Life History Traits

[jeskill]

My prof gave us this definition for life-history traits: "a set of rules used to allocate energy and time between reproduction and growth."

 

I think this is a bad definition. I didn't like the Wikipedia one either, although it's better: "key maturational and reproductive characteristics that define the life course."

 

What do you think? Is there a better definition or am I just being picky?

[wgargan]

You dont indicate what you think is wrong with it. I beleive the first one is sound for beginers. The wikepedia ( f-wikepedia please use a different source) definition just uses different words to say the same thing. Wikepedia uses "key" and "characteristics" instead of a "set of rules". i think they are fine.

[PhDP]

jeskill, I think the definition is ok. Life history can be resumed by;

 

[math]1 = \int_\alpha^\infty e^{-rx}l(x)m(x)dx[/math]

 

[math]\alpha[/math] is age at maturity, l(x) is the change to survive to age x, m(x) is the fecundity function (generally of the form fecundity = a[body size]^b) and r is the intrinsec rate of growth (a measure of fitness). Life history is about strategy, is it better to invest in survival, growth or fecundity ? As fecundity rise with growth, it's a good idea to invest in growth when mortality is low. But again, it can be shown what a genotype can have higher fitness even if it has lower survival AND fecundity, simply by having offsprings early in life (because they start spreading their genes faster, so the contribution of that genotype would be higher). It's a question of trade-offs, you can't have it all !

 

Life history evolution is, in my opinion, one of the most interesting aspect of evolutionary biology, simply because it's very close to the concept of fitness and it has proven its predictive power.

[Prime-Evil]

You might just be being picky. Whether you call them rules or traits is interesting. Rules sort of implies deliberate intent, but it can also imply mechanisms with an apparent or perceived intent or systematic functionality. Traits are OK also. Somewhat more objective. Perhaps a little too lifeless. I suppose it depends on whether you are more of a biologist or a chemist.

 

I am an engineer, so I am neither pretending to be both.

[jeskill]

You might just be being picky. Whether you call them rules or traits is interesting. Rules sort of implies deliberate intent' date=' but it can also imply mechanisms with an apparent or perceived intent or systematic functionality. Traits are OK also. Somewhat more objective. Perhaps a little too lifeless. I suppose it depends on whether you are more of a biologist or a chemist.

 

I am an engineer, so I am neither pretending to be both. [/quote']

 

Yes, It was the use of the word "rule" that set me off. The word "rules" conveys a completely different meaning than the word "traits", at least to me. She explained her reasoning in a later lecture (basically going over the equation that Phil provided) and it made a bit more sense.