that’s fine. you want to talk only about evoluation that happens over many generations from one multicelluar animal ancestor to multicelluar descendants. you don’t want to talk about evoluation that happens in a single generation from one multicellular animal parent to a unicellular child. got it.
Huh? “breaking off of the main body” is the process by which unicellular organsims reproduce. so i don’t understand why you’re hung up on this.
Nope, not in the science I’ve learned. Even in fission, the broken parts had better have the entire genome.
Your leap from the “lower” vertebrates (including some that do undergo metamorphosis, with different genes expressing at different times in different environments) toward those that seem simpler, yet still retain unexpressed DNA of more complex life programs, doesn’t fit with what we know. May I suggest immersion in a good developmental biology course of study? The presence of vestigial and intermediate organs and body parts in the course of evolution may be of especial interest to you.
it is an interesting question, like can transmissible tumour be classified as separate organism? is transmissible tumour from mammal still a mammal? I would say no, because it lacks defining traits of mammals.
There is something else somewhat related to this I thought of as well. There are some arthropods (and presumably other non-vertebrates) that are born/hatch already sexually mature. Could this be possible to evolve in vertebrates?
Huh, what??? Holy crap. There is actually a mammal that reaches sexual maturity prior to its weaning period. Didn’t think that was even physically possible
Remember that horrific case in Peru some years ago? Five-year-old gave birth? That was extremely outside the biological norm for our species, but it shows how limits can be pushed, even if only rarely.