The study of the internal structure of organisms
4
votes
2answers
130 views
Did dinosaurs have more than one brain? If so, why?
I once remember reading (15 years ago) that dinosaurs had two brains. One for their head and another one for their digestive functions. What is the current opinion on this theory? Has more evidence ...
1
vote
1answer
25 views
Is stereo olfactory ability restricted to humans?
Most animals I see around seem to have two nostrils - humans, snakes, birds, fish .. and so on. From reading online I see that 2 nostrils provide a stereo olfactory effect. This stereo effect is ...
3
votes
1answer
43 views
What limits the size of fish compared to marine mammals?
The largest extant fish species is the whale shark (Rhincodon typus). With a length of 13 meters and a mass of about 20-30 metric tons, the whale shark is relatively small compared to the largest ...
7
votes
0answers
79 views
Do the majority of fish lack scales on their heads?
Based on pictures, it seems to me that a vast majority of fish species that have scales do NOT have scales on their heads.
Is that fact true?
To make this properly answerable:
lets' define a ...
3
votes
1answer
26 views
What accounts for size variation in breeds of dogs?
My assumption is that dogs vary so much in size because of artificial selection pressures coming from human breeders, but are there genetic loci that roughly determine approximate size? Do other ...
14
votes
2answers
234 views
Why Is Most Life Symmetrical Externally But Not Internally?
Mammals, reptiles, arachnids, insects, etc are all as far as I am aware symmetrical in appearance.
Take a human for instance, make a line from the top of our head right down the middle. However, ...
8
votes
1answer
119 views
Do antigens protrude through the capsule/slime layer in prokaryotic organisms where these features are present?
In prokaryotic organisms that have a slime layer or capsule, do intrinsic/extrinsic proteins and other molecules that could be used as antigens protrude through the capsule?
I assume that they ...
5
votes
1answer
568 views
Do other male mammals except for humans have nipples?
When I grew rabbits, I had a pair, one male and one female. And while the female's nipples were quite prominent, especially after giving birth, I don't remember the male having any nipples at all.
Do ...
10
votes
1answer
182 views
Evolution of long necks in giraffes
In this question, the OP uses giraffe necks as a supportive example of evolution. Is the mechanism described in this post accurate? At some point, I thought I remember hearing that giraffes did not ...
1
vote
0answers
39 views
Text/resource with information on all skeletal muscles and their motor units
Something analogous to an encyclopedia on baseball players with a list of all thier stats would be ideal.
I'm not looking for just generic muscle names, locations and illustrations.
Good answers ...
7
votes
1answer
107 views
Skeletal muscle without antagonist
Is there any skeletal muscle that does not have an antagonist? Excluding circular muscles such as around eye and mouth.
The reason why I am wondering is because in biology normally nothing is ever ...
8
votes
1answer
423 views
Is there a correlation between muscle fibers and body types?
I have been told the number of muscle fibers a particular muscle has varies from person to person. Unfortunately, the person who told me this did not know much more than this. Initial searching on the ...
9
votes
1answer
323 views
Why are there nail growth differences between humans and other mammals?
When a cat is growing, his nails are growing with him to some extent. A grown cat has a fixed nail length that is not extending.
By contrast, human finger nails just keep on growing, so we have to ...
6
votes
1answer
521 views
What is the average Leg-to-Foot Length/Width Ratio?
I'm making a program that estimates a probable size (widest width and longest length) for a human's foot given the length and width of the leg to which it is attached. However, try as I might, I can't ...
12
votes
2answers
282 views
What is the morphological difference between Leydig cell in human and pig?
The pig is only an example, just an animal. Leydig cells have protein inclusions (Reinke crystals) that are mostly made of crystallised lipofuscin. They are secretory inclusions i.e. cells formed in ...
