Light
What is light?
Sunlight is a portion of the electromagnetic radiation given off by the sun, particularly infared, visible, and ultraviolet light. Light that is visible to the human eye has wavelengths from 400 -700 nm on the electromagnetic spectrum.
How does light vary?
Light can vary in both intensity (the amount of energy transmitted, measured in lux) and quality (spectral composition, measured in nm). Both light intensity and quality can vary with time (daily, seasonally) and with location.
How do animals sense light?
Animals sense light with a wide variety of photoreceptors, or light-sensing organs. These photoreceptors all share the common characteristic of light-sensitive pigments, which absorb light energy and are the first step in initiating light-inducing, or photic reactions. The sensation of light perceived by these receptors can range from simply perceiving light intensity or direction, to forming high-resolution and colour images.
How do animals respond to variation in light intensity?
Negative Phototaxis: moving away from the light
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Positive Phototaxis: moving towards the light
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To learn more:
Freeman S, Harrington M, Sharp J. 2014. Biological science. 2nd Canadian ed. Toronto: Pearson.
Smith TM, Smith RL, Waters I. 2014. Elements of ecology. Canadian ed. Toronto: Pearson.
Note: Any edition of the above books or other biology and/or ecology textbooks could be useful.
Freeman S, Harrington M, Sharp J. 2014. Biological science. 2nd Canadian ed. Toronto: Pearson.
Smith TM, Smith RL, Waters I. 2014. Elements of ecology. Canadian ed. Toronto: Pearson.
Note: Any edition of the above books or other biology and/or ecology textbooks could be useful.