للاستئناس ولا ادري ان كان ذات النظام يعمل مع الانسان:
طولها الآن:
Millipedes range from 2 to 280 millimetres (0.079 to 11 in) in length, and can have as few as eleven, to over a hundred segments.
ولكنه كان:
In the Upper Carboniferous (340 to 280 million years ago), Arthropleura became the largest known land invertebrate of all time, reaching lengths of up to 2.6 metres (8 ft 6 in). Millipedes, centipedes, and other terrestrial arthropods attained very large sizes in comparison to modern species in the oxygen-rich environments of the Devonian and Carboniferous periods, and some could grow larger than one metre. As oxygen levels lowered through time, arthropods became smaller in size.
انتقلت من 2 سم إلى 2 متر!!! أي 200 سم! أي 100 ضعف!!!
المعلومات ويكي وهنا:
http://news.nationalgeographic.com/n...t-insects.html
A higher concentration of oxygen in the atmosphere let dragonflies sometimes grow to the size of hawks, and some millipede-like bugs reached some six feet (two meters) in length, a new study suggests. (Related: "Dragonflies Migrate Like Birds, Study Says" [May 10, 2006].)
Now that the proportion of oxygen has decreased, however, bugs can't grow much larger than they do now, the authors write.
The reason: The bigger an insect, the bigger the proportion of its body devoted to its tracheal system, which functions like a lung but is far less efficient at large sizes.
"[The tracheal system] explains why they are small," said study co-author Jon Harrison, a professor of environmental physiology at Arizona State University. "It takes up all the room."
The study appears this week in the journal Proceedings of the National Academy of Sciences
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