Now- a bit of insect maths

[Wild-Woman]

Pay attention! Sit up- and STOP fiddling.


The combined weight of all ants in the world= the same weight of all human beings.


Show me how you would calculate this.


PS-If you persist in talking to your neighbour- leave the room please.

[Lord V]

Not sure there are any accurate estimates of ant numbers but there are some figures here Answers.com - How many ants are there in the world
figure of average weight given as 3mgs per ant

Brian v.

[pressld2]

Jules, you really know how to appeal to the obsessive-compulsive in me, don't you!

Taking Brian's research into the average weight and estimated population of ants, and doing my own research into the current world human population and average weight I have come up with...

Ants
Average weight in Kgs - 0.000003
Estimated population - 10,000,000,000,000,000
Multiply together for total weight = 30,000,000,000 (30 million metric tonnes)

Humans
Average weight in Kgs - 65
Estimated population - 6,880,700,000
Multiply together for total weight = 447,245,500,000 (447 million metric tonnes)

So my calculations show the weight of all humans to be nearly 15 times greater than the weight of all ants.

Please miss, NOW may I go to the toilet?

Dave P.

[jaguarondi]

Originally Posted by Wild-Woman

The combined weight of all ants in the world= the same weight of all human beings.


Show me how you would calculate this.

You don't have to - Wikipedia have done it for you. See -
http://en.wikipedia.org/wiki/Biomass_(ecology)

[Wild-Woman]

Originally Posted by pressld2

Jules, you really know how to appeal to the obsessive-compulsive in me, don't you!

Taking Brian's research into the average weight and estimated population of ants, and doing my own research into the current world human population and average weight I have come up with...

Ants
Average weight in Kgs - 0.000003
Estimated population - 10,000,000,000,000,000
Multiply together for total weight = 30,000,000,000 (30 million metric tonnes)

Humans
Average weight in Kgs - 65
Estimated population - 6,880,700,000
Multiply together for total weight = 447,245,500,000 (447 million metric tonnes)

So my calculations show the weight of all humans to be nearly 15 times greater than the weight of all ants.

Please miss, NOW may I go to the toilet?

Dave P.

Well done Dave.
I'm glad to see the grey matter still has it!

[pressld2]

Interesting, Wikipedia have the average weight of a human as 15Kg less than I used. But even more significant they give the average weight of an ant as 100 times more than Brian did.

Using these figures we get...

Ants
Average weight in Kgs - 0.0003
Estimated population - 10,000,000,000,000,000
Multiply together for total weight = 3,000,000,000,000 (3 billion metric tonnes)

Humans
Average weight in Kgs - 50
Estimated population - 6,880,700,000
Multiply together for total weight = 344,035,000,000 (344 million metric tonnes)

So now, all the ants weigh about nine times as much as all the humans.

And that's using the lower estimate for the ant population of 10 to the seven.

Dave P.

[Wild-Woman]

Which just goes to show that you shouldn't believe everything that's put on the net!

[poschiavanus]

Fascinating. I think the original numbers come from the work of E.O. Wilson and relate to ant biomass in tropical rainforests. The figure which stuck in my mind was 8% of animal biomass. There's more at Google Answers: Biomass of insects.

It's worth sense checking the notional weight of an ant. My notional ant is a cylinder 10mm long and 5 mm in diameter, and therefore has a volume of 1.9635 x 10-7 cubic metres, which is 0.000196 litres or 196 microlitres. If we assume an ant weighs close to its volume in water this gives a weight around 200 micrograms. So PressId2's second value looks a better choice. [Disclaimer, place of decimal point not fully checked.]

The average weight of humans is also probably still too high. The human population figures contain a very large number of children (in some countries the median age is in the high teens), and I suspect the wikipedia figure relates to adults.

[pressld2]

Originally Posted by poschiavanus

The average weight of humans is also probably still too high. The human population figures contain a very large number of children (in some countries the median age is in the high teens), and I suspect the wikipedia figure relates to adults.

My initial research on average human weight only turned up figures for average male and female weights in various countries and these ranged from 65-75 Kgs for women and 75-90 Kgs for men. I just picked the bottom of the range for two reasons. One, because the most populous contries (China and India combined account for over one third of the world population) tend not to have obesity problems and the people there are generally smaller overall. Two, to allow for children. But it seems I didn't allow enough and the 50Kg figure is a much better one although possibly still too high.

Dave P.

[Klaas Reißmann]

That only shows what we say in Germany: I only trust in the statistics I counterfeited by myself.

Regards
Klaas