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Unformatted text preview: Bio 124 Evolution and Organismal Diversity Winter 2012 Group Member Names: ___________________________ ___________________________ ___________________________ ___________________________ Grade: ______/20 points Week 7 Lab Plant Diversity A. Photosynthetic Pigment Nutritionally, two basic types of organisms exist in our world, autotrophs and heterotrophs. Autotrophs are organisms that are capable of synthesizing their own food. They are further divided into phototrophs and lithotrophs depending on how they make their own food. Phototrophs utilize the light as an energy source while lithotrophs rely on inorganic compounds as electron donors for energy production. The majority of phototrophs are plants while lithotrophs are mainly bacteria. Heterotrophs are organisms that rely directly or indirectly on autotrophs for their nutritional carbon and metabolic energy. Heterotrophs include animals, fungi, many protists and most bacteria. Photosynthesis is the process utilized by photoautotrophs by which light energy converts inorganic compounds into organic substances with the subsequent release of elemental oxygen. Without photosynthesis, most living things would starve, and atmospheric oxygen would become depleted to a level incapable of supporting animal life. The photosynthetic reaction is often summarized by the equation: (Light) 12H 2 O + 6CO 2 6O 2 + C 6 H 12 O 6 + 6H 2 O Although glucose (C 6 H 12 O 6 ) is often produced during photosynthesis, it is usually converted to another transport or storage compound such as starch. Iodine solution is used to identify starch and can therefore be used to determine where photosynthesis is occurring. In this portion of the lab you will conduct an experiment to determine what areas of the Coleus leaf are photosynthetic. Before beginning the experiment, examine your Coleus leaf and hypothesize about the location of photosynthesis based on leaf coloration....
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