发信人: Marble (小石头哥哥), 信区: Biology
标 题: Re: 急问各位大虾一个生态学问题.
发信站: The unknown SPACE (Mon Apr 15 15:11:41 2002), 站内信件

i think so. for logistic population growth, the equation is
N(t)=K/(1+Ce^(-rt)). and C=(K-N(0))/N(0), r is the intrinsic
rate of increase in population number, K is the carrying
capacity of the environment. so taking them together, you have
to think about the available resources provided from the
environment, the intrinsic growth rate of the species and
possible mutations(?). so maybe draw a plot will help you
decide that whether the species have already got to its population
peak or at the plateau. but my understanding is that unless you
have observed dramatic change in population size, you cannot
predict that the species is in decline. for the later, i think
the simplest model is exponentially decline, while N(t)=rN(t-1),
where 0<r<1. given the criteria of extinction, you can calculate
how many generations it takes for current generation to drop
to extinction. you should check some reference.

【 在 springerz (烟囱) 的大作中提到: 】
: logistic equation?
: 【 在 lossmiss (hehe) 的大作中提到: 】
: : How to determine that a species is in decline?
: : How might you estimate extinction time?
: : Thanks!


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