2006-08-19 09:30:51 · 4 answers · asked by SANTANU P 1 in Science & Mathematics ➔ Zoology
At it's simplest level, a phylum is a body plan.
The chordate is one answer, but there are plenty of others around.
Arthropods put the skeleton on the outside and jointed the limbs.
Platyhelminthes didn't bother with a skeleton
and so on
2006-08-19 10:02:51 · answer #1 · answered by Anonymous · 0⤊ 0⤋
Its because during evolution there was abundant life on earth which was simple and its also required becouse larger the basic stock larger will be the chances of having variable organisms.If the stock of the lower non chordates is low or with lesser numbers there will be lesser chances of formation of organisms with larger variations.The large varity of organisms available today is just due to the large no.of lower stocks available in the begning.
2006-08-23 00:01:05 · answer #2 · answered by Tazinder Singh 1 · 0⤊ 0⤋
Some people think having more phyla means the group is more successful in natural selection, but maybe not. It's probably more important what the number of organisms is. Anyway, the environmental pressures the group has experienced will affect how diversified it becomes,so the number of phyla you get will relate to the environmental diversity the group has survived.
2006-08-19 16:36:58 · answer #3 · answered by Lorelei 2 · 0⤊ 0⤋
to give strength and support to body
2006-08-23 14:16:32 · answer #4 · answered by doctor asho 5 · 0⤊ 0⤋