Afarensis is a 3.5-2.8 million year old hominin from the Kada Hadar member of the Hadar formation in the Middle Awash, Ethiopia. He is approximately 41 inches tall, weighs approximately 60 pounds and has a cranial capacity of a whopping 410 cc (approximately). Afarensis is currently considered to be transitional between apes and humans and displays some traits of both. Since he spends a lot of time on the couch watching monster movies, some observers question whether he is an obligate biped (although no one has observed him climbing a tree). He also has a blog called 
I have a case of writers' block at the moment, so you all have to suffer through one more from the archive...It concerns the Bombardier Beetle from Duane Gish fame. Although I don't go into detail in the original post I should mention the Gishs' argument isn't that much different from Behes' argument about the bacterial flagellum...
I had originally intended to do this post yesterday in time for the Friday Ark, but got sidetracked. Normally I like to research what I post about for the Friday Ark and this time is no exception. Which is part of the reason why I didn't get it written. My original intention was to post a couple of picts, find a few links to interesting info about the beetle and discuss how it could evolve. One of the great things about trying to provide interesting scientific information about whatever I post for the Friday Ark is that sometimes I stumble across some really fascinating stuff. This time I struck the mother load. I think, to be more than a little snarky, George Bush should have looked to the insect world for weapons of mass destruction! To be an insect is to be immersed into a nightmare world of chemical warfare.
Chrysomeline (Leaf) beetles, for example, have chemical defense glands. Originally, they synthesized the chemicals themselves. During the course of their evolution, however, the became dependent on plant hosts to acquire the chemicals they use for defense (in other words, they incorporate the host plants toxins into their own defense system). One group within the Chrysomelines (the interuptus group)however, has managed to adapt to a wide variety of plant hosts and uses a wide variety of chemical defenses. One of the more interesting things about this is that in order to go from self synthesized to use of host derived chemicals only requires the change of one or two enzymes. To go from the use of host derived metabolites to use of many hosts also requires the change of one or two enzymes.
Fireflies illustrate another, creepy, way insects can acquire chemical defenses. Female fireflies of the genus Photuris imitate females of the genus Photinus. Once they attract a male of the genus Photinus they eat him! Photinus species have a chemical called lucibufagin (similar to a chemical found in the chinese toad) which are extremely noxious to the insects that prey on fireflies (mainly jumping spiders). So female Photuris acquire the chemical by ingesting male Photinus. Then when attacked they engage in what is called reflexive bleeding and the chemical in their blood drives the predator away. They also incorporate the chemical into eggs when they lay them so their offspring is protected.
Peruvian fire sticks (related to the walking sticks) also use chemical defenses. They are rather unique in that a lot of species, when molting, shed their defensive glands. Fire sticks shed the cuticle lining, but do not shed the gland itself. Consequently, they do not have to wait as long after molting to use their chemical defense. The glands are located near their neck. The chemical is sometimes ejected as a spray but more often is oozed out as a froth and spreads down the thorax. The chemical is related to quinoline and other species of walking stick do not have this type of chemical. In that sense Peruvian firesticks are unique.
Opilionid beetles are similar to the Peruvian fire sticks in the way the use their chemical defenses, but not identical. A bubble of enteric fluid is dribbled out their mouth and onto a track which runs by their glands, where quinonoid paste is injected into the enteric fluid. This bubble then moves down a groove on the beetles carapace. The beetles use it back legs to scoop some of this mixture of and tries to smear it on it's attacker.
Which brings us to the Bombardier beetle. Bombardier beetles compose two branches in family Carabidae (brachinoid and paussoid). The Paussoid branch is believed to be older and more primitive (in evolutionary terms). One of these (Metrius contractus) is believed to be close to the ancestral condition for Bombardier beetles. It has two gland openings near the abdominal tip. The glands themselves are cuticle lined and have two chambers (as in all Bombardier beetles). When attacked the froth is emitted and either runs down a track (if attacked in the front)or builds up near the glands (if attacked from the rear). M. contractus is unusual in that the froth develops into a mist, whereas in brachinoid species it is sprayed in any direction. M. contractus is also unique in that the froth is only 50 degrees centigrade rather than one hundred degrees centigrade as in brachinoid species.
Which brings us to the Bombardier species proper. The species pictured below is Stenaptinus insignis.
