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An evolutionist suggests that at some distant point 400 million years in the past one of his ancestors was an early form of fish. Try to estimate the number of generations that link the scientist to the fish. To make your estimation, you will need to fill in sensible values for the species in the table below (you will possibly need to research these numbers, and feel free to use a spreadsheet for the calculations. A good place to start is http://en.wikipedia.org/wiki/Timeline_of_human_evolution)

    Category
    First appearance (million years ago)
    Similar modern day example
    Similar modern day creature Time from birth to producing first offspring Lifespan (years)
    Bony fishes 400 Coelacanth
     
     
    Amphibians
    350
    Lungfish
     
     
    Reptiles
    300
    Lizards
     
     
    Early mammals
    200
    Small dogs
     
     
    Mammals
    75
    Lemurs
     
     
    Apes 15 Gorillas
     
     
    Humans
    1
    Charles Darwin 30 73

    Can you produce a sensible estimate for a number that you are confident exceeds the actual number of generations?

    Can you produce a sensible estimate for a number that you are confident is definitely less than the actual number of generations?

    There will be various estimates and assumptions that you need to make in this question. Can you clearly state the most important factors?

     

     

     


    NOTES AND BACKGROUND

    Suggested timelines for evolution form fascinating reading.

    Interestingly, the bony coelacanth fish was considered extinct by scientists until fishermen caught one alive in 1938. Now they occasionally turn up, caught in deep-water nets.