The Biology, Agriculture, and Paleontology thread

I'm guessing it's from the Dutch-Low German "dichtheid/ digtheid" butchered together with "Greek".

It's basically calling that shape of queen extra dense. Yay: zoology goes all GlaDOS with the weight jokes.

One, the suffix -iform is Latin, not Greek.

Two, what little I managed to find are claims that it derives from the supposedly Greek word dichthadios, with the supposed meaning of "double". Of course, I could not find anything to support this claim, especially since the actual word for "double" in Greek is diplos (διπλός).

Fiat iustitia, et pereat mundus.

There was a reason I put "Greek" in inverted commas. Dog Latin, often misidentified as Greek.

I guess to find out which route to the name is most likely, you need to track down who coined the phrase. But, I bet Dutch or Swiss.

The funny thing is that there is another name for the same thing that is shorter and has a verifiable etymology: physogastrism (from two Greek words that literally mean "bladder-stomach" when combined in that order, respectively).

edited 23rd Aug '16 1:54:16 PM by MarqFJA

Fiat iustitia, et pereat mundus.

Been reading about compound eyes on Wikipedia and elsewhere. It says that due to the physics involved, compound eyes have an inherent limitation on how good the resolution of the images they get can achieve (maximum of 1°... whatever the "°" symbol means), unless the many lenses in such eyes actually operate as "phased arrays", which is (apparently) very unlikely. What is meant by that last bit? What does it mean for a eye's lens to work as a "phased array", and is it possible for an animal eye, simple or compound, to work that way?

In case the answer requires more physics-related knowledge than biology-related one, I'm crossposting this to the Physics Thread.

edited 7th Sep '16 11:06:39 AM by MarqFJA

Fiat iustitia, et pereat mundus.

To honest, I think compound eyes actually work more effectively than we give them credit for. Even if the eyes give flawed data with many holes to patch, insects have had 65 million years to at least tweak the visual processing to get the maximum from the minimum.

My main concern is that all those Big Creepy-Crawlies that have been depicted with compound eyes and visual acuity that is either implicitly or explicitly just as good if not better than human vision are apparently in direct contradiction with the reality of how compound eyes work.

edited 8th Sep '16 10:02:08 AM by MarqFJA

Fiat iustitia, et pereat mundus.

It's not a contest. And, when you're dealing with such fundamentally different approaches to the same problem (in short: how to acquire and process data from the electromagnetic spectrum without frying yourself), trying to directly compare them is... just stupid. They both get by sufficiently, with some horrible design flaws due to circumstance. <shrugs>

They're just that fundamentally different that neither side is going to fully grasp the intricacies of the other's sensory and perceptual landscape.

I don't get your logic. I understand that compound eyes do work well for the size scale of the arthropods that have them, but from what I gathered it's a verified fact that scaling such an eye design to the size of humans and similarly/greater sized animals does not work when it comes to image resolution, because for the compound eye to match the performance of the human eye in that regard at the human scale, the compound eye needs to have a diameter of over 10 meters.

edited 8th Sep '16 11:14:06 AM by MarqFJA

Fiat iustitia, et pereat mundus.

<shrugs> So I get told. But, the reality may not scale up as expected, given a lot of the unknowns.

And, we have no idea how compound eyes would affect the visual processing side and visa versa when scaling up. Feedback affects every aspect of design. So, the eye placement and shape of the head, proteins used... everything would differ. Not necessarily in predictable ways, either.

It's also rather hard to ask e.g. a mantis shrimp its take on how it perceives the world. And, where it thinks things go weird. Or how it would think scaling up would work.

edited 8th Sep '16 11:47:44 AM by Euodiachloris

OK, so... about the phased array thing. Do you have any idea what's meant by that?

Fiat iustitia, et pereat mundus.

Something, something ham radio from over 20 years ago? Basically, it's triangulation to the max using an array of receivers.

Think Hubble. And, how that ran into trouble with the software-hardware integration. :/

It's a form of detection that uses a mix of constructive and destructive interference to optimally send and receive signals in a certain direction while reducing the signals received from other directions

Modern radar systems use it a lot because in those wavelengths it can be done by just messing with the electrical phase of individual elements. Lets you aim your radar without having to physically move the dish like older styles. In military applications it also means that you can aim it at lot faster.

