Score
Title
552
AskScience Panel of Scientists XVII
440
AskScience AMA Series: I am a squid biologist, AMA!
6909
What exactly is happening to your (nerves?) when circulation gets cut off and you start to tingle?
5831
At what point is a particle too small to cast a shadow?
21
Has Alzheimer's ever been observed in animals?
12
What exactly do they do with your body when you die, if you're an organ donor?
4
Do plants require constant nutrition or do they eat in cycles?
20
How does quantum mechanics explain covalent bonds?
5
If 1+2+3+... can be "regularised" to -1/12, does it follow that 1+4+9+... can be 0 or that 1+8+27+... can be 1/120?
178
How do most wild animals die?
4
How come water does not flow deep into our ear canal?
6
What percentage of the light that hits your retina is actually absorbed by it?
7
Why are long things flexible while short pieces of the same object are rigid?
3
How do zookeepers avoid accidentally domesticating animals in zoos?
90
What do scientists mean when they say "We only know what makes up 5% of the Universe"? What makes up the other 95% of the Universe and how come we don't know what it is ?
3
How do radiators know when the room has achieved the set temperature?
6
How do we know that climate change is caused by humans?
4063
How do our bodies build a tolerance to alcohol?
3
Is there any sort of concept of a genomic efficiency, i.e., is there any benefit to having a higher ratio of coding DNA to junk DNA?
3
If electrons behave so sporadically, how can scanning electron microscopes have such clarity of resolution?
1
How does letting a dish soak with soap and water work?
7
How does Lake Victoria replenish itself as the source of the entire Nile river which flows out and empties into the Mediterranean?
2
Would a wire or antenna, where a signal with 550THz is sent through, radiate light?
11
How exactly does White Blood Cell detect bacteria ?
0
If a person somehow was able to get to the surface of a gas planet, let’s say Jupiter, would they be able to walk on the surface or would they fall through?
67
Is there a way to measure sharpness - like a scale of sharpness? Thank you
0
Why does Marathon running cause toxin buildup in the Kidneys?
0
If a man has a stroke, does it have any effect on the quality of his sperm?
18
What prevents people in the United States from contacting Malaria from mosquito bites?
320
Does the temperature of air effect the distance sound can travel?
0
Can you "catch" helium?
0
Do oil pipe lines have a problem with the pipes expanding do to heat?
3
What happens inside a cats’ body when it ‘fluffs up’ as a result of being threatened? Also, is it an automatic response?
14
When I drop an insect (I.e an ant) from a large height (relative - from my chest to the ground), does it “hurt” as bad as it would for us?
6
If electrons move in a copper wire not by each electron travelling all the way, but by bumping into the one ahead and pushing it forward, how can electricity travel faster than the speed of sound of copper?
9
Why does tungsten (and the elements around it) have a high melting point?
6453
Why is the Liver one of the only organs that grows back when most of it is removed?
3
Why does diabetes causes kidney damage?
276
Since the W and Z bosons that mediate the weak force are not massless, does that mean that the weak force does not propagate at light speed?
8
What is the Furry hypothesis, in relation to quantum superposition, and why is it incorrect?
17
How is a breathalyzer a useful metric when testing blood alcohol content?
0
Why are planets rotational axis usually (approximately) orthogonal to their sun (since Planets like Uranus are seen as "wierd")?
17 lythronax-argestes Yes, there are theoretical upper limits on the maximum size which can be attained by any given animal group. (The below is from sauropod biomechanics researcher Heinrich Mallison at [[1]](http://www.askabiologist.org.uk/answers/viewtopic.php?pid=15164#p15164).) At a superficial level, a big animal requires a lot of sustenance for both metabolism and locomotion. In particular, metabolism gets a lot less efficient for large animals as the surface area becomes very small relative to the volume (per the square-cube law). Overheating or starvation would be problems for large animals, which would be exacerbated if the climate of the time is unfavourable (i.e. heat waves, or droughts leading to a lack of food). Then, once you get down to an animal's skeletal structure (talking about vertebrates here), the square-cube law strikes again. Of course, as an animal's volume grows, its weight grows accordingly. However, the tensile strength of muscles and bones do not scale cubically; they scale quadratically. So it becomes harder for an animal's skeletal structure to support it as it grows. Sauropod dinosaurs were really pushing it in terms of the size limit, and they "cheated" in many ways, so to speak. They have columnar limbs, which improves support, and they have bones lightened by air sacs, which reduces weight. Air sacs also alleviated the thermoregulatory problem. And of course their long necks are specializations for efficiently acquiring food.
