3 ms·
>While virtually no male elephants are tuskless (they need tusks to fight), about 2 percent of female elephants are naturally tuskless. Among female elephants i
by JBiserkov 10y ago
>While virtually no male elephants are tuskless (they need tusks to fight), about 2 percent of female elephants are naturally tuskless. Among female elephants in Gorongosa who were adults during the civil war, however, half are tuskless — the others were simply killed. But tusklessness is an inheritable trait. That means that, even though poaching levels have fallen, a third of Gorongos’s young female population is tuskless today.
I think the correct term is survivor bias.
Update re downvotes: The title literally says "Elephants without tusks are a response to the selective pressure of poaching".
The body text says "2% of female elephants are naturally tuskless" (emphasis mine).
So "Elephants without tusks" per se are natural.
"(Massive) Increase in % of tuskless offspring as a result of selective killing of tuskfull adults (given that tusklessness is an inheritable trait)" seems like a more accurate, yet obvious (almost tautologically so) observation. It seems to be true when the trait is inheritable and strongly discriminated against - the children of the survivors look more like the survivors than those who were killed because they (the killed) were different. You don't say!
- r00fus 10y agoI think your correction is mistaken. Survivor bias is a logical error [1]. This sounds like natural selection with human activity acting as a selection factor. "[Survivor Bias] is the logical error of concentrating on the people or things that "survived" some process and inadvertently overlooking those that did not because of their lack of visibility. [1] https://en.wikipedia.org/wiki/Survivorship_bias https://en.wikipedia.org/wiki/Survivorship_bias
- foreigner 10y agoEvolution is the ultimate survivor bias :-)
- hexane360 10y agohttp://www.nature.com/scitable/definition/evolution-78 http://www.nature.com/scitable/definition/evolution-78 >Microevolution reflects changes in DNA sequences and allele frequencies within a species over time. Allele frequencies changed from ~2% to ~33%. Mutations are not necessary for the process, unless the allele is at 0% frequency to begin with.
- pix64 10y agoNaturally meaning born without.
- JBiserkov 10y agoYes.
- SapphireSun 10y agoNaturally occurring mutations / variants are the raw material for natural selection. Nothing contradictory about that. :)