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38 votes

Why do wasps have "wasp waists"? What's been optimized?

Why do humans have such a flexible shoulder? Our ancestors relied on throwing things so the ones who could throw things better did better. What is the wasp's equivalent weapon? The stinger. Wasps ...
Jeremiah's user avatar
  • 839
23 votes
Accepted

How did the largest/longest dinosaurs hold their head and necks up?

There are lots of papers on this. A good summary article is Why sauropods had long necks; and why giraffes have short necks, by Taylor​ and Wedel. They list a number of anatomical features that ...
iayork's user avatar
  • 14.2k
8 votes
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Why does resting potential not become continually more negative?

The resting membrane potential is due to internal/external differences in ion concentrations and very importantly differences in permeability to those ions. The fact that the sodium/potassium pump ...
Bryan Krause's user avatar
  • 45.9k
8 votes

How do disulphide bonds in hair cause curling?

Nice question. I must say it took me many hours to get satisfactory answer. Hairs are made of keratin molecules, which contain cysteine. Cysteine has thiol (-SH) group, by which it can form disulfide (...
another 'Homo sapien''s user avatar
6 votes
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Any simulations of four-winged dinosaur flight? (microraptors)

Note nowhere in the article does it mention the rear wings flapping. The rear wings do not provide lift, they are acting as control surfaces to improve stability and maneuverability. (think of the ...
John's user avatar
  • 14.7k
5 votes

Any simulations of four-winged dinosaur flight? (microraptors)

There is a good attempt at a simulation of 4 winged flight of Microraptor on BBC's Planet Dinosaur. There's another Planet Dinosaur video about their venomous teeth and hunting tactics. And a ...
bandybabboon's user avatar
  • 10.4k
4 votes

Highest bite force of a wolf?

The range from mean to maximum of wolve's bite force is huge. Is it really? According to this Wikipedia page, (Scully, C. (2003). Oxford Handbook of Applied Dental Sciences. p. 151) claims that human ...
Jam's user avatar
  • 1,506
3 votes

How would an animal with legs longer than its torso perform?

Short answer: creatures with such morphology and features (except for hunting humans and climbing very well) already exist, and yes, it's the Giraffes. You see: Giraffes are actually quite fast, they ...
KGM's user avatar
  • 323
3 votes

Why do we have the tibia and fibula (a 2nd bone) in the lower leg?

It does function in the rotation and stabilization of the foot, but that is not why we have it, even species in which it serves no function still have it. A bone does not necessarily have to have a ...
John's user avatar
  • 14.7k
3 votes
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What is the acceleration profile of the greyhound?

I'm going to try to break this up a bit to address your sub-questions. Most of it is summarized from Williams et al 2008--and almost all of the work I'm referencing comes from the Royal Veterinary ...
Kara's user avatar
  • 587
2 votes
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Why metacarpus is considered hand proper?

Proper in this instance means the main body of the hand, the part that has no other identifier. the fingers and wrist have other terms to identify them, the hand proper does not. If I say the the hand ...
John's user avatar
  • 14.7k
2 votes

Any simulations of four-winged dinosaur flight? (microraptors)

Several models have been proposed, challenged, and revised over the past two decades: Origin of Flight: Could ‘four-winged’ dinosaurs fly?, Nature (2005) A previously published reconstruction ...
brazofuerte's user avatar
  • 1,582
2 votes
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What’s the term used to define a terrestrial being that moves by using six limbs?

Hexapedal. From wiki > Hexapedal Having six legs Note that Hexapoda is a taxonomic group including insects and the smaller groups that are Collembola, Protura, and Diplura.
Remi.b's user avatar
  • 68.1k
2 votes
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In human anatomy / biomechanics, what is the motion called when the arm swings sideways so the elbow moves in an arc of 90 degrees?

It’s humeral retroversion at a 90 degrees abduction angle with extended elbow and slightly internally rotated shoulder.
user859786's user avatar
2 votes
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Biomechanics of cells (stress, strain, tension..)

Strain and stress are two essential quantities in elasticity theory, corresponding to the deformation and the forces appearing in response to this deformation. Tension or tensile stress is a ...
Roger V.'s user avatar
  • 3,852
1 vote

In human anatomy / biomechanics, what is the motion called when the arm swings sideways so the elbow moves in an arc of 90 degrees?

Shoulder Horizontal Abduction/Adduction. https://www.youtube.com/watch?v=R3xJDsJ_Nw4&ab_channel=InteractiveBiology "the motion of bringing the arm across the chest is called shoulder or ...
barlop's user avatar
  • 735
1 vote
Accepted

Is there any small animal that can jump over a meter high/long?

no animal smaller than 5 cm can jump higher than 1 meter. grasshoppers and locusts have wings which supposedly disqualifies them. https://www.guinnessworldrecords.com/world-records/highest-jump-by-an-...
Ark Lomas's user avatar
  • 933
1 vote

Highest bite force of a wolf?

In this article (Bite forces and evolutionary adaptation to feeding ecology in Carnivores) they say, that bite forces of wolf (Canis lupus) is 774 N. Literature (Maximum estimated bite force, skull ...
Olga Świder's user avatar
1 vote
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Reference for the bite force for Nile Crocodile

Here is a video by Brady Barr (video in YouTube) measuring 5000 lbf for an adult Nile Crocodile. This is equivalent to 22.24 kN (more than 2.2 tonnes of force). This result is also refered here (Getty ...
Triceratops's user avatar
  • 1,176
1 vote

What is the purpose of the viscous gel in the Pacinian corpuscle?

Short answer The adaptation process in Pacianian corpuscles (PCs) is mediated via the outer capsule. This capsule is an onion-like structure that quickly molds itself to pressure stimuli, thereby ...
AliceD's user avatar
  • 52.5k
1 vote

Are there biological ratchet cycles that are small in number?

First I would in return ask why the actin-myosin coupling should not qualify - the many repetitions of this contractile unit never contract at exactly the same time, and their combined contractile ...
Armatus's user avatar
  • 7,670
1 vote
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How does the brain alter/inhibit muscle reflexes?

how exactly the brain interfaces/controls/disables such automatic muscle reflexes when it needs to? A: At multiple places within a hierarchical system: In a simplified way, the Motor cortex is the ...
Keno's user avatar
  • 220
1 vote

Why do flagella form a bundle only when they rotate counterclockwise during chemotaxis?

In principle this can happen, but you have to read up on flagellar dynamics and polymorphic transitions (Real-Time Imaging of Fluorescent Flagellar Filaments, Turner et al. 2000). From Howard Bergs ...
Marius's user avatar
  • 266

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