U.S. Greenhouse Gas Emissions. In the United States, greenhouse gas emissions caused by human activities increased by 7 percent from 1990 to 2014. Since 2005, however, total U.S. greenhouse gas emissions have decreased by 7 percent. Carbon dioxide accounts for most of the nationâs emissions and most of the increase since 1990. Electricity generation is the largest source of greenhouse gas emissions in the United States, followed by transportation.
The phylum Arthropoda (jointed foot) has the largest number of species. In fact, about 85 percent of known species are arthropods, and insects alone make up about 75 percent of known species. Other arthropods include the centipedes and millipedes; the arachnids (spiders, scorpions, ticks, mites); and the crustaceans (barnacles, crabs, crayfish, lobsters, shrimp, water fleas). Obviously,
Phylum Arthropoda. This is the most extensive phylum in the animal kingdom. It is composed of 3/4 of all known species. Approximately 900,000 species of arthropods have been recorded. Included are spiders, scorpions, ticks, mites crustaceans, millipedes, centipedes, insects, and some others.There is an extended fossil record.Arthropods are eucoelomate protostomes with well-developed organ systems.Most species have combined or fused somites and appendages into functional groups called tagmata for specialized purposes. Although all types-carnivorous, omnivorous, and symbiotic-occur, the majority are herbivorous.In diversity of ecological distribution, the arthropods have no rivals.pproximately 900,000 species of arthropods have been recorded. Included are spiders, scorpions, ticks, mites crustaceans, millipedes, centipedes, insects, and some others. There is an extended fossil record. Arthropods are eucoelomate protostomes with well-developed organ systems.