Definitions should ideally be based on how they are intended to be used. That’s partly why bacteria are defined based on base-pair differences, birds are defined mostly by appearance, and humans are not split into subspecies.
I agree with your overall article. The definition of ‘species’ is broken and ridiculous. But I think trying to find the final form of the Definition of Species is a lost cause and missing the forest for the trees. Instead, I think it’s better to move towards allocating conservation effort based on the phylogenetic tree and evolutionary distinctiveness. (Really this is a proxy for preserving traits of living things: everything that might potentially be important or interesting about life!) There has been remarkably little progress on doing this. At least the global biodiversity framework has recognized evolutionary distinctiveness as a “complimentary indicator”, and EDGE is working on it. Instead of fixing the way we define species and subspecies, skip the lumpers and splitters problem entirely and allocate resources based on the evolutionary distinctiveness itself. (An easy single number, capturing the proportion of the tree if life it represents!) If the species are totally unique, isolated, and represent a huge branch of the tree of life, then they should be prioritized and get more resources than another random species. And certainly compared to the the split-to-all-hell island anoles. Creating a new species would just… split the resources in half… as they should be? It just seems pretty self evident to me that this is the way to coordinate and prioritize species conservation.
It does get complicated when you compare between beetles and mammals of equal distinctiveness, but at least the phylogenetic difference is objective and then you can pile on the human favoritism explicitly on top. There may be also be some species that evolve faster than others, but favoring those doesn’t seem terrible or like it will be a huge problem afaik.
Hi David!
Definitions should ideally be based on how they are intended to be used. That’s partly why bacteria are defined based on base-pair differences, birds are defined mostly by appearance, and humans are not split into subspecies.
I agree with your overall article. The definition of ‘species’ is broken and ridiculous. But I think trying to find the final form of the Definition of Species is a lost cause and missing the forest for the trees. Instead, I think it’s better to move towards allocating conservation effort based on the phylogenetic tree and evolutionary distinctiveness. (Really this is a proxy for preserving traits of living things: everything that might potentially be important or interesting about life!) There has been remarkably little progress on doing this. At least the global biodiversity framework has recognized evolutionary distinctiveness as a “complimentary indicator”, and EDGE is working on it. Instead of fixing the way we define species and subspecies, skip the lumpers and splitters problem entirely and allocate resources based on the evolutionary distinctiveness itself. (An easy single number, capturing the proportion of the tree if life it represents!) If the species are totally unique, isolated, and represent a huge branch of the tree of life, then they should be prioritized and get more resources than another random species. And certainly compared to the the split-to-all-hell island anoles. Creating a new species would just… split the resources in half… as they should be? It just seems pretty self evident to me that this is the way to coordinate and prioritize species conservation.
It does get complicated when you compare between beetles and mammals of equal distinctiveness, but at least the phylogenetic difference is objective and then you can pile on the human favoritism explicitly on top. There may be also be some species that evolve faster than others, but favoring those doesn’t seem terrible or like it will be a huge problem afaik.
To read some more of my musing on this—check out my article for EcoResilience Initiative here.