A single bombardier beetle can discharge upward of 20 times before depleting its glands (6). The discharges are accompa-nied by audible detonations, and they have been shown to be potently deterrent to a number of predators, including ants (6, 12-15). The spray of bombardier beetles is ejected at 100°C (13). This is because the quinones are generated explosively at the moment of ejection by the mixture of two sets of chemicals ordinarily stored separately in the glands. Each gland consists of two confluent compartments. The larger of these (storage chamber or reservoir) contains hydroquinones and hydrogen peroxide while the smaller one (reaction chamber) contains special enzymes (catalases and peroxidases). To activate the spray, the beetle mixes the contents of the two compartments, causing oxygen to be liberated from hydrogen peroxide and the hydroquinones to be oxidized by the freed oxygen. The oxygen also acts as the propellant, causing the mixture to ''pop'' out (16-18). The heat that accompanies the formation of the spray is perceptible (13) and contributes to the defensive effective-ness of the secretion (14, 15). An early explorer, reporting on large bombardier beetles from the neotropics, commented that when these ''play off their artillery'' they are so hot to the touch ''that only few (can) be captured with the naked hand'' (19). Although it was known that bombardier beetles can aim their spray by revolving the abdominal tip (6), the degree of precision with which they target their ejections had escaped notice.(from THOMAS EISNER AND DANIEL J. ANESHANSLEY, (1999) Spray aiming in the bombardier beetle: Photographic evidence. Proc. Natl. Acad. Sci. USA Vol. 96, pp. 9705-9709, August 1999)
This first picture shows a beetle directing the spray to the front. Note the glob of stuff on it's back. They attached a wire to the beetle by embedding it in wax. They then used the wire to handle the beetle.
This second picture shows a beetle directing the spray backwards.
The third shows the beetle directing the spray to the right rear - note the forceps, they had to pinch it's leg to set it off.
In addition to the insects mentioned above, a wide variety of other insect use some form of chemical defense including: millipedes, cockroaches, ants, termites earwigs and grasshoppers to name a few (but I'm still in shock about the male-eating fireflies. I am used to that kind of thing in, say, black widow spiders, but not in lightening bugs!).
So, we have a wide variety of different chemicals, a large number of different ways of getting the chemicals and delivering them (we could have given details on Opilionid beetles and millipedes as well). In some cases, the differences are caused by differences in a few enzymes. I have done quite a bit of reading on the origins and evolution of these systems, but from what I have read so far Bombardier beetles don't represent that much of a challenge to evolutionary theory. Rather, they seem to be a specialization of several traits already present in nature in one form or another - benzoquinones, for example, are used by a wide variety of insects.
I will probably write some more about this in the future. I just need to do some more research into a really fascinating area of biology (it's referred to as chemical ecology in the literature I've read).
Update 4/8/2008: You might also read this post by Ryan Gregory at Genomicron Reducibly complex bombardier beetles. which totally debunks the creationist/intelligent design mumbo jumbo.
Comments
this bug is awsome I want to learn more stuff about it.
Posted by: Je;Terrel | March 12, 2006 8:03 AM
Yeah, they are pretty amazing...
Posted by: afarensis | March 12, 2006 7:38 PM
seems pretty amazing to be an evolutional by chance thingy.
More like an amazing peace of dezigne
Posted by: andy | November 26, 2006 4:19 AM
Nope, as mentioned in the discussion of leaf beetles, it only takes a few mutations...
Posted by: afarensis, FCD | November 26, 2006 11:04 AM
Mutations....a few mutations and we have an incredible beetle that shoots fire out its back side.
Are not most mutations defects of their original roots.
I find it too hard to believe in chance with any thing that lives. You speak like you are the holder of fact when you can only truely speculate or theorise. Why is the science world so evolutionised in their thinking and can't accept super natural "perfect" design...even if they believed living things were made by other than God, it would be more believable. But by chance and mud puddles....
Posted by: andy | November 26, 2006 6:37 PM
A slight correction, they do not shoot fire they shoot a hot chemical. The heat comes from a chemical reaction. Mutations are not "defects in their original roots" whatever that means. Many are quite beneficial - for example Douc Languars have several mutations in their pancreatic RNASE that allow for the more efficient digestion of cellulose. As for why science is so evolution based, it is because of the overwhelming evidence for evolution.
Posted by: afarensis, FCD | November 27, 2006 1:11 PM
Overwhelming evidence for evolution?
You guys must be kidding
There is no evidence whatsoever for the evolution's very foundation - Macroevolution or the origin of life.
