Animals are a specific lineage of eukaryotic multicellular (mostly) organisms that lack cell walls.
The problem with evolution is that it likes to make exceptions to any descriptor based taxonomy. Any taxonomic category will ultimately be attempting to say “this genetic lineage”. If a sea sponge species eventually develops chlorophyll and cell walls it’ll still be an animal, but just a really fucking confusing one.
Yep, traditional (non-phylogenetic) taxonomy creates problems like protists, the grab bag of eukaryota.
There are more species labeled protists than the sum of all their descendants.
Are they animals, plants, or fungi? Sure, why not!
Some are heterotrophs (eat things), some are autotrophs (energy from sun or chemicals), and others are mixotrophs (some of both). Some are motile, others immotile. Some are multicellular, most unicellular.
The problem is all taxonomy is arbitrary, and traditional taxonomy is pretty inconsistent. Phylogenetic taxonomy is still arbitrary, but using evolutionary relationships instead of “this monkey looks like other monkey” at least gets you more consistency in that system.
Before they attach to a rock they move around in a larval stage, same for anemones and some jellyfish species. There are exceptions to all of our classifications because nature doesn’t have to play by any rules besides physics. Even the concept of species has no set definition because no matter what we come up with there are exceptions. Also “seek out” was a bit too specific, they have to take in food from outside themselves as they can’t make their own energy like plants.
Sea sponges are animals and don’t move.
Animals are a specific lineage of eukaryotic multicellular (mostly) organisms that lack cell walls.
The problem with evolution is that it likes to make exceptions to any descriptor based taxonomy. Any taxonomic category will ultimately be attempting to say “this genetic lineage”. If a sea sponge species eventually develops chlorophyll and cell walls it’ll still be an animal, but just a really fucking confusing one.
Yep, traditional (non-phylogenetic) taxonomy creates problems like protists, the grab bag of eukaryota.
There are more species labeled protists than the sum of all their descendants.
Are they animals, plants, or fungi? Sure, why not!
Some are heterotrophs (eat things), some are autotrophs (energy from sun or chemicals), and others are mixotrophs (some of both). Some are motile, others immotile. Some are multicellular, most unicellular.
The problem is all taxonomy is arbitrary, and traditional taxonomy is pretty inconsistent. Phylogenetic taxonomy is still arbitrary, but using evolutionary relationships instead of “this monkey looks like other monkey” at least gets you more consistency in that system.
I wish we could use photosynthesis, even if it’s just as a supplement like a hybrid vehicle.
I know some folks who spend their time in Brinstar who’d like a word.
Before they attach to a rock they move around in a larval stage, same for anemones and some jellyfish species. There are exceptions to all of our classifications because nature doesn’t have to play by any rules besides physics. Even the concept of species has no set definition because no matter what we come up with there are exceptions. Also “seek out” was a bit too specific, they have to take in food from outside themselves as they can’t make their own energy like plants.
Paralyzed people too
But that’s due to some sort of injury or disorder, not how they function standard.