This 7 page research paper describes the arrival of zebra mussels on the North American continent as well as some projected figures for their spread. The writer describes the biology of these small, inedible shell fish and then explains some of the negative effects they can have on aquatic systems. Since phytoplankton and detritus consumed by tiny animals called zooplankton which in turn are eaten by small fish and these small fish by larger fish, biologists seem concerned that zebra mussels' tendency to eat the same items could damage established food chains by removing needed energy from its bottom level. Bibliography lists 8 sources. A 7 page paper outlining the evolution of the lung from the primitive lungfishes to mankind.
Bibliography lists six sources.
A 7 page outline of the characteristics mammals have in common with their predecessors the reptiles and the features which distinguish them. Bibliography lists five sources. A 5 page overview of the evolution of plants and animals. Compares and contrasts the evolutionary paths of the first plant and the first animal and traces those paths back to the primordial soup from which that very first organism emerged. Discusses differences in anaerobic and aerobic organisms and details the evolution of mitochondria and chloroplasts.