The Most Primitive Respiratory System

[chikis]

Here is a question that I just came across while reading:

Which of the following has the most primitive respiratory system? A. Rat B. Fish C. Toad D. Grasshopper E. Lizard
I read thoroughly, with a view of having an answer to the question. Uptill now I have not made any success. Folks in the forum, please let's discuss it with a view of arriving at a correct answer.

[JackBean]

I would take it phylogeneticaly. Hardly can some insect have more developed respiratory system then mammal, can it?
This should probably help http://en.wikipedia.org/wiki/Respirator ... physiology

[Darby]

It's a really dumb question - just applying the word "primitive" indicates the questioner doesn't know what they're asking about...

[chikis]

Darwins's theory of evolution is the widely held notation that all life forms is related and has descended from a common ancestor; the birds and the bananas, the fishes and the flowers.
Darwins's general theory presumes the development of life from non-life and stresses a purely naturalistic.
Looking at "embroyology", one of the evidence of evolution.
The embroyos (the earliest stage of and development of both plants and animals) of fish, reptile, birds and mammals are very similar and this are evidence that they evolved from a distant common ancestor. Embroyology shows that all have gill slits and tails in their embroyos like those of a fish.
I can use this theory to pick fish out as the animal that has the most primitive respiratory system. How about that?

[Darby]

If your choice were exclusively vertebrates, that might work...

[chikis]

@Darby
What do the word, "exlusive" meant in your last post in this thread? Explain, let me know how I will and what to reply.

[Darby]

The progression you gave was only applicable to vertebrates; a grasshopper would be out of the sequence entirely for respiratory systems.

[Darby]

Actually, I'd like to add that lungs aren't more advanced than gills, anyway, they're just a structure that works under different conditions. Gills are often much more efficient, since they need to get oxygen from a much lower environmental concentration. Just because fish have been around longer doesn't mean that gills haven't been evolving since they first appeared.

[chikis]

It is very obvious that grasshopper has the most primitive respiratory system but according to the past question and answer booklet where I got the question from, the answer there is fish and am dragging hard to get a concrete explaination to that.

[JorgeLobo]

chikis
"The embryos (the earliest stage of and development of both plants and animals) of fish, reptile, birds and mammals are very similar and this are evidence that they evolved from a distant common ancestor. Embroyology shows that all have gill slits and tails in their embroyos like those of a fish."

The ontogeny recapitulates phylogeny concept was rejected by science a long tme ago.

Conceptually one could assume grasshopper is the most "primitive" but what are the specific comparisons?

[chikis]

@JorgeLobo,
What strong proof do you have to back the notion that grasshopper has the most primitive respiratory system?

[chikis]

For now, let me go with the crowd. I may find reason to chip in more idea in the future, maybe that will act as some kind of warmer to the thread.