Research Year 11 Biology (Question on Animal Size)

[Wassouf]

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

[JaKiri]

3 is the only one I could answer with any certainty, with justification.

 

And the answer is 'no'. Insects don't have circulatory systems, they get oxygen to, and waste gasses from, their cells by just having holes in them (effectively). This is highly inefficient for anything but the smallest creatures, hence the need for blood vessels and the like in larger critters. Furthermore, if you just scaled them up, their structure wouldn't be able to take the weight (look at a relative comparison between a fly's leg and an elephant's leg, compared to their bodies, for instance), and they'd collapse, although that's not about insects per se, that's about scaling ANYTHING up.

[5614]

1:) The reason for that is because in a cooler country such as Tasmania the animals need a fat supply to keep them warm, where as in a cool country the animal wants and needs to loose heat so it has very little fat, as fat acts as an insulator

 

2:) if the mamal was small it wouldnt survive because its prey and food supply are much bigger than it would be. I mean, imagine a tiger eating a deer, if it was the size of a fly...... it wouldnt work!

 

3:) an insect the size of a horse would not survive because, flies have exo-skeletons, their skin is like their bones, if they were the size of a horse then they would be massively heavy, probably too heavy to keep themselves standing.... but other than that im not sure

[5614]

there you go, read JaKiri for Q.3

[Radical Edward]

Hello all' date='

 

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?

 

this is probably a combination of things, and I am not familiar with tasmanian fauna, so I will give you a couple of answers, both maintaining natural selection at their core, which is an important focus in issues like this.

 

Larger animals have a smaller surface area to mass ratio. this means that smaller animals lose heat more quickly than larger ones, and hence smaller animals need to burn more energy than larger ones in order to maintain their body temperature. (Imagine this kind of like a cake. If you heat a cake up to 200 degrees, and then chop it into pieces, it will cool much more rapidly than a cake which is left whole). When food supplies are short, those animals that can stay the warmest most easily are more likely to survive and pass their genes for larger size onto the next generation, creating an evolutionary pressure for larger sizes. Another issue might be that of body fat, which is an insulator. This has the same effect as above but with the added insulation properties of fat meaning that animals which store fat more readily will be more likely to survive and pass on their genes.

 

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

no, as above, they would lose their heat extremely quickly and would probably not be able to maintain their internal body temperature without eating so often that they would probably just be an obligate parasite. About the only possibility would be if the mammal actually lived on or inside another organism. There are other issues involved though, such as the size of the organs. mammals have a much more complex internal structure than insects, with lungs kidneys, a spleen, liver heart and so on, and it is not likely that these could be shrunk to that size and still function adequately. There would also be issues with giving birth, again the placental structure is very complex, and the foetus would have to be absolutely microscopic. I doubt that there could be any youth stage since the foetus probably could not grow any larger than a blastocyst before it has to be born!

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)

[/b]

 

if maintaining it's basic characteristics, probably not, no. Others have already made points such as the lack of lungs and so on meaning that they could not breathe properly, and again, because they have no method for maintaining their internal body temperature, it would take alot of heat to keep them warm. the largest insect that I know of is Meganeura of the order Protodonata (related to dragonfly) from the Permian period with a wingspan of 70-75cm.

 

http://www.palaeos.com/Invertebrates/Arthropods/Insecta/Protodonata.html

[Radical Edward]

moderator note:

 

I changed the name of the thread to make it a bit more useful

 

Radical Edward

[Wassouf]

Guys all of you who answered my question you really did make my day, I didnt expect a reply in that quickness. If you dont mind me asking 2 more questions cuz you gave me a highly scientific replies answers:

 

- Wedge-tailed eagles spend long periods high in the air during the day, often circling around in rising currents of air, with barely any movement of their wings. The birds are large - up to 2.5m from wingtip to wingtip and weighing several kilograms. They are often seen at higher altitudes than light aircraft. Most other bieds (eg. magpies, honey-easters, kookaburrus) are quite unable to reach such heights. Nor can they stay aloft for over an hour at a time. Compare the flight of an eagle with that of a bat and that of a sugar glider.

 

1- What kind of flight is each? (flipping, gliding, soaring, etc)

2- What speical advantages (if any) might the eagle's type of flight have for it?

 

after answering this question I would be finishing all my assignment from you guys ..

 

 

Regards,