Much here has been said about the use of paraphyletic groups like fish and reptile. I think paraphyletic groups can have use when they describe a coherent eco-physiological grade of animals.
What we call reptiles for example are ectothermic, have scales, sprawling limbs (if they have limbs) and most lay eggs. What we call fish have fins, gills, a lateral line, are entirely aquatic.
But what of invertebrate? I think the term invertebrate unlike fish or reptile has no use. There is absolutely nothing that unites so called invertebrates ecologically, morphologically, physiologically, or developmentally. The only thing they have in common is metazoan features they also have in common with vertebrates, and I guess being ectotherms which they also have in common with most vertebrates.
So, I guess here is the question. Would anything be lost if we retired the term “invertebrate”?
Referring to non arthropod animals, just as the use case for invertebrate is referring to non vertebrate animals. But this begs the question, is referring to non vertebrate animals of any more utility than referring to non arthropod animals?
absolutely. i’ve never had the urge to talk about non-arthropod animals as a collective group. but i do often talk about non-vertebrate animals as a group, and apparently some folks write entire books about them, too.
Inarthropods lack a sclerotized chitin exoskeleton. Inechinoderms lack a water vascular system. Inporifierans lack spicules and spongin. The lack of a spinal column is not some more essential character than lacking an exoskeleton, water vascular system, or spicules
Except there are way more mammalogists, ornithologists, herpetologists, and ichthyologists than malacologists. American land grant universities have entire colleges devoted to wildlife, which generally means vertebrate game animals. There is a major distinction in terms of research (culture, ethics, funding, etc.) with invertebrates vs. vertebrates. So at least legally/practically in the US it is a very useful term. Whether that is helpful on a biological level may be different. Although ecologically vertebrates seem generally different from invertebrates at least in terms of size, which has lots of other ecological ramifications.
And how many entomologists, carcinologists, arachnologists and myriapodologists compared to them?
This was the crux of my question
There is substantial size overlap between vertebrates and many other groups of animals. So much so that arthropod predation on vertebrates is quite common
Legally, practically, and culturally there is a clear vertebrate/invertebrate distinction. Humans make categories that don’t always line up with monophyletic groups.
Well sure, but that doesn’t really matter for median size. And you have to think about the sorts of animals that humans consciously interact with (or used to interact with) on a daily basis, not just what is technically out there. Language is based on human experience, not objective reality.
I’ll admit I don’t have numbers on me but there are a lot of entomologists alone
I was pretty much coming at this from a biological angle. But sure, lets go with this. What would be the consequences of ditching the term invertebrate in this regard?
People absolutely regularly encounter many non-vertebrates on a regular basis. Many insects and spiders are extremely common, and many aquatic non-vertebrates are also regularly encountered depending on one’s location. The average person in most areas has definitely seen flies and probably snails too
Yes, but invertebrates are nowhere near as culturally important as vertebrates (food, pets, rituals, etc). I’m arguing these are potentially useful scientific categories for culturally important distinctions. Of course people do eat invertebrates and keep them as pets, etc., but I’m talking about generalities here.
It is true that in a vague general sense vertebrates are more culturally significant than arthropods. But I would then argue arthropods are more significant than annelids or mollusks, which are in turn more significant than echinoderms which are more significant than rotifers. Invertebrate is a completely incoherent category. For that matter, vertebrates aren’t necessarily all culturally important either. Monarch butterflies, lobsters and even scorpions have immensely more cultural significance than caecilians, chimaeras, or colugos
In my state and probably others, the term “wildlife” under state law refers only to vertebrates plus crustaceans and mollusks (the “inverts”). That leaves out a lot of animals that the state wildlife agency doesn’t fund, manage, or do research on. Not saying that’s appropriate, it’s just a reflection of history and where the priorities lie (e.g., consumptive use of a resource). That bias is changing although slowly.