Fish are so abundant in the ocean (even given how humans overfish, and them often being prey), I kind of wonder
1. Why don’t marine animals converge to a more fish like form? (Aside from say land mammals like whales and dolphines who decided they want to go to the sea)
2. What benefits are there in having a fish-like form in the ocean? It must be evolutionarily advantageous for some reason.
3. Did the first non microscopic multicellular beings have fish-form?
In: Biology
So first we have to define what we mine by “fish-form”. I going to with definition “streamlined body with short fin-like limbs” with this broad definition we have plenty of spieces that have developed more streamlined bodies similar to what fish have.
1. Invertebrates have different enough body structures that evolving into fish like form makes no sense, since fish take advantage of spine for their mobility. For vertebrates you could easily argue that they actually have as far as creating, streamlined bodies suited for swimming. This is definitely true for mammals (Whales and Seals) and birds (penguin). It has been true for dinosaurs as well and you could argue it has happened for example to sea turtles (they are streamlined and feet have developed into flippers though obviously shell isn’t very fishlike) and in amphibians axolotl is example of spieces which has taken more fish like form by not going through metamorphosis.
2. Well in short good mobility in water. There used to be fish with armor plating but they have died out.
Latest Answers