Posted on 12/05/2005 3:00:51 PM PST by dawn53
I get my boxer shorts at K-Mart in Cincinatti.
My bad: how can reproduction rates average anything other than one per individual with a stable population?
That was my answer.
Son thought it had to do with every 10 years, 120,000 are born so in a thousand years 12,000,000 births would give you a rate of 1.2.
Not really a for credit problem, they just turn in their homework, get credit that they've worked on it and then discuss it.
Right.
No, you can't just assume a birth rate, however plausible. The problem says one offspring per ten years. If there's 1 in a million per generation, then there are 100 generations in 1000 years, then you have 100 mutations per individual in 1000 years, or 2,400,000 mutations in the total gene pool. That's small compared to the mammalian genome, so two successive mutations at the same site can be neglected.
It's a sloppily designed problem though.
Sorry, meant 12, not 1.2.
And therein is the problem, some folks are getting what my son things the answer is and some are getting what I think the answer is.
The conflict continues, LOL.
Only the birthrate matters, because you're given the 24K fixed population. Supercat's answer is right in #20.
Let's just say the prof is not one of my son's favorite...he's taking the Bio class to finish out his general ed requirements (you have to have science in both disciplines and up until now, he had not taken any science classes on this side of the aisle.)
Heh.
Good luck!
If, as stated, each antellope averages five offspring over a ten year lifetime, the population of antellopes cannot possibly be stable at 24,000 (or any number). Rather, the population would increase fivefold every ten years, ten-million-fold per century, and by a factor of almost 10^70 over the course of a millenium.
There are three variables supplied: average birth rate per individual, average lifespan, and rate of population growth (which is specified as none). The supplied values for these variables are contradictory.
Hey this is the kid posting. Thanks for the help.
The first time I did the problem I got 12 as well but then I thought about it more, confused myself, then came back to that answer.
I figured that because there were 5 births every 10 years per individual, the population was replaced every 2 years. I then took the 24000 multiplied it by 500 (1000/2). Then divided by 1000000 to get the final answer.
Thanks again for the help.
Pops. generally cycle about some average num. depending on death and birthrate. The problem is simplified by using the average pop. size. In this problem birthrate = deathrate.
Oops, didn't see the comment about 5 offspring. Sorry.
If we get 0.5 offspring/year/antelope, and it takes two antelope to produce an offspring, then the birth rate is 0.25 offspring/year/antelope. The death rate then has to be 0.25/year; every antelope has a 25% chance of dying per year. I don't see that as a problem.
I agree.
There you go. Keep up the good work.
It's as good as any other answer, but supercat is right. You can't have 5 births per individual every 10 years, a life span of 10 years, and a stable population.
The birthrate is given as births/animal/decade. The deathrate is deaths/animal/decade.
birthrate = deathrate
What's contradictory?
Birth rate is stated as 5 per animal per decade. Death rate is one per animal per decade. Birthrate is not equal to death rate, even though a stable population would require it to be so.
This question cannot be answered as is:
What is the ratio of males to femals in the steady state population of 24,000?
Are we to assume that this discussion relates ONLY to females that equates to only 50% (12,000) of the poplulation or what?
Sheesh...stupid problems from even more stupid teachers.
G
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