What is chase-away selection?
In preparation for answering this question I dipped my toes back into the cesspool of sexual selection theories and MAN is it just a hot sweaty mess. Utterly fascinating, of course, but just a mess.
Ok, so chase-away selection theory. To understand where it comes from, you’ve got to understand a few basic things about sexual selection itself.
It is common knowledge that large dog breeds tend to have shorter lifespans (generally around 10-13 years; for the wolfhound and the great dane, as low as 7-8 years) than smaller dog breeds (some of which can go on for as long as 15-20 years). In fact, one study found that within 74 different breeds, dogs lose about one month of life expectancy per 4.4 pounds (2 kg).
So why does this happen?
This is an interesting and complex question.
A fellow named Dollo says no, and in 1893 he proposed a law- Dollo’s Law, in fact- that stated that once lost, genetic traits could not be regained via evolution. We’ll discuss how well Dollo’s Law has held up a bit more further down.