What limits a species life?

[wrsni]

I suppose you might as well ask why humans generally live for 70 or 80 years while dogs are in the low teens.

 

There'll be a scientific explanation somewhere but I try not to waste too much thought on things that can't be changed.

[woodyguy]

I think what is really interesting is why coppicing seems to make many fairly short lived trees almost immortal. Its the same genetic repair mechanism in both normal grown and coppiced but the result is very different.

[Bren.]

I know, takes more than my feeble mind to work it out.

Someone, somewhere will know though.

[Darkslider]

The subject of immortal trees is an interesting one, think I read somewhere that some of the oldest trees in existence today were seeded not long after the last glacial ice age finished, some 10k years ago. I wonder if they were looked after and protected from disease and outside influences if they'd carry on until the next ice age?

[Gary Prentice]

I think what is really interesting is why coppicing seems to make many fairly short lived trees almost immortal. Its the same genetic repair mechanism in both normal grown and coppiced but the result is very different.

 

Its something to do with the age of the reproductive cells (meristems),young wood is the same in coppice as pollards. I don't know if energy usage is also involved but growth is directed more primarily than secondary (thickening)

[woodyguy]

But in mammals, each time the DNA is copied they lose a telomere (think of a deli counter ticket, at the end of one chromosome). Once they've gone you're old and decrepit = death. So cells can only be copied a certain number of times. Interesting that bristle cone pines are the longest lived yet grow the slowest. Coppiced trees grow pretty fast but are also long lived. This however is very different from the survival strategies of short vs long lived trees, growing to maturity.

[AA Teccie (Paul)]

Sadly there is no such thing as the greater good. Just what has worked on an evolutionary basis for that particular species of tree. So Birch need light and will establish very quickly and grow very fast. Like most such organisms, they die young but produce prolific seed at low cost (cf acorn) so are quickly replaced but in a different place.

An oak takes most of a birch lifecycle to get big enough to fruit. Its seed are expensive and not produced every year. But by being long lived they only need to be successful once every few hundred years for the species to spread.

So different survival strategy between the two species.

 

I said the 'wise®' ones would be along soon.

 

Good stuff, thank you ...and of course that's what I meant to say

 

Merry Christmas..

Paul

[easy-lift guy]

I thought that the words Natural and selection weren't to be used together over your side of the pond. Nice to see some of you do.

 

How about Natural selection through evolution and Mother nature filling in the blanks.

easy-lift guy

[Bren.]

How about Natural selection through evolution and Mother nature filling in the blanks.

easy-lift guy

Think there might be some states where they can legally hang you for saying that. There still seem to be a lot of people over there who think the Judge in the Scopes Monkeys Trial was Satan himself (and a lot of schools ignoring the law, seemingly with impunity). Mind you we're starting to see it over here too.

[Bren.]

But in mammals, each time the DNA is copied they lose a telomere (think of a deli counter ticket, at the end of one chromosome). Once they've gone you're old and decrepit = death. So cells can only be copied a certain number of times. Interesting that bristle cone pines are the longest lived yet grow the slowest. Coppiced trees grow pretty fast but are also long lived. This however is very different from the survival strategies of short vs long lived trees, growing to maturity.

You sir, have missed your calling in life, best non-technical description of a telomere, I've ever read. You should have been a teacher.