The multicellular organisms are all living creatures which are composed from two or more cells, this represents the majority of living organisms on the planet. The cells that make up this type of organisms reproduce through processes such as meiosis or mitosis , which in turn allows various types of processes to occur, all the cells in question differ according to their functions and other factors but they need of the others in a mutual way to be able to sustain themselves and live.
When cells come from the same origin they are grouped together forming tissues, these tissues fulfill various functions such as the following:
- the epithelial function is one that covers surfaces and also integrates different glands responsible for the secretion of substances.
- the conjunctive function is one that has the function of keeping internal organs together.
- the cartilaginous function is in charge of establishing the structure of parts of a body.
- the Adipose function meets the objective of reserve energy
- the bone function is responsible for generating a structure like the skeleton,
- the muscular function allows contraction and spread to the limbs and other parts of the body.
- the nervous function perceives stimuli to which an organism is exposed and responds to them,
- finally the blood function is responsible for transporting CO2, O2 and nutrients.
It should be noted that multicellular organisms not only refer to large beings such as animals, humans or plants and trees, but also small beings such as some bacteria and other microorganisms that do not necessarily have tissues such as algae and fungi.
There are also those organisms with tissues that need to be connected to others for the formation of organs, which is seen more frequently in beings with a more complex cellular structure. Regarding its origin, there is no strong theory but several that are being considered, one of them and the most accepted is the possible symbiosis that occurred between unicellular beings within the same species, which with the passage of time gave way to multicellular organisms.
Examples of multicellular organisms
- The shark is a multicellular organism that inhabits many oceans.
- The rattlesnake is a rattlesnake belonging to the group of reptiles.
- The squid is a mollusccephalopod found in many oceans.
- The bear is a multicellular vertebrate being that is found within the animal kingdom, carnivore and of the ursidae family.
- The human being is one of the most complex multicellular organisms and belongs to the animal kingdom, it is a placental mammal and it belongs to the homo sapiens species.
- Spiders and other arachnids
- The bee and the wasps
- The owl
- The human body
- Green lizard