Virus, Parasite, and Fungi all use a host for pure personal gain. Some strains of bacteria are beneficial, and are ingested regularly in the form of probiotics.
Autotrophs make their own food. Typically, we think of plants as autotrophs, and this is true, but there are other kinds as well. Plants, algae, phytoplankton, and some bacteria are photosynthetic, meaning they use sunlight to make sugar, which they then use to make energy. Photosynthetic organisms are green because they contain a pigment called chlorophyll that does photosynthesis. Some other types of bacteria are also autotrophic, but they are chemosynthetic.
They use the energy stored in chemicals, usually released from deep sea vents, to make their food, and then energy.
Green leaves make food through photosynthesis leaf Autotrophs form the basis of all food webs.
They gather energy from inorganic sources, like chemicals or the sun, and convert it into a form that other animals can use. Energy is transferred from the autotrophs to consumers that eat them, and then to carnivores that eat those animals. Without autotrophs, all of our food webs would collapse.