There is no evidence of making life in lab from non living material, and we're talking that it came alive by ITSELF! "We'll give it more time and it'll happen"
Uh-oh.. is that so? If inteligence in lab cannot do it then how in the world it got alive byitself?
And how can a dog produce a non dog? There are different kinds of dogs but they all DOGS!
-Incredible Creatures That Defy Evolution- DVD
http://www.explorationfilms.com
http://www.explorationfilms.com/exploration-films-incredible-creatures-1.html
Did you read book called -I Don't Have Enough Faith to be an Atheist-?
Did you know that it takes more faith to be an atheist (or darwinist) that it takes to be a christian?
Here are few quotes...
"Men stumble over the truth from time to time, but most pick themselves up and hurry off as if nothing happened." - Winston Churchill
"People almost invariably arrive at their beliefs not on the basis of proof but on the basis of what they find attractive." - Blaise Pascal
"Science without religion is lame; religion without cience is blind." - Albert Einstein
"Only a rookie who knows nothing about science would say science takes away from faith. If you really study science, it will bring you
closer to God." - James Tour, Nanoscientist
"God never performed a miracle to convince an atheist, because His ordinary works provide sufficient evidence." - Ariel Roth
"In a grammar school they taught me that a frog turning into a prince was a fairy tale. In the university they taught me that a frog turning
into a prince was a fact." - Ron Carlson
"We hold these Truths to be self-evident, that all Men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the Pursuit of Happiness." - The Declaration of Independence
"If we admit God, must we admit Miracle? Indeed, indeed, you have no security against it. That is the bargain." - C. S. Lewis
"For the scientist who has lived by his faith in the power of reason, the story ends like a bad dream. He has scaled the mountains of ignorance;
he is about to conquer the highest peak; as he pulls himself over the final rock, he is greeted by a band of theologians who have been sitting there for centuries." - Robert Jastrow
"I've noticed all those in favor of abortion are already born." - Ronald Reagan
"Historical evidence moves us a long way towards demonstrating our belief; as a result, the faith that is necessary to fill in the remaining gap is reasonable." - Craig Blomberg
"We did not follow cleverly invented stories when we told you about the power and coming of our Lord Jesus Christ, but we were eyewitnesses of His majesty." - Simon Peter
"Why would the apostles lie?...If they lied, what was their motive, what did they get out of it? What they got out of it was misunderstanding, rejection, persecution, torture, and martyrdom. Hardly a list of perks!"
- Peter Kreeft
"Skeptics must provide more than alternative theories to the Resurrection; they must provide first-century evidence for those theories." - Gary Habermas
"There are none who are as deaf as those who do not want to hear." - Barry Leventhal
"My high school science teacher once told me that much of Genesis is false. But my high school science teacher did not prove he was God by raising from the dead, I'm going to believe Jesus instead." - Andy Stanley
"There are only two kinds of people in the end: those who say to God, 'Thy will be done,' and those to whom God says, in the end, 'Thy will be done.'" - C. S. Lewis
Posted by: Sashko | September 8, 2007 11:13 PM
Sashko - And yet, for all your whining, it only takes a few mutations to get from Metrius contractus to the bombardier beetle and whales still evolved from the artiodactyls
Since you like quotes, here is one that is particularly appropriate:
Posted by: afarensis, FCD | September 9, 2007 10:52 AM
Sashko, Andy,
Why is it you can believe in an all powerful zombie (aka jesus)and his magical escapades but not in evolution?
also, why is it that all scientists are involved in a massive comspiracy to discredit the all powerful zombie? Have you considered that when it comes to experts, they overwhelmingly agree with evolutionary theory? True, majority doesn't make fact, just as when the church ruled, but obviously if evolution can answer some basic questions that religion can't (i.e. why is our blood more similar to chimps then dogs) - maybe it is the better theory, (if you could even call you ideology "theory")
Posted by: Jim | December 6, 2007 10:40 PM
It's easy to see why people get so upset about this issue. A lot of people use hyperbole to make their point and that is a sure fire way to alienate each other.
Statements like, "...how can a dog produce a non dog? There are different kinds of dogs but they all DOGS!" and, "Why is it you can believe in an all powerful zombie (aka jesus)and his magical escapades but not in evolution?" show a total lack of understanding of both sides of the argument--not to mention a lack of respect.
Christians believe in a God who literally created all the matter and energy in the universe and who arranged it so precisely that life and intelligence were came into being. We believe that this God, who is everywhere and in which everything in the universe exists, loved man kind enough that he humiliated himself and lived life as a human to bridge the gap between himself and us. It is a beautiful story of power and love that literally changed the world forever.
