Life on Earth is divided among three domains, or large groupings. Two of these, Archaea and Bacteria, are comprised exclusively of microbes. The third group, Eukaryota, contains both multicellular and microbial life, according to the University of California Museum of Paleontology. This classification system developed in response to a dawning awareness that much of life's diversity is confined to microbes.Continue Reading
Bacteria are among the oldest living things on Earth. Fittingly, this group is also one of the most genetically and morphologically diverse. Some bacteria are destructive to plants and animals, while others live in symbiosis with them. Others are important commercially or as the base of the food chain, as reported by UCMP.
Archaea are some of the hardiest organisms on Earth. This domain is home to the so-called extremophiles that make their living in the superheated water of hot springs as well as hypersaline lakes and deep-sea seeps. Archaea are also abundant among the ocean's plankton. According to UCMP, Archaeans' affinity for extreme environments makes them difficult to culture in the lab.
The third major classification for life is Eukaryota. Eukaryotes are the group that includes all animals, plants and fungi. The group also includes microbes known as protists. This group includes the amoebae and radiolaria.Learn more about Zoology
The slowest living creature on Earth is the sloth, which is an herbivorous mammal that is primarily found in South and Central American rain forests. Sloths are especially slow on land because they have weak hind legs that provide little strength and because they have large claws that also hamper their ability to move.Full Answer >
The qualities of a good index fossil are that it belongs to a relatively abundant and widely dispersed species that nevertheless existed for only a brief time on Earth. Marine animals best suit these parameters as sea currents carry them to distant shores where the tide gradually layers upon them the sediments that later form solid, sedimentary rock. The most common index fossils are the pre-historic mollusks called ammonites.Full Answer >
No animal on Earth has four knees, only two. All animal skeletons consist of essentially the same bones and joints, just expressed in different shapes or forms.Full Answer >
Animals are an integral part of the Earth's ecosystem. Each organism in the ecosystem plays a role in supporting the ecological community, which means that animals play a vital role as well. Each organism in the ecosystem depends on the other organisms in the system to play its role. Without animals, there would be dysfunction within the system and human life would be disrupted.Full Answer >