the.com/species

Nature's blurry boundary line that refuses to stay where biologists draw it

means A category of living things whose members can typically breed with one another, forming the basic unit biologists use to sort the diversity of life.

from From Latin 'species,' meaning 'a seeing, sight, appearance, kind,' built on 'specere,' to look — a cousin of 'spectacle,' 'inspect,' and 'spy.' The root idea is that a species is what something looks like, the visible 'kind' of a thing. It entered English by the 1300s as a logical term for a class within a wider 'genus,' and only later was drafted into biology to name nature's living types — ironic, since species turn out to be far harder to see clearly than the eye-rooted word suggests.

count unknown
Maybe 8 million exist; we've named under 2 million
no clean rule
Over 26 competing definitions, none fully works
ring species
Neighbors interbreed, but the ends cannot
daily births
Roughly 18,000 new species described each year
vanishing fast
Extinctions running thousands of times the natural rate
the.com · every word