- What is an organism?
- Organism types
- Autotrophic and heterotrophic organism
- Human organism
- Examples of organism
We explain what an organism is, how it is classified, autotrophic and heterotrophic organism. Also, human organism and examples.
What is an organism?
In biology, an organism or living being is called a singular and differentiated individual, composed of a set of organic material hierarchical and specialized. It is made up of transmission systems and communication biochemistry, which allow you to maintain your internal balance while exchanging matter Y Energy with the environment that surrounds it. In other words, an organism is a living entity, endowed with the ability to nurture, grow, reproduce and die.
All known organisms, with the exception of the virus, are formed by cells, and have a metabolism that allows them to guarantee their existence and give rise to their biological processes in exchange for exchanging energy with the environment. The ultimate goal of every organism seems to be the reproduction, that is, the perpetuation of its species and the transmission of his genetic material (inheritance).
Chemically speaking, living beings are distinguished from the nature that surrounds them in its almost exclusive composition based on carbon, hydrogen, oxygen and nitrogen, that is, based on molecules organic, structured very differently from the inorganic molecules of the inert matter.
Organism types
Organisms are classified according to various criteria. The main criterion is bodily and physiological similarity, and their belonging to a specific evolutionary group that shares a common ancestor (a taxon). According to this criterion, living beings can belong to five kingdoms of life differentiated, grouped in turn into two different domains or super realms:
- Prokaryota domain. In this domain are the most primitive known organisms, all unicellular and devoid of cell nucleus, that is, with molecules of DNA circular, simple and loose in the cytoplasm cell phone. They are the oldest living beings evolutionarily and the simplest and smallest. In this domain two kingdoms are identified:
- Bacteria kingdom. In this kingdom are the prokaryotes most abundant of the planet, the bacteria, adapted to almost all habitats and to various life models based on photosynthetic, chemosynthetic, parasitic metabolisms, etc.
- Archaea kingdom. Archaebacteria or archaea gained their reputation as a separate kingdom in relatively recent times, when it was discovered that they possess metabolic pathways and biochemical characteristics more similar to those of the eukaryotes. They are usually adapted to very demanding environments with the life, such as extreme niches such as salt flats, hot springs, etc. Depending on the classification used, archaea can constitute, like bacteria, an individual domain.
- Eukaryota domain. The second domain of life is made up of single-celled organisms Y multicellular whose cells, larger and more complex, are equipped with a cell nucleus in which DNA resides, in the shape of a double helix, as well as other similar organelles. They are an evolutionary step forward with respect to prokaryotes and, thanks to this, they allowed the existence of multicellular beings. In this domain four kingdoms are identified:
- Protist kingdom. Protists are eukaryotic unicellular organisms, which would become the link between prokaryotes and multicellular organisms. In this kingdom there are various types of living beings, both autotrophs What heterotrophs, that is, what do they do photosynthesis or that they feed on other living things, including parasites that cause disease.
- Kingdom plantae. This is the kingdom of plants, that is, of multicellular organisms (with the exception of some algae) that carry out photosynthesis: the transformation of the CO2 and the solar energy in starches that serve for the growth and maintenance of the organism. For this they are endowed with chlorophyll, a pigment that gives them their color characteristic green.
- Fungi kingdom. The kingdom of fungi, which share cellular characteristics with plants (such as the presence of the cell wall, but of chitin instead of cellulose) and with animals (such as their heterotrophic nutrition, from the organic material decomposing). Except the yeast, which are unicellular, are always multicellular and reproduce by means of spores.
- Animalia Kingdom. The kingdom of animals, the only living beings endowed with voluntary mobility, in its enormous diversity