Living things that can make their own food—autotrophs—are the basis for all food webs. On land the most important autotrophs are plants; in the ocean, the major autotrophs are phytoplankton: microscopic algae, bacteria, and protists that use chlorophyll and other light-harvesting pigments to capture sunlight for photosynthesis. When phytoplankton populations get large enough, their pigments color the surface waters of oceans, seas, and lakes with shades of brown, green, or turquoise.
Effect of different colors of light on the rate of photosynthesisThe effect of different lights on plant growth: incandescent light, fluorescent light, sunlight and black light.
Follow in the steps of van Helmont, John Woodward, Joseph Priestley and Jan Ingenhousz and discover photosynthesisIs plant growth affected by exposure to ultraviolet light?
The Effects of pH Levels and Phosphorous on the Photosynthesis Process of Aquatic PlantsStudy the coniferous spruce tree (Picea glauca as the species of choice) by measuring its lateral and sub-lateral branch angles in order to see how it collects sunlight from various angles on its south-facing side.
Chlorophylla-a is the primary for in plants. Its structure is shown at left. It has the composition C55H72O5N4Mg. It exhibits a grass-green visual color and absorption peaks at 430nm and 662nm. It occurs in all photosynthetic organisms except photosynthetic bacteria.
Applying ultra-violet visible spectrophotometry and various types of chromatography to compare the amounts of certain photosynthetic pigments in fresh, frozen, and canned phaseolus vulgaris and spinacia olercea.
Some plants and plantlike organisms have developed other pigments to compensate for low light or poor use of light. Cyanobacteria and red algae have phycocyanin and allophycocyanin as accessory pigments to absorbe orange light. They also have a red pigment called phycoerythrin that absorbs green light and extends the range of photosynthesis. The red pigment is found in vegetables. Some red algae are in fact nearly black, so that increases their photosynthetic efficiency. Brown algae have the pigment fucoxanthin in addition to chlorophyll to widen their absorption range. These red and brown algae grow to depths around 270 meters where the light is less than 1% of surface light.
in plants is dependent upon capturing light energy in the pigment , and in particular chlorophyll a. This chlorophyll resides mostly in the and gives leaves their green color. The range of light absorption in leaves is extended by some such as the , but does not cover the entire visible range - that would make the leaves black!
An ecosystem consists of the whole community of living organisms (biocenosis), the abioticcomponent of a certain environment (biotope) and their relationships.
The relationships essentially consist in a flux of substances which pass from thenon-living components to living ones and in a flux of energy which passes from thephotosynthetic organisms (plants) to the herbivorous animals, then to carnivores. Thewastes and the dead organisms are then decomposed by the micro-organisms which brake downthe substances back to simple components, in a full cycle.
1 - With a shovel in a field or in a wood, dig a square hole of about half a meter (1 1/2feet) square and about 40 cm (18") deep. Describe the non-living components of thesoil and all forms of life you find: roots, earthworms, snails, centipedes, spiders,crickets, etc. To complete the description of the ecosystem of the soil, look forinformation on the role of each of these organisms and the relationships with the otherforms of life of this environment.
2 - In similar way you have studied the soil ecosystem, you can analyze other ecosystemssuch as the ones in a forest, pond, shore, or desert.
G. and L. Durrell (2) can be useful, or there are many other books on this matter.
An Illustration of a Soil Ecosystem
Protocols for a Soil Ecosystem Approach for Characterizing Soil Biodiversity
Internet keywords: soil ecosystem.