Higgs Boson wrote:
Have often wondered how plants with dark foliage, like the dark red
canna, handle chlorophyll.

Wikipedia has a long article; this is the first graph:

Chlorophyll (also chlorophyl) is a green pigment found in
cyanobacteria and the chloroplasts of algae and plants.[1] Its name
is derived from the Greek words χλωρός, chloros ("green") and φύλλον,
phyllon ("leaf").[2] Chlorophyll is an extremely important
biomolecule, critical in photosynthesis, which allows plants to
absorb energy from light. Chlorophyll absorbs light most strongly in
the blue portion of the electromagnetic spectrum, followed by the red
portion. However, it is a poor absorber of green and near-green
portions of the spectrum, hence the green color of
chlorophyll-containing tissues.[3] Chlorophyll was first isolated by
Joseph Bienaimé Caventou and Pierre Joseph Pelletier in 1817.[4]

Read the whole thing if interested, and make any
comments...appreciated.

HB

The third section on why chlorophyll is green not black is quite interesting
to me. The explanation given, which I think is widely accepted in the
botanical community, is that some (apparently superior) structures and
functions of living organisms have not been reached by evolution because
there was no evolutionary pathway from where they came from to get there.
This accounts for the less than optimal structure of many aspects of life,
eg the human eye and the giraffe's neck. In fact it is characteristic of a
process that proceeds by many small connected steps to have such inferior
outcomes. A process of design (such as human engineering) can abandon a bad
design and take a completely different approach. Evolution cannot do that.
Evolution is undirected and has no 'final' target nor does it look to the
future as an engineer does, it can only work incrementally on choosing which
variation of structure or function is better suited to the environment the
organism is in at that time.

In case anybody thinks that evolution is too academic or even off topic, I
think it is fair to say that having an understanding of evolution of plants
and organisms that relate to plants (eg predators and symbiots) will make
you a better gardener.

David