Re: [dinosaur] Question

[Dann Pigdon <dannj@alphalink.com.au>]

On Wed, Mar 29th, 2017 at 2:54 PM, "Williams, Brandon R (West Kentucky 
Student)" 
<bwilliams0401@kctcs.edu> wrote:

> Hello, All, I have a question that I need help with. If anyone would answer
> it I would appreciate it. What is a predator: prey biomass ratio? How were
> these used in assessing dinosaur metabolism?

A predator:prey biomass ratio compares the number of predators to the number of 
prey in an 
ecosystem (or more correctly, compares their mass rather than their numbers). 
If you can measure 
this ratio accurately (and it's unlikely that you can for long-extinct 
ecosystems), then you can make 
assumptions about the metabolism of that ecosystem's predators.

If an ecosystem is to remain sustainable, its predators must not kill prey 
faster than their prey can 
reproduce, or their prey will become extinct and the predators will run out of 
food for themselves. 
Endothermic ("warm-blooded") predators need a lot more food to survive than 
exothermic ("cold-
blooded") predators. An ecosystem with a lot of warm-blooded predators must 
have fewer predators 
relative to their prey numbers than an ecosystem dominated by cold-blooded 
predators.

For instance, a warm-blooded mammal such as a leopard might have to kill two 
antelopes a week to 
keep itself fed, whereas cold-blooded reptiles such as komodo dragons or large 
pythons (predators 
with similar masses to leopards) might only have to eat one large meal a month. 
That means the 
leopard is eating about eight times as much food. An ecosystem where pythons or 
komodo dragons 
are the dominant predators could have eight times more predators than an 
ecosystem where leopards 
are the dominant predator, and that ecosystem could still remain sustainable in 
the long term.

-- 
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 Dann Pigdon
 GIS Officer
 Melbourne, Australia
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