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The flower

This is the ‘Bird of Paradise’ flower. The scientific name is Strelitzia reginae.   It shows virtually every color of the rainbow. Birds are attracted and land on the ‘beak’.  They push their own beaks into the flower to get some nectar, but as they do this they dislodge some pollen, or brush some pollen from somewhere else onto this flower.  The colors and design all benefit the plant by helping it to produce more seeds, and make new plants.

What colors say

Colors have so much to say. Find
here those that attract, others
that warn, those that say
“Can I be your friend?”,  
“Leave me alone!”, “I bet
you can’t see me”, or “I am
a great guy!”.

You will find pages in this book that not only show examples of colors in living creatures, but also deal with some of the benefits that colors may give.  The bright colors of the Bird of Paradise make the flowers visible to passing birds. It is like an invitation to visit  and have some food.  As you go through the pages, you find many more suggestions as to why organisms have colors.   But be cautious with the question ‘Why?’. Evolution relies on a process without purpose. Some evolutionary developments may not benefit organisms in any way.  Where possible, try to replace the “Why?’ question with ‘What benefits might that color bring?’

Pigments

Almost everything in
nature is  colored.
Most
colors come from special
chemical compounds
(pigments).  Look for
those with other ways to
be colored. And, who
makes their own light?
 

The word ‘pigment’ is a useful term. Pigments are strongly colored chemicals that are made by organisms. Use the word to explain  how colors are created.   They give color to a flower, or feather, or other part.  Not all colors come from pigments (a rainbow does not use pigments). The page on Iridescence points to some colors that do not come from pigment.  Most blues in animals do not come from pigment, but are caused by structures inside  cells and tissues. Finally a reminder that some organisms MAKE light – see the page on ‘Luminescence‘. 

Some colors, like the green of
plants, have a job to do.
They capture energy
that is in sunlight.
Others, like the
brown in our skin,
protect us
from what is
harmful in
sunlight.

The green of plants or our own tans are useful colors.  The green comes from pigments that capture the sun’s energy, harnessing it so that it can be used to make molecules, cells and tissues.  The melanin that tans our skin helps to block the penetration of ultraviolet light. That is good because ultraviolet (UV) light can damage how cells develop, and may cause cancer.   

Often we ask ‘Why’ that organism has that color.  Often, we do not know, and can only try to list the likely benefits   

Convergence in evolution occurs  when different types of organisms develop the same characteristics to do the same task.  Wings are a good example.  Birds, bats, bees, even some fish have developed wings so they can fly.  It is pretty clear that the primary benefit of having wings is to be able to fly.  We will see convergence with colors (many animals are brown, or different dangerous organisms use the same combinations of colors).   You can look for examples, and they may provide clues as to the benefits of those colors and patterns.

A step back

Not everything sees colors as we do.
Some may see more colors,
or fewer, or only one.
They may see what we think are
different colors as just the same.
What we think are the same,
some may see as different.

Remember,  we see the world one way. Most of us can distinguish over a million colors, hues, and shades.  We do so within  a limited spectrum of colors – the range being suggested by the ‘Red, Orange, Yellow,  Green, Blue, Indigo, Violet’ of rainbows.  We achieve that with 4 different receptors in your eyes (one for brightness, and one type each for blue, green and red light), and with a lot of help from our brain.  Other animals may see more colors than we do, or fewer, or maybe only brightness.  Most other vertebrates have 5 types of receptors.

Our eye is like a camera, with a lens that lets light in, focussed by the lens and cornea so that an image hits the back of the eye where the receptors are located. Insects have eyes designed like bundles of telescopes.  Some of the larger molluscs have eyes without some of the design faults that we have.  Some organisms see the ultraviolet that we do not. We have one view of the world, and there will be others. Indeed, we may not see something that has been a major influence on how organisms have evolved. 

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Nature Reader colors web Intro

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