2 the-real-apelord The base reasons from a structural POV are that: -Mass and therefore weight scales cubically so if something is made 2x bigger in size it becomes 8x heavier -But the cross-sectional area of the load bearing elements (legs for example) only increases with the square of scale so 2x bigger gives you just 4x the area to support 8x the weight so, in this example, the stress (force/area) has doubled. -All materials and structures have a limit to the amount of force/area they can sustain and at some point with increasing size will eventually fail (pancake in pure compression). In short weight grows faster than the area over which the weight has to be spread as a creature increases in size. Another limit is of course the presence of gravity, since weight only exists in a gravitational field. However it's worth noting that even in zero gravity there's limits on the size of a living thing, if that thing hopes to move, since as before mass increases cubically meaning forces required (for same acceleration) increase cubically but again those forces are spread over areas that is only growing with square of scale. There's a cool book called: "Why things don't fall down" that covers this question and lots else.
1 annomandaris Its mostly the square-cubed law, as anything gets bigger, its volume gets bigger a lot faster than its cross-sectional area. so if you take an animals leg, and double length/height/thickness of it, its cross-section will square, but its volume will be cubed. So basically theres a point where that animal thats getting bigger, the bone cant take the weight, and would just split apart. Also the bigger an animal gets, the bigger the problem of overheating gets, getting oxygen to areas of the body, and just how much it has to eat. Brontosaurus's were about as big as an animal can be, and if you notice they have short stubby legs that are really thick and short. and most of their size was a skinny neck and tail.
0 lbruss95 some animals were able to attain massive size due to oxygen availability at the time, with that many resources it was a viable evolutionary strategy to be huge as to avoid predation. If an environment were created with "unlimited" resources, large predators would increase in size to out compete each other. mountain sized animals didn't exist because that would have no evolutionary benefit within an individual's lifetime.
16 0 lythronax-argestes Yes, there are theoretical upper limits on the maximum size which can be attained by any given animal group. (The below is from sauropod biomechanics researcher Heinrich Mallison at [[1]](http://www.askabiologist.org.uk/answers/viewtopic.php?pid=15164#p15164).) At a superficial level, a big animal requires a lot of sustenance for both metabolism and locomotion. In particular, metabolism gets a lot less efficient for large animals as the surface area becomes very small relative to the volume (per the square-cube law). Overheating or starvation would be problems for large animals, which would be exacerbated if the climate of the time is unfavourable (i.e. heat waves, or droughts leading to a lack of food). Then, once you get down to an animal's skeletal structure (talking about vertebrates here), the square-cube law strikes again. Of course, as an animal's volume grows, its weight grows accordingly. However, the tensile strength of muscles and bones do not scale cubically; they scale quadratically. So it becomes harder for an animal's skeletal structure to support it as it grows. Sauropod dinosaurs were really pushing it in terms of the size limit, and they "cheated" in many ways, so to speak. They have columnar limbs, which improves support, and they have bones lightened by air sacs, which reduces weight. Air sacs also alleviated the thermoregulatory problem. And of course their long necks are specializations for efficiently acquiring food.
2 0 the-real-apelord The base reasons from a structural POV are that: -Mass and therefore weight scales cubically so if something is made 2x bigger in size it becomes 8x heavier -But the cross-sectional area of the load bearing elements (legs for example) only increases with the square of scale so 2x bigger gives you just 4x the area to support 8x the weight so, in this example, the stress (force/area) has doubled. -All materials and structures have a limit to the amount of force/area they can sustain and at some point with increasing size will eventually fail (pancake in pure compression). In short weight grows faster than the area over which the weight has to be spread as a creature increases in size. Another limit is of course the presence of gravity, since weight only exists in a gravitational field. However it's worth noting that even in zero gravity there's limits on the size of a living thing, if that thing hopes to move, since as before mass increases cubically meaning forces required (for same acceleration) increase cubically but again those forces are spread over areas that is only growing with square of scale. There's a cool book called: "Why things don't fall down" that covers this question and lots else.
1 0 annomandaris Its mostly the square-cubed law, as anything gets bigger, its volume gets bigger a lot faster than its cross-sectional area. so if you take an animals leg, and double length/height/thickness of it, its cross-section will square, but its volume will be cubed. So basically theres a point where that animal thats getting bigger, the bone cant take the weight, and would just split apart. Also the bigger an animal gets, the bigger the problem of overheating gets, getting oxygen to areas of the body, and just how much it has to eat. Brontosaurus's were about as big as an animal can be, and if you notice they have short stubby legs that are really thick and short. and most of their size was a skinny neck and tail.
-1 0 lbruss95 some animals were able to attain massive size due to oxygen availability at the time, with that many resources it was a viable evolutionary strategy to be huge as to avoid predation. If an environment were created with "unlimited" resources, large predators would increase in size to out compete each other. mountain sized animals didn't exist because that would have no evolutionary benefit within an individual's lifetime.