14.12.2016 – A trip in the afternoon
December 16, 2016
September
December 18, 2016
Fish have vertical tail fins, while whales and dolphins have horizontal ones. Why is that? These traits are probably the result of the evolution of locomotion. Fish derive from wormy creatures that slithered over the sea floor. This made it crucial to have vertical tails that moved from side to side.
Marine mammals derive from land mammals that walked on four limbs. These animals move by flexing the spine up and down. The surrounding muscles devloped to aid this movement. Marine mammals move in the same way as these four-limbed land animals: dolphins and whales swim by moving their tail fin and rear body up and down, and the surrounding muscles support this movement.
by Judith Kok
4 Comments
[…] Dolphin tails vs fish tails […]
Why don’t you tell it like it truly is. The evolution of the whale and Dolphin Tail is a theory, not a fact, that they came from four-legged land mammals. I wish you “scientists” would tell the truth where your theories are concerned.
It’s not like the Bible says theory behind every origin riddle it throws, either. If someone believes in evolution, they are free to not call it a theory. How do you explain the fossil evidence leading up to losing hindlimbs and gaining a more upwards nostril? Which now is the blowhole?
No it’s a fact. Under all that fishy fat flesh and flapping fins, their skeletons are just like ours: They have shoulder blades, wrists, and even knuckles.