerobes. These groups can then be further broken down based on oxygen tolerance.
Aerobes that absolutely NEED oxygen are called obligate aerobes and contrast from facultative aerobes that may grow anaerobically, depending on conditions. E. coli is one such bacteria. Microaerophiles, as the name suggests, love only a little air. Much more than 5-10% oxygen concentration (atmospheric oxygen concentration is 20%) and they can’t grow. Likely they have oxygen sensitive proteins, so despite the fact they need oxygen for respiration, too much of the stuff will kill them. More oxygen tolerant bacteria produce more enzymes (such as catalase and superoxide dismutase) that work together to break down toxic oxygen compounds into safer compounds.
Obligate anaerobes are the opposite of obligate aerobes; they are completely oxygen-intolerant. These stroct anaerobes ferment or respirate anaerobically using compounds such as sulfates and nitrates as their terminal electron acceptors. However, their sensitivity to oxygen is not necessarily due to a lack of the detoxifying enzymes mentioned previously and could be cause by other factors. Aerotolerant anaerobes, on the other hand, don’t give a crap about oxygen and will grow with or without its presence. Typically they use fermentation as their respiratory pathway with pyruvate as the terminal electron receptor.
Aerobes have gotten a bit of press lately for their applications in degrading hydrocarbons associated with chemical spills. But more on that later; got to go figure out how to surprise The Dado with a silicon-based biology. I have a feeling a blindfold won’t cut it.
Enjoy the view, Dad. You’re going to be a metalloid soon.
Source
Brown, Alfred E. 2009. Benson’s Microbiological Applications: Laboratory Manual in General Microbiology. McGraw Hill, New York.
Photo credit, me.
I LIVE! My statistics class is finished and I can write weird shit on the internet once more. Huzzah!
So let’s get right down to business. Not just any business, business, if you know what I mean. Right? RIGHT? Ya know…IT? The deed…? Sex. I’m going to talk about sex. Jeez, you guys are hard to fake talk to, may as well just talk to myself! Anyway, before the tittering (heh, “tittering”) begins, know that I will be talking about sexy times AND asexy times. That is, I’m comparing sexual and asexual reproduction. Bow chicka wow wow!
Now, although we’re waiting on input from single-celled organisms, plants* and…well, most animals, the consensus is that sex is pretty great. So that’s not a real consensus, sue me. But if you throw two sexually reproducing organisms in a room (maybe not actually throw them) and give them some alone time, they’ll make little sexually reproducing organisms and soon you’ll hear the pitter-patter of little genetically variable, possessive of good genes from both parents, feet. Independent assortment (Remember Mendel?) and random fertilization (the match up of different gametes with different chromosome combinations) makes for some incredible genetic variation potential. There are 8.4 million different chromosome combinations one gamete (sperm or egg) can possess, so that’s 70 trillion possible sperm/egg pairs, each with a unique combination of chromosomes. All the stuff about everyone being a miracle is true; each one of you was a one in 70 trillion chance. Unless you’re identical twins. Then you aren’t a miracle. You are a poseur.
All this variation means sexually reproducing organisms are (as a whole, not individually) completely prepared for environmental variability. They can evolve their way out of all kinds of shit. So sex is awesome! It results in genetic variability, the combination of good genes from each parent and word on “the street” is that it’s enjoyable, too. What’s not to like? EVERYTHING.
OK, maybe not everything, but the variation that makes sexual reproduction so good, can also be a big problem. Besides both parents contributing good genes, bad genes can also get thrown in and good gene combinations may be lost completely. In addition, it takes a lot of energy to find a mate and then reproduction is pretty slow. So what happens if you cut out the sex? Asexual organisms can reproduce by budding, division (only single celled organisms, but it’s funny to imagine koalas dividing) and parthenogenesis (two eggs mix in self-fertilization). Unlike sexual reproduction, the parent can pass on 100% of their genes and not worry about trying to get a date or bad genes from some lame baby daddy wrecking everything. Reproduction is also a lot faster. HOWEVER, without the genetic variability, asexual organisms can’t really handle variable environments, are susceptible to disease and can’t “lose” bad genes or gain better genes.
I say it’s a toss up. But HBO would be out of a job if we all went asexual, so may as well support the economy
Source
Bohn, K.M. 2011. “Sexual Selection”. Ecology. Whitman College. Walla Walla, WA.
*Yes plants have sex. Flowers are just colorful plant genitalia and “pollination” is just science slang for plant sex. Think about THAT next time you buy a bouquet for your sweetie.
Such lovely…flowers.
So sorry for the prolonged bouts of silence, guys. I’m just finishing up an online stats class and I’ve had a quiz, a final project and a final to work on/prepare for. The madness will end soon, but until then my posts will be a little sparse. Now onto more fun things.
Coral is fun, right? Right. They are colonial polyps of the phylum Cnidaria, and what’s more fun than saying “polyp”? NOTHING. Possibly cake. But anyway! As cnidarians, coral are related to jellyfish and anemones, and like anemones, they possess nematocysts (stinging cells) on their tentacles for filter feeding. Unlike anemones, they maintain a symbiotic relationship with algae, they help out with stuff like cooking, cleaning, provide energy through photosynthesis, etc. You know, symbiont stuff. However environmental stressors (like ocean acidification) can cause the coral to eject the algae, a process called bleaching (for the color change that accompanies the algae eviction) from which the coral do not usually recover. Barring changes in/removal of temporary stressors. For those of you crazy chemistry people, my marine bio professor has been researching the protective, anti-bleaching role of organic osmolytes (imagine a chemical cushion against change) in coral. You can check some of it out here and here.
Although coral colonies have a wide variety of shapes, species follow one of three strategies: columnar, planar and massive. Columnar coral grow tall, fast, in order to stay in the sun and avoid getting shaded out. Planar coral would be the ones doing the shading; they don’t grow tall, but they grow wide and flat (like the one in my picture) to prevent other coral from growing around them. The wide plates of these coral are also great for absorbing sunlight. Finally, there are the massive coral. These grow slowly, it may take hundreds of years for one to actually qualify as “massive” and in the meantime, they have competitors ready and willing (or at least as willing as a coral can be) to destroy them. However, massive coral have a secret weapon, massive coral have war tentacles. Excuse me, WAR TENTACLES. WAR TENTACLES are TENTACLES used in WAR. Territorial coral of any species just stretch out their stingy tentacles and go at it, massive coral are just better at it and have evolved to possess TENTACLES particularly suited to WAR. It’s a slow war, but give them a break. They’re coral.
Sources
Yancey, Paul. “Coral Reefs.” Marine Biology. Whitman College. Walla Walla, WA. 5 4 2011. Lecture.
Picture credit: me.
Daily Science (blog) 