Hello all,

first of all I would like to thank the owners of this board for creating such a useful bio site.

Secondly, I am having an assignment which is due tommorow and I am facing some problems in answering couple questions within the assignments so i hope anyone could be nice and give me a complete answer ASAP be4 tommorow:

1: Warm-blooded animals (birds and mammals) living in Tasmania are usually larger in size than animals of the same species living in warmer parts of Australia. Why?

2: Do you think a mammal could survive if it were the size of a mosquito? Explain.

3: Could an insect survive if it were the size of a horse? Explain. (Assume that the mammal and the insect retain their basic characteristics)


Thanks very much,

Regards,

Wassouf
XenonDesigns.Com - Owner

1 conjecture. The lack of predators due to human exploitation, including the now extinct human race that flourished in Tasmania makes this question difficult to answer. Size can help a species, specially in cold environments, to survive. Are the bats, kangaroos, spotted dicks bigger in Tasmania. Without imperial info i would say yes.

2.I would say yes if only mammals could get rid of that logical mass called the cerebral cortex.. Opps joke.. No. mammalian species rely on their brains and unless we can pack several billion neurons into a mosquito I think not.

3 Giant ants. Well given time I'm sure evolution could have found a way. Breathing is the major problem for insects. Yet it has been demonstrated that insects flex their bodies to aid in ventilation, so I would say that their only problem is competing with more advance creatures, like us.

1: I think you know the answer, larger bodies retain heat better then smaller ones.

2: The smallest mammals weigh in at less then 2grams and less then 4cm in lengh. I see nothing that prevent them anatomically for getting smaller, evolutionarily insect already have the nitch. http://www.cs.pdx.edu/~timm/dm/bumblebee.html

3: No, it would need oxygenating blood, lungs, and its exoskeleton would be far too heavy. Larges insect lived during the late Paleozoic when oxgyen levels were higher, dragon flys the size of kites, millipedes a meters long, that was about it.
http://studentwebs.coloradocollege.edu/~m_ulbrick/

1: Warm-blooded animals (birds and mammals) living in Tasmania are usually larger in size than animals of the same species living in warmer parts of Australia. Why?
because in the colder parts they need bigger bodies to hold more fat

2: Do you think a mammal could survive if it were the size of a mosquito? Explain.
No, because the amount of energy that it takes to power a mammalian body could not be gathered or held in such small body, hence the reason nothing with lungs is smaller than the hummingbird

3: Could an insect survive if it were the size of a horse? Explain. (Assume that the mammal and the insect retain their basic characteristics)
i would think not, as to get enough oxygen into such a large body would require lungs

Thanks very much,

Regards,

Wassouf
XenonDesigns.Com - Owner
i would think not, as to get enough oxygen into such a large body would require lungs

are you doing NCEA? if so post your answer sheets so that i can memorise it for next year

#3 the square-cube law prevents that. that means that if you double an animal's surface area, the mass cubes, which means that very quickly things become too large to support themselves

Yup. You can choose pretty much most of the above for your answer.

BTW I find the square-cube law very interesting. I never knew how much it would be applied to my understanding in all of science back when I first learned it in my freshman bio class, but the emphasis does extend well beyond the field of biology, such as terminal velocity in physics.

That law is also very important in why cell don’t get any bigger then half a mm, and why insect don’t get any bigger. So to supply oxygen tissues cannot get thicker then 1mm before some mean of oxygen must be provide, for insect this is done with air tubes, in mammals it is done with oxygenating blood and Myoglobin, guess which strategy is easily scalable?

2: The smallest mammals weigh in at less then 2grams and less then 4cm in lengh. I see nothing that prevent them anatomically for getting smaller, evolutionarily insect already have the nitch. http://www.cs.pdx.edu/~timm/dm/bumblebee.html


surface area to volume; there's a limit to how small a mammal can get because of heat loss over a large surface area to volume ratio precluding thermal stability. essentially, the mammal would not be able to eat fast enough to maintain body temp.

who said they would be in a environment were they could not maintain thermal homeostasis? I don’t see insects with that problem perhaps all that needed is going cold blooded.

who said they would be in a environment were they could not maintain thermal homeostasis? I don’t see insects with that problem perhaps all that needed is going cold blooded.

mammals are endotherms

and your point is?

3: Could an insect survive if it were the size of a horse? Explain. (Assume that the mammal and the insect retain their basic characteristics)

Didn't giant insects used to exist?


