These Are a Diverse Group of Organisms Living Almost Everywhere. Many Species Are Beneficial

While organisms in this kingdom have genetic material, it is not enclosed or surrounded by a nuclear envelope. Therefore, these organisms ‘technically’ do not have a nucleus. Their genetic material is in the form of a single circular chromosome. All members of this kingdom are single- celled or unicellular. Some are producers and can “make their own food” through photosynthesis or chemosynthesis. Technically, they can convert inorganic compounds, such as carbon dioxide and water, into organic compounds, such as glucose. In the process they give off oxygen as a byproduct. While these organisms are autotrophic, many are heterotrophic. Depending on the species, oxygen may be toxic, tolerated, or needed for their metabolism. Except for one, all organisms in this kingdom have a cell wall supporting their cell membrane. They reproduce asexually by splitting in half which is called binary fission. They can exchange genetic information through conjugation.

These are a diverse group of organisms living almost everywhere. Many species are beneficial such as those that convert nitrogen into a useable form for plants. Others, such as E. coli, aid with digestion. While many are helpful, others are pathogenic causing diseases such as cholera, strep throat, and tuberculosis. Antibiotics have been developed to help attack infections caused by these organisms.

1 They are called the “ancient ones”. These unicellular prokaryotes are found in extremely harsh, even hostile, environments. Here they have carved out a niche for themselves where other organisms fail to thrive. Their cells are supported by cell walls. Many are autotrophic (but by chemosynthesis not necessarily by photosynthesis). Depending on the species, oxygen, hydrogen, carbon dioxide, or sulfides may be needed for their metabolism. They reproduce asexually by binary fission. They have been found living in the hot springs and geysers of Yellowstone National Park as well as in the hot thermal vents of the deep ocean. Others thrive in highly acidic or salty environments such as the Dead Sea or the Great Salt Lake. Native to Yellowstone National Park, the Taq bacterium can survive in very hot environments and this property enables it to be used in genetic engineering to copy large quantities of DNA commercially.

2 These multicellular organisms have specialized cells that that form tissues. Their cells are complex and have nuclei with genetic material within. No members of this kingdom have a cell wall. Trading the extra rigid supportive boundary of a cell wall for flexibility and motility, these organisms can move from place to place. Most organisms in this kingdom reproduce sexually while a few have retained the ability to reproduce asexually. Being heterotrophic, all members are consumers and are dependent on ingestion of nutrients for energy. Oxygen is needed for metabolism. Mammals, birds, reptiles, fish, amphibians, as well as invertebrates belong to this kingdom.

3 These multicellular organisms have complex specialized cells that form tissues. Their genetic material, which is encoded in chromosomes, lies in the nuclei of their cells. All members are autotrophic or producers by photosynthesis where they convert radiant or solar energy into chemical energy that is stored in the bonds of glucose. Oxygen is needed for metabolism. The cells of these organisms have cell walls that give them extra support. They can reproduce sexually and asexually. Mosses, ferns, conifers, and flowering plants belong to this kingdom.

All members of this kingdom are multicellular (except one) and used to be classified as plants. However, they are classified into a kingdom of their own because their cells lack chloroplasts making it impossible for them to photosynthesize. Oxygen is needed for their metabolism. Nuclei can be observed in their cells as well as many other organelles. These organisms get their nutrients and energy by decomposing decaying matter. These organisms reproduce sexually and asexually. Cell walls give an extra boundary to their cells; however, they are different in composition than the cellulose cell walls found in plants. Mushrooms, mold, yeast, and mildews are all examples of organisms that belong to this kingdom.

5 Most organisms that belong to this kingdom are unicellular. Those that are multicellular do not form true tissues. Their cells are quite complex and have nuclei where genetic material can be found. Many are aquatic. Some of these organisms lack a cell wall and therefore are able to move actively. Others have a cell wall. Some are autotrophic and others are heterotrophic. Oxygen is needed for metabolism. Most reproduction is asexual though they can reproduce sexually. Sometimes members of this kingdom are called the “left-overs” or the “odds & ends” because they don’t seem to fit into any other kingdom. This kingdom includes all microscopic organisms that are not bacteria, not animals, not plants, and not fungi. Slime molds, algaes, such as plankton, and protozoans such as paramecia, euglena, and amoeba belong to this kingdom.