New Zealand Tree Stuck In Evolutionary Time Warp

sciencehabit writes "A eucalyptus-like tree from New Zealand is still waging a battle that should have ended over 500 years ago. The tree continues to sport evolutionary adaptations, such as barbed leaves, to protect it from a large, flightless bird known as a moa. There's just one problem: the moa went extinct around 1500 AD."

Comments

Why would it lose them?

[srothroc]

If the leaves don't hurt the tree in its current environment, there's nothing that would keep trees with that particular trait from proliferating, even if the moa is no longer around to weed out the ones without the trait.

unless it's a disadvantage .....

[thephydes]

Unless it's a disadvantage for the tree to have barbs there is no "reason" for it to change. Evolution is about survival, it is not about changing because something you have is no longer used. I cite our toenails as examples.... do we need them? No. Are they disadvantageous to have for our survival? No. Hence we still have them, even though a significant number of our modern population can no longer see then over their fat guts.

Re:It is a common misconception about evolution

[sakdoctor]

Three words that destroy any possibility of intelligent design: Recurrent laryngeal nerve

The nerve is ridiculously circuitous in humans, but was a direct path when it first evolved in fish.

Misunderstanding evolution

[crmarvin42]

In evolutioary term, all costs are relative.

If, in the time that there have been no Moa to eat the plant, no genetic mutation has spontaniously developed that results in no thorns, then why would we expect these trees to have lost stopped growing thorns? Thorns are only expensive if some of your peers are not growing them and you are.

Since these thorns appear to be a defining characteristic of this plants phenotype, and there has only been a small amount of time in which to evolve away from this phenotype (evolutionary time scales are a lot larger than 500 years), it's stupid to assume that they would have dissapeared by now.

Evolution has no plan, it has no engineers deciding what the best design is now that the Moa are dead, it is the net effect of environmental selective pressures combined with the accumulation of small genetic point mutations over time that make one genetic line more likely to reproduce more prolifically, crossed with a whole lot of random chance.