Giant ancient insects
They were the giant arthropods of the Carboniferous.
There were extra-large mayflies, supersized scorpions and spiders the size of a healthy spider plant. There was an array of giant flightless insects, and a five-foot-long millipede-like creature, Arthropleura, that resembled a tire tread rolled out flat.

But perhaps the most remarkable of all were the giant dragonflies, Meganeuropsis permiana nd its cousins, with wingspans that reached two and a half feet. They were the largest insects that ever lived. . .

Scientists have long suspected that atmospheric oxygen played a central role in both the rise and fall of these organisms. Recent research on the ancient climate by Dr. Robert A. Berner, a Yale geologist, and others reinforces the idea of a rise in oxygen concentration — to about 35 percent, compared with 21 percent now — during the Carboniferous. Because of the way many arthropods get their oxygen, directly through tiny air tubes that branch through their tissues rather than indirectly through blood, higher levels of the gas might have allowed bigger bugs to evolve.

http://www.cronaca.com/archives/002030.html

Maybe they weren't the size of a horse, but it is possible for insects to get bigger.

but it also says that the oxygen percent was 35% at that time, if you could go back in time and bring one to the present it would die

and your point is?
my point is that your statement;
who said they would be in a environment were they could not maintain thermal homeostasis? I don’t see insects with that problem perhaps all that needed is going cold blooded.
is incorrect, misleading, and irrelevant

but my statement clearly states "I don’t see insects with that problem perhaps all that needed is going cold blooded." hence I already mention the warm blood aspect of mammals and that perhaps to miniaturize that small a cold blood system would be needed, thus you can't read well.

but my statement clearly states "I don’t see insects with that problem perhaps all that needed is going cold blooded." hence I already mention the warm blood aspect of mammals and that perhaps to miniaturize that small a cold blood system would be needed, thus you can't read well.
i realize you're not a biologist, which is why I included what you did not know, the importance of surface area to volume in the limitations of small size in mammals

Didn't giant insects used to exist?


http://www.cronaca.com/archives/002030.html

Maybe they weren't the size of a horse, but it is possible for insects to get bigger.
upper size limit in insects is due to their lack of a circulatory system, i.e. they rely on diffusion for O2 distribution.

But I obviously knew it as I wrote it down. Perhaps people that are not Biologist might know something about biology?

But I obviously knew it as I wrote it down. Perhaps people that are not Biologist might know something about biology?
you said;
The smallest mammals weigh in at less then 2grams and less then 4cm in lengh. I see nothing that prevent them anatomically for getting smaller
obviously there is something, i.e. surface area to volume ratio and the problem of heat retention and endothermal stability for bodies too small.

Really what if this hypothetical micro-mammal lived under the skin of other endotherms? What if it lived in hot tropical environments or in places were temperatures don't vary much? Being warm blooded is not a anatomical trait by the way.

Really what if this hypothetical micro-mammal lived under the skin of other endotherms? What if it lived in hot tropical environments or in places were temperatures don't vary much? Being warm blooded is not a anatomical trait by the way.

mammalian metabolism constrains them to endothermy no matter where they live, thus it constrains their size due to the surface area to volume ratio I mentioned.

I'm glad I could teach you something no matter how reluctant a student you are.

Look at question 2 in the original post thread starter, then answer it with what you know and what i've taught you.

No it doesn't: they would not be losing heat if the environment matches their body temperature, no matter how little volume they have. You have yet to prove that a mammal at the size of mosquito would not be able to maintain it metabolism. Also who said they need to remain endotherms? We could say it hibernates in low temperatures for example.

your a pretty bad teacher, haven't tought me anything, your also delusion for beleive you have.

No it doesn't: they would not be losing heat if the environment matches their body temperature, no matter how little volume they have. You have yet to prove that a mammal at the size of mosquito would not be able to maintain it metabolism. Also who said they need to remain endotherms? We could say it hibernates in low temperatures for example.

your a pretty bad teacher, haven't tought me anything, your also delusion for beleive you have.
well, it's obvious that english is not your first language. what is your native tongue?

there's obviously a communication breakdown that is limited by your ability to speak and understand english.

you have yet to answer question number 2. do your research there, and i'll have done my job in teaching you, the reluctant student.

I have answered question two, it you that seem to have the mental laps in noticing.

I have answered question two, it you that seem to have the mental laps in noticing.
i know you think you did, but you didn't.

but allow me to kick your ass once again.

