Article in the NYTimes
(Image from Wikimedia by Mila Zinkova)
8/21/10
A nice example of convergent evolution? Not so fast....
Puffer fish toxins probably come from their diet, and remarkably, pufferfish have gene mutations that make them resistant to the effects of the toxins. Furthermore, other species, like snakes, have evolved resistance to these toxins!
Article in the NYTimes
(Image from Wikimedia by Mila Zinkova)
Article in the NYTimes
(Image from Wikimedia by Mila Zinkova)
Why do female great apes (including humans) and female whales go through menopause?
It's about trading off between having new offspring, and investing in current offspring. I'd hazard a guess that it's more likely to evolve in cooperatively breeding groups with long lifespans....
Article on BBC
Read more about the "Grandmother Hypothesis"
Article on BBC
Read more about the "Grandmother Hypothesis"
Evidence of Sexually Selected Traits in Prehistoric Animals
Apparently many of the elaborate and bizarre traits found on "dinosaurs" were a result of either male-male competition or female choice!
Article on BBC
Article on BBC
8/18/10
Essay collection from Colorado State University
I was looking up references on eusocial aphids for a paper I'm working on, and found this nicely written review article by Tim Judd. Always a sucker for working my way up complex URL's, I found that there is a large collection of student essays on all sorts of interesting entomological topics. Check it out!
(p.s. I think the prof is Louis Bjostad)
For example:
For example:
Sexy-time with myself... scared snails do it alone!
Josh Auld (2010) found that scared snails (exposed to signals from predators) will reproduce by themselves rather than wait to find a partner to exchange eggs and sperm with.
Abstract:
Environmental effects on mating system expression are central to understanding mating system evolution in nature. Here, I report the results from a quantitative-genetic experiment aimed at understanding the role of predation risk in the expression and evolution of life-history and mating-system traits in a hermaphroditic freshwater snail (Physa acuta). I reared 30 full-sib families in four environments that factorially contrast predation risk and mate availability and measured age/size at first reproduction, growth rate, a morphological defense, and the early survival of outcrossed/selfed eggs that were laid under predator/no-predator conditions. I evaluated the genetic basis of trade-offs among traits and the stability of the G matrix across environments. Mating reduced growth while predation risk increased growth, but the effects of mating were weaker for predator-induced snails and the effects of predation risk were weaker for snails without mates. Predation risk reduced the amount of time that individuals waited before self-fertilizing and reduced inbreeding depression in the offspring. There was a positive among-family relationship between the amount of time that individuals delayed selfing under predation risk and the magnitude of inbreeding depression. These results highlight several potential roles of enemies in mating-system expression and evolution.
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