Which kingdom includes autotrophs and heterotrophs

Bacteria are well-known for their metabolic diversity. Metabolism is a general term describing the complex biochemistry that occurs inside of cells. Many species of bacteria are autotrophs , meaning they can create their own food source without having to eat other organisms. Most autotrophic bacteria do this by using photosynthesis , a process that converts light energy into chemical energy that can be utilized by cells.

A well-known and ecologically-important group of photosynthetic bacteria is cyanobacteria. These are sometimes referred to a blue-green algae, but this name is not appropriate because, as you will see shortly, algae are organisms that belong to domain Eukarya. Cyanobacteria play important roles in food webs of aquatic systems, such as lakes. Other species of bacteria are heterotrophs , meaning that they need to acquire their food by eating other organisms. This classification includes the bacteria that cause disease in humans during an infection, the bacteria is eating you.

However, most heterotrophic bacteria are harmless to humans. In fact, you have hundreds of species of bacteria living on your skin and in your large intestine that do you no harm.

Beyond your body, heterotrophic bacteria play vital roles in ecosystems, especially soil-dwelling bacteria that decompose living matter and make nutrients available to plants. Figure 2. Many prokaryotes fall into three basic categories based on their shape: a cocci, or spherical; b bacilli, or rod-shaped; and c spirilla, or spiral-shaped.

Like bacteria, organisms in domain Archaea are prokaryotic and unicellular. Superficially, they look a lot like bacteria, and many biologists confused them as bacteria until a few decades ago. But hiding in their genes is a story that modern DNA analysis has recently revealed: archaeans are so different genetically that they belong in their own domain.

Many archaean species are found in some of the most inhospitable environments, areas of immense pressure bottom of the ocean , salinity such as the Great Salt Lake , or heat geothermal springs.

Organisms that can tolerate and even thrive in such conditions are known as extremophiles. It should be noted that many bacteria are also extremophiles. For whatever reason, archaeans are not as abundant in and on the human body as bacteria, and they cause substantially fewer diseases.

Research on archaeans continues to shed light on this interesting and somewhat mysterious domain. This domain is most familiar to use because it includes humans and other animals, along with plants, fungi, and a lesser-known group, the protists. Unlike the other domains, Domain Eukarya contains multicellular organisms, in addition to unicellular species. The domain is characterized by the presence of eukaryotic cells. For this domain, you will be introduced to several of its kingdoms.

What classification is a worm? Why is classification important in biology? How does domain eukarya differ from domain bacteria and domain archaea? What are some examples of domain archaea? How do domain archaea and domain bacteria differ? See all questions in Classification and Domains of Life. The word heterotroph comes from the Greek "heteros," which means "other" or "different," and "trophe," which means "nutrition. This means eating or absorbing sources of organic carbon.

All animals and fungi are heterotrophs. Autotrophs, on the other hand, that create their own food by fixing carbon. In other words, autotrophs get their carbon directly from carbon dioxide, which they use to create organic carbon compounds for use in their own cells.

All plants and some bacteria, archaea, and protists obtain their carbon in this way. Scientists divide heterotrophs into two basic categories: photoheterotrophs and chemoheterotrophs. Photoheterotrophs still get their carbon from organic sources, but they also get energy from sunlight. This grouping includes certain types of green bacteria and purple bacteria. Chemoheterotrophs, also called organotrophs, get both their energy and their carbon from organic sources.

Animals and fungi fall into this category.