Structural Coloration In Animals

INTRODUCTION

Pigments are chemical compounds, which reflect only certain wavelengths of light. Plants also have the ability to absorb certain wavelengths.

There are three main types of pigments; chlorophyll, carotenoids, phycobilins.

Chlorophyll: This is a green pigment found in cyanobacteria, algae and plants. They are greenish pigments, which contain a porphyrin ring. A porphyrin ring is a stable ring-shaped molecule around which electrons are free to migrate. So, because the electrons move freely, the ring has the potential to gain or lose electrons easily, and thus the potential to provide energized electrons to other molecules. This is the fundamental process by which chlorophyll captures the energy of sunlight.

There are several kinds

Colours are produced when a material is scored with fine parallel lines, formed of one or more parallel thin layers, or otherwise composed of microstructures on the scale of the colour's wavelength.

Structural coloration is responsible for the blues and greens of the feathers of many birds (the bee-eater, kingfisher and roller, for example), as well as many butterfly wings and beetle wing-cases (elytra). These are often iridescent, as in peacock feathers and nacreous shells such as of pearl oysters and Nautilus. This is because the reflected colour depends on the viewing angle, which in turn governs the apparent spacing of the apparent spacing of the structures responsible. Structural colours can be combined with pigment colours: peacock feathers are pigmented brown with melanin.

Both plants and animals are eukaryotes; they have had separate ways of evolution for more than a billion years. Their last common ancestor was a unicellular eukaryote that had mitochondria but no chloroplasts. The plant ancestral line acquired chloroplasts after plants and animals separated. The earliest documentation of fossils for multicellular plats and animals date to over six hundred years ago. Hence, it seems that plants and animals evolved their multicellular features at different times from each other, each starting from a different unicellular eukaryote, sometime between one point six and six billion years

In much the same way a plant grown in darkness grows long and tall as it tries to find light, the same type of plant will grow differently outside when exposed to light. They are both genetically identical but the genes that control growth are switched on or off in response to light.

This shows that this may be the reason why plants get their colour and not because of the pigment or it maybe a combination of the two. This question can only be answered with further experiment and evaluation. This experiment was not reliable because it was conducted in school. More repeats should be conducted to get a fairer and more reliable test. The equipment had uncertainties; the measuring cylinder had and uncertainty of ±0.01cm, this could be improved by using a measuring cylinder with a lower uncertainty.

Also since not all of light energy is used for photosynthesis this may not be a reliable