It’s a thing that has ticked me off and that i often see on wikipedia or scientific papers when reading about extinction events.
There’ll often be sentences like: “Earth’s largest extinction killed 57% of all families, 83% of all genera and 90% to 96% of all species”
Does the “all species” mean that 90% of biologically different species died, or that 90% of individuals died?
In: 1
It means biologically different species. So if there were 100 different species of animals, 90 of them were wiped out.
species. We don’t have great ways to estimate the number of individuals of a species on earth in the past (other than seeing that, say, Species A shows up a lot more than Species B), but we can more easily count how many *species* are found before a line in the rock but not after.
For a species to go extinct means that no breeding population survived, *anywhere.* So if 90% of all species were killed, you can bet that nearly 100% of individual organisms were killed. The other 10% of species scraped by, with a relative handful of survivors.
> According to the genetic bottleneck theory, between 50,000 and 100,000 years ago, human populations sharply decreased to 3,000–10,000 surviving individuals.[35][36]
https://en.wikipedia.org/wiki/Toba_catastrophe_theory#Genetic_bottleneck_theory
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