It can be done in the optical wavelengths as well but I don't know if insects would be able to do it.

So, I happen to have some questions regarding the measurements of lung airways:

• I was told that the lung airways consist of a single layer of cells attached to the basement membrane. Is that the case?
• How thick is the cell layer? Is it the same thickness for all the different branches of bronchioles?
• What is the thickness of the mucus layer in the airway? Is it the same in all the bronchioles?
• The body uses surfactants to stabilise the mucus layer. Any estimates on their concentration?
• What are the corresponding numbers in the case of an Asthmatic person?

edited 9th Sep '16 5:04:40 AM by Elfhunter

If I knew how I know everything I know, I'd only be able to know half as much because my brain would be clogged up with where I know it from

I'd settle for having the first part being explained for now, then.

Fiat iustitia, et pereat mundus.

I'm not entirely certain myself. Most of what I learned about them was for stuff in the microwave and radio range transmission/reception.

Hi, I hope this is the right thread.

Giraffrs, previously thought to be a single species, are divided into four different ones in this study: http://www.cell.com/current-biology/fulltext/S0960-9822(16)30787-4

edited 10th Sep '16 11:33:56 PM by CrownofDawn

The only thing that makes life possible is permanent, intolerable uncertainty: not knowing what comes next. - Ursula K. Le Guin

So, the distinct populations without gene transfer, and with clear physical barriers between them, get a new label. And said label is the only thing that matters...

@Elfhunter:

Yeah, it's true that the walls of the alveoli are only one cell thick. I don't think that's the case for the bronchi and bronchioles though? Not sure.

I'm afraid I don't have any hard numbers. But the amount of mucus will depend on a couple of factors like if the airway is inflamed, how good the system of moving the mucus around is functioning. In normal airways I don't imagine it's very thick.

Be not afraid...

Say, for a bipedal animal, what are the pros and cons for having digitigrade legs rather than plantigrade ones? What about having a "hybrid" of the two, where instead of walking on heavily modified digits, the animal walks on actual feet while what would normally be the tibia and fibula (i.e. lower leg) is split in two, with a backward-facing second knee joining these two portions together?

Fiat iustitia, et pereat mundus.

Plantigrades are better at weight bearing, digitigrades are better at maneuvering and acceleration.

Also, limb bone development is based on ancient stuff and isn't really good at increasing the number of elements, and that development, well, you can shift your weight bearing surface by moving your feet, so, very umprobable.

Remember, muscles are there, tendons are there. The lenght of the very elastic tendons is useful for speed, as tendons extend from the upper tibial area downwards, while thick limbs and not many articulations is good for weight-bearing and force. So nope, wouldn't really do any good.

edited 1st Nov '16 2:12:24 PM by Eriorguez

I was more thinking of a Mad Scientist trying to genetically engineer a Transhuman Ultimate Lifeform.

... I'm not sure I understand the relevance of "shifting your weight bearing surface" here.

Fiat iustitia, et pereat mundus.

The relevance is that if you have your metatarsals vertical to your digits, as a digitigrade posture involves, you have more weight in top of less surface. If you have your metatarsals horizontal, as in plantigrade postures, you have more surface and less weight on top of that, so it is more stable.

If you tiptoe on wet sand, you'll leave deeper footprints. Seriously, it is basic physics, it is the basic concept of pressure (force/area), and Newton's third law applied to self-preservation.

I already understood this principle. It's the way you phrased that part of your previous post that confused me (there is more than one way to interpret "by moving your feet").

What about the knee(s) in both digitigrade legs and that made-up hybrid form I described? Do they have any effect on a biped's movement?

Fiat iustitia, et pereat mundus.

Digitigrade "reverse knees" are ankles and work as ankles. Huge-ass bony process in the back, so the achilles tendon can anchor to it. The achilles tendon pulls the foot backwards and thus causes the movement. Longer feet means a longer stride with the same effort, but that requires going digitigrade or even unguligrade, to get stability.

So no, your solution ignores how a leg works.

Plus, I guess a mote apt way of having 2 varieties of feet posture would be, well, moving the goddamn foot, rather than trying to build an articulation in the middle of a bony rod.