Interesting story. But hasn't the Sun been getting hotter, which would
mean moving from yellow toward green rather than the other way. And
it's still still more a yellow than green store. So why don't the
red/blue pigmented plants out compete the green ones. I think there
must be more to it. Is the chlorophyll pathway more efficient?
Brent
On 6/6/2018 4:00 PM, Russell Standish wrote:
On Wed, Jun 06, 2018 at 03:16:31PM -0700, Brent Meeker wrote:
On 6/6/2018 8:19 AM, Telmo Menezes wrote:
But in the early days of life on this planet random
mutation and natural selection stumbled upon a key molecule in the
photosynthesis process, chlorophyll, that just happens to be green and it
works OK, not perfectly but OK. In Evolution you don't have to be perfect
you just have to be better than the competition. And once Evolution started
to go down the chlorophyll path it soon became committed and it became
virtually impossible to backtrack and look for something better than
chlorophyll.
Ok, so didn't you just explain why plants are green?
Is "It happened at random." an explanation?
FWIW, the photosynthesis story is much more interesting. The first
photosynthetic organisms absorbed light right at the peak of the Sun's
spectrum (being a yellow star, that's right in the yellow-green
band). As a consequence, these organisms reflected the red and blue
parts of the spectrum, appearing a purplish colour. Their modern day
descendents go by the name "red-blue algae", and tend to have rather
poisonous consequences on modern eukaryotic life when they get out of
control.
Then one day, an organism discovered a different photosynthetic path
based on chlorophyl. Because the oceans were covered in this purplish
stuff absorbing all the green light, all that remained was the red and
blue ends of the spectrum. Hence chlorophyl got optimised to absorb
those frequencies, reflecting back the remainder, which is green.
That is why modern plants are green, which is not an optimal colour nowadays.
BTW - red-blue algae find oxygen poisonous, it was photosynthetic
plants that killed off most of the red-blue algae, setting the scene
for animals to arise, which depend on their oxygen waste gas.
Cheers
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