Is it true that frogs are the closed animals to humans regarding organs, anatomy, etc? What's the link???

Question

CLOSEST, I meant.

What is the link between frogs and humans? Why do we dissect them in high school?

Answer 1

The thing you have to keep in mind is that there is a balance in these things. The closest thing to a human is another human. But you can't dissect or do experiments on those!

Probably the next closest thing would be a chimpanzee. But those are fairly large, mature slowly, and so on. They're not a good pick if you have a limited budget or want to see a significant portion of the life cycle for example.

So most organisms that are dissected of have experiments performed on them are compromises. Mice are one of the most common critters used, both because they are physiologically similar to humans in many ways and because they are small, easy to care for, and short-lived. In 2001, mice comprised more than 60% of all (non-invertebrate) animals used in the UK for experiments (link 1). Insterestingly enough, sequencing of the mouse genome reveals that for just about every human gene there's a mouse equivalent - they share 99% of their genes with us! (link 2)

Frogs are much less similar to humans than mice, but they have other advantages which make them a good choice for some experiments. They don't get infections easily (they secrete a natural antibiotic... drug companies are working on replicating it), like most comparatively 'primitive' organisms they are somewhat hard to kill and slow to break down (I remember using wires to directly stimulate a frog leg muscle that had been severed for more than a day... they would have never worked on a mammal), and perhaps best of all they may be even less expensive than mice. Unlike rats they don't have thick skin, and they have most of the same organs and systems.

So they work fairly good for dissections and experiments where it's not vastly important that they're identical to humans. Compromise.

Answer 2

Frogs are not the closest animals to humans. Other mammals are much closer, of course.

Frogs do have some similar structures, though, and many parts are in the same relative places as those parts in humans.
For instance, you open the ventral side of the frog and you see the lobes of the liver. That's similar to the position of the liver in humans.

A big difference between the inside of these two species is that the frogs do not have a diaphram separating the inside into a chest cavity and an abdominal cavity.