Proc Natl Acad Sci U S A.*1995 August 1;*92 (16): 7317–7321
Bioenergetic Scaling: Metabolic Design and Body-Size Constraints in Mammals
GP*Dobson and JP*Headrick
Department of Molecular Sciences, James Cook University of North Queensland, Townsville, Australia.
*Abstract*
*

The cytosolic phosphorylation ratio ([ATP][ADP][Pi]) in the mammalian heart was found to be inversely related to body mass with an exponent of -0.30 (r = 0.999). This exponent is similar to -0.25 calculated for the mass-specific O2 consumption. The inverse of cytosolic free [ADP], the Gibbs energy of ATP hydrolysis (DG'ATP), and the efficiency of ATP production (energy captured in forming 3 mol of ATP per cycle along the mitochondrial respiratory chain from NADH to 1/2 O2) were all found to scale with body mass with a negative exponent. On the basis of scaling of the phosphorylation ration and free cytosolic [ADP], we propose that the myocardium and other tissues of small mammals represent a metabolic system with a higher driving potential (a higher DG'ATP from the higher [ATP/[ADP][Pi]) and a higher kinetic gain {(DV/Vmax)/D[ADP]} where small changes in free [ADP] produce large changes in steady-state rates of O2 consumption. From the inverse relationship between mitochondrial efficiency and body size we calculate that tissues of small mammals are more efficient than those of large mammals in converting energy from the oxidation of foodstuffs to the bond energy of ATP. A higher efficiency also indicates that mitochondrial electron transport is not the major site for higher heat production in small mammals. We further propose that the lower limit of about 2 g for adult endotherm body size (bumblebee-bat, Estrucan shrew, and hummingbird) may be set by the thermodynamics of the electron transport chain. The upper limit for body size (100,000-kg adult blue whale) may relate to a minimum D¢ATP of ?55 kJ/mol for a cytoplasmic phosphorylation ratio of 12,000 M-1.

That still does not stop it from living in a suitable environment. Nor does that stop a semi-endothermic or exothermic organism evolving from a mammal. And to top it of your article does not prove that mammals can not go below 2g.

That still does not stop it from living in a suitable environment. Nor does that stop a semi-endothermic or exothermic organism evolving from a mammal. And to top it of your article does not prove that mammals can not go below 2g.

Ha Ha!! I kicked your butt AGAIN!!!!!!!

You just too cowardly to admit it. But don't worry about it. I'm much more educated than you. Of course I'll know more about biology. The only thing is that now you have to admit it.

paulsamuel,

You really have a childish superiority complex there, what not enough respect at work? Students laughing at you? small penis? Had to call in sick today to get away from it all to go and hagel me on sciforums? Sorry but I don’t pity your immaturity enough to give you the satisfaction you so crave. You have also not made a valid argument to my previous post, running out of bullet are you? :rolleyes: I already have you reduced to a childish "I win, you lose" thats enough to make my cry with laughter.

paulsamuel,

You really have a childish superiority complex there, what not enough respect at work? Students laughing at you? small penis? Had to call in sick today to get away from it all to go and hagel me on sciforums? Sorry but I don’t pity your immaturity enough to give you the satisfaction you so crave. You have also not made a valid argument to my previous post, running out of bullet are you? :rolleyes: I already have you reduced to a childish "I win, you lose" thats enough to make my cry with laughter.
this is the very reason you should not be allowed to moderate. i.e. you can't admit when you're wrong, and you'll abuse your power to silence those who expose the crap you spread around here.

fortunately most people see you for who you are, a fraud who pretends to be educated

and when did I abuse my power to silence people? paulsamuel I think your changing this thread from what it was about (you remember what it was about don't you?) to this endless arguing about how much you hate me. You seem to do that to a lot of threads. and a “fraud who pretends to be educated”, perhaps you should look in the mirror: I'm not the one going around trying to prove people wrong with my superiority complex. I’m not saying “hey I’m a phd I must be right, your wrong” with this appeal to authority fallacy. Your attempts to gain authority here make you look like a very little man with deep problems.

and when did I abuse my power to silence people? paulsamuel I think your changing this thread from what it was about (you remember what it was about don't you?) to this endless arguing about how much you hate me. You seem to do that to a lot of threads. and a “fraud who pretends to be educated”, perhaps you should look in the mirror: I'm not the one going around trying to prove people wrong with my superiority complex. I’m not saying “hey I’m a phd I must be right, your wrong” with this appeal to authority fallacy. Your attempts to gain authority here make you look like a very little man with deep problems.
i made a statement, a very simple statement, but your ego could not accept that anyone could know more than you or that you could be wrong

i made a statement, a very simple statement, but your ego could not accept that anyone could know more than you or that you could be wrong

Heck I was going to say the very same thing about you. :D