Zachriel
Posts: 2723
Joined: Sep. 2006
|
| Quote (midwifetoad @ July 02 2009,10:11) | Forgive me for having trouble with the meltdown concept. Is there an observed instance in the real world of a reproducing population going extinct due to the accumulation of deleterious mutations?
What would that look like? |
In asexual populations, it's rather easy to understand. If most offspring are mutants, they are nearly always of lower fitness. Organisms such as bacteria have low individual mutation rates, and most offspring are exact clones. Even then, they often recombine genetic material.
It's a bit different in sexually reproducing species such as vertebrates. Bottleneck populations, species that have had their habitat severely reduced, or varieties near range edges, are believed to suffer mutational meltdown. Reproductive rates and numbers of viable offspring tend to decline due to inbreeding, and that can make the species vulnerable to extinction. It's a problem with many species being pushed to the brink by humans.
Hybridization can sometimes reinvigorate a species.
--------------
You never step on the same tard twice—for it's not the same tard and you're not the same person.
|
