Perplexed in Peoria wrote:
> "Bob O'Hara"  wrote in
message news:cels02$176s$1{at}darwin.ediacara.org...
> 
>>Perplexed in Peoria wrote:
>>
>>>We computed absolute fitnesses using two methods.
>>>* Standard: Every cat born has an absolute fitness which is
>>>  the total number of child cats that are born to it.
>>>* "Edserian" Every cat that leaves the nest (ie. reaches
>>>  sexual maturity) has an absolute fitness which is the
>>>  total number of its children that leave the nest.
>>
> [snip]
> 
>>Actually, neither of these "fitnesses" are actually
fitness measures, as
>>they are only components of fitness.  They should properly be called
>>fitness components.  What if there was a large variation in over-winter
>>survival?
> 
> 
> I'm not sure I understand you.  Perhaps if you said what you think some
> of the other (missing) fitness components are ...
> Or perhaps I was not completely clear in stating that these are full-lifetime
> fitnesses for a single-year cohort of cats.
> 
But you measure this by counting either the number of offspring that 
leave the nest, or the number that become sexually mature (in the 
autumn).  So, even with Edserian fitness, you miss out over-winter 
survival (assuming you count sexual maturity as occuring in the autumn, 
which is what the evidence points to.  It's not clear from the text if 
this is what was actually done).  There might also be an effect on the 
chance of finding a mate (e.g. if a potential mate doesn't like the 
stains from the regurgitated food).

Basically, when calculating a total fitness, you always need to ensur 
you measure over a full life cycle.

> Also, I'm not sure what you mean by variation in over-winter survival.
> Are you referring to variation between winters, or to variation between
> types of cats?  If variation between winters, then I suppose that it
> would have been better to include multiple annual cohorts in the data.
> 
I meant variation between types of cats.

You'll also be please to know that my calculator has been sacked, and is 
now looking for a job at Enron.

Bob

-- 
Bob O'Hara

Dept. of Mathematics and Statistics
P.O. Box 68 (Gustaf H„llstr”min katu 2b)
FIN-00014 University of Helsinki
Finland

Telephone: +358-9-191 51479
Mobile: +358 50 599 0540
Fax:  +358-9-191 51400
WWW:  http://www.RNI.Helsinki.FI/~boh/
Journal of Negative Results - EEB: http://www.jnr-eeb.org
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