BIO120H1 Chapter 3: Bio Chapter 3.doc
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BIO120H1 Full Course Notes
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Chapter 3 adaptations to the physical environment: light, energy and heat (38-45, a; 46-47, c; 48-58, a) Green plants will primarily absorb light of wavelengths of 400 nm (violet) and 700 nm (red), belonging to the photosynthetically active region of the spectrum. Irradiance: intensity of light of all wavelengths hitting a surface. Albedo: proportion of light reflected by a surface (albedo of water < plants < ground, soil). Chlorophyll is a plant"s primary pigment, it absorbs red and violet light and reflects blue and green (thus most plants are primarily green in colour). Plants also have accessory pigments, namely: xanthophylls and carotene, which absorb and reflect different wavelengths. Most deep-sea algae can absorb green light and reflect red and violet, this is because water is more likely to absorb longer wavelengths (like red), especially with increasing depth. The first stage of photosynthesis is the collection of light. This is accomplished by a plant"s photosystem (consisting of chlorophyll and accessory pigments. )