Evolutionists believe that over time species randomly change and these changes help them to flourish in an environment that changes. Eventually the random changes cause enough change that so the latest version is non-compatible with earlier versions. (A new species.) It is a solid example of enlightened in our species to recognize, understand and study this phenomenon.
I believe that a life form that does not evolve to adapt to a changing world would be flawed. A mechanism like evolution is to be expected by a designer such as God.
So for all you Christians out there who look at evolution with distrustful eyes, relax. Evolution doesn't describe where life comes from but where the *diversity* of life comes from.
For all you evolutionists out there who know that evolution exists and are pissed that Christians are bull-headed about it, relax. Just make sure that we understand that the existence of evolution doesn't preclude the existence of God.
And for those of you who see evidence of evolution every day but aren't quite sure how it all started/and or aren't quite sure where it all ends, please consider God as an option.
Posted by: Daniel Richardson | December 19, 2007 5:58 PM
afarensis - So even if it only takes a few mutations to get from Metrius to Contractus to the bombardier beetle. It would only take one mutation in which the beetle's two chemicals when mixed would not create the proper defense needed. If the beetle at that stage could not defend it self it would not exist to day. So out of the millions of chemicals available how did evolution find the right two on the first try?
Posted by: John Kelbel | March 17, 2008 5:19 PM
John - I fear my previous statement may have mislead you somewhat. Allow me to clarify. When I said it took a few mutations to get from Metrius to the bombardier beetle I was referring to the chemical defense systems. The defense system of the Bombardier beetle is an extension of the system found in Metrius. Who said it was the first try?
Posted by: afarensis, FCD | March 17, 2008 7:09 PM
For those of you that mentioned all it takes is a few mutations and this beetle would have happened, you are greatly mislead. Did you actually study the science of mutation? Mutations are almost always harmful or neutral, and those that are beneficial cannot create genuinely new genetic information! That is science...not the wishful thinking you propose. Mutations are always random...they are not guided processes. About one time in every ten million times a cell divides, a copying error occurs, which is known as a mutation. The genetic code is never added to. All mutations have a mutagenic power. For example, the mutagenic power of the sun causes skin cancer. It doesn't cause skin cells to mutate and become resistant to skin cancer. This would be equivalent to a telegram giving rise to an encyclopedia! Scientists have yet to find a single mutation that increases genetic information, yet you propose the highly complex chemical reactions happened by a few mutations! The slightest alteration in the chemical balance would result immediately in a race of exploded beetles. Your argument is about as absurd as saying if gunpowder, a fuse, a barrel, and a cannonball "happened to be around" eventually they would put themselves together, carefully load the ingredients in the right sizes and proportions, and then go off in the right direction without blowing themselves up along the way! No, all the components had to be carefully and intelligently assembled, all at once, not in piecemeal, in order to function!
Mutations do not try to supply what an organism needs...for example exposure to harmful chemicals may increase the mutation rate, but will NOT cause more mutations that make the organism resistant to those chemicals. In this respect, mutations are random, whether a particular mutation happens or not is unrelated to how useful that mutation would be.
Posted by: Rob Demeuse | April 8, 2008 3:17 PM
Actually, before making such claims about mutations you should attempt to gain some knowledge about them. The claim that it only takes a few mutations to go from one type chemical use to another is supported by the literature on the subject. Particularly important in this regard are some of the analyses by Thomas Eisner - which demonstrates my contention. You might also look into the work of Zhang on pancreatic Rnases among colobines. It's quite interesting as a few mutations created an entirely new function for the Rnases - one which improved the colobine ability to digest leaves.
Since you mention information, can you tell define "genetic information" for me, make sure it's an empirically verifiable definition. Better yet, can you calculate the gain or loss of information in the above example of colobine pancreatic Rnases? This link will give you all the info you need to make your calculation.
Posted by: afarensis, FCD | April 8, 2008 6:39 PM
Actually most mutations are "nearly neutral" due to a lot redundancy inherent in genetic code. A lot of new information can be added through gene and even whole genome duplications. This redundancy frees evolutionary constraint, leading to the potential for novel mutations. A great example of this are the Hox genes that control body plans (and they just so happen to be distributed quite nicely across major groups). Everyone should go look them up, but to the typical evilution dissenter that would require a degree of biological literacy unheard of amongst your species.
Posted by: the teacher | April 14, 2008 12:08 AM