2006-12-25 13:20:16 · 5 answers · asked by gtarplyr98 1 in Science & Mathematics ➔ Biology
. Fish all evolved from an ancestor which happened to move by side to side undulation. Some non-mammalian marine animals move bu up and down undulation. The fact that a left to right undulator advanced to the point of being able to lift itself from the water may have been purely a matter of chance.
. Sea mammals evolved from land mammals. Land mammals, when running, are working against gravity to propel their bodies off the ground with each stride. They attain their highest speeds when the front feet work in unison and the rear feat work in unison. They thus evolved with musculature and a spine design designed to develop strong forces in their back (to reach forward to plant their front feet while pushing off with their rear legs) and in their stomachs (to draw the rear legs forward for the next stride while pushing back with their front feet).. This spinal structure and musculature went with them when some mammals took up residence in a watery environment.
2006-12-25 13:46:54 · answer #1 · answered by PoppaJ 5 · 2⤊ 0⤋
suited question for evolutionist: this means that some the area in time, there grew to become a sea dweller with a diagonal tail fin, OR a creature "stepped forward" from a water dweller precise right into a land goer, and then desirous to bypass decrease back into the water, the two way. somebody is swimming in circles....
2016-11-23 17:08:17 · answer #2 · answered by lucy 4 · 0⤊ 0⤋
Perfect question for evolutionist: this means that some where in time, there was a sea dweller with a diagonal tail fin, OR a creature "evolved" from a water dweller into a land goer, and then decided to go BACK into the water, either way. someone is swimming in circles....
2006-12-26 08:22:10 · answer #3 · answered by WHAT?!!! 2 · 0⤊ 0⤋
Since sea mammals once lived on land their spine had to become stronger in the "up and down" dirrection to resist gravity. Then when they moved back to the sea they retained the stronger "up and down" mussles. Fish who have never had to fight against gravity all swim side to side.
2006-12-25 13:26:11 · answer #4 · answered by Anonymous · 1⤊ 0⤋
Now theres one I have never thought of...
Interesting to hear responsible peoples comments on this and not those from jack asses that say stupid things
2006-12-25 13:42:20 · answer #5 · answered by Bridget 3 · 0⤊ 1⤋