visual range of animals: how some creatures exploit the spectrum
In this essay, I will
be exploring the different types of vision in ecology and explaining the
optical mechanisms which give some animals the ability to see a world that humans cannot. I will
begin this essay with a brief explanation of colour vision in humans which will
explain many of the foundations of the visual mechanisms which will be
discussed in this essay. I will then continue by exploring some of nature’s most
extraordinary eyes and the mechanisms behind them.
Colour vision in the Human eye
The Human eye consists two types of light sensitive cells, called rods and cones,
with the cone cells being responsible for the colour vision. Humans are said to
be trichromatic as the human eye has 3 types of cone cell; Short wavelength
(S), Medium wavelength (M), and Long wavelength (L). S, M and L cone cells have maximal absorption (?max) peaks at 445, 525 and 555-570 nm respectively due to
the differences in their photopigments 1. Thiis is the basis of Young- HelmHoltz
theory of colour vision .