Re: Could any paleobotanist tell me how long ago cordaites went extinct?

On Wed, 02 Nov 2005 04:50:04 -0800, Ron O wrote:

>
> George wrote:
>> "Ron O" <rokimoto@xxxxxxx> wrote in message
>> news:1130934317.636114.310390@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>> >
>> > Lin Liangtai wrote:
>> >> I wish to know exactly how many million years ago cordaites went
>> >> extinct on earth or in the North America. Experts' comments would be
>> >> much appreciated.
>> >
>> > Just do your own web search. You will find out that you are a cordate
>> > (I assume that you are a human, mammal, terestrial tetrapod,
>> > vertebrate, cordate). Are you extinct?
>> >
>> > Ron Okimoto
>>
>> Umm, that would be "cordaites", which is a paleozoic tree.
>
> I just thought that he misspelled it, and I was sort of joking around.
> We'll find out if he ever responds.
>
> Short answer is that you can't tell when something goes extinct from
> the fossil record. You can tell when the last fossil specimen
> discovered existed. Take bristle cone pines. They live in a habitat
> that is currently not undergoing deposition, so they will leave no
> fossils. They are not extinct and may last millions of more years, but
> if they went extinct tomorrow and some deposition had occurred and
> fossils existed, 20 million years from now, you could dig up 99.99999%
> of the earths crust and not find the fossils. Since deposition is not
> occurring and there are no current fossils being produced, you can dig
> up the entire earth and not know when they went extinct.

Yeah, but if you dug up the whole earth, where would you put the dirt?

-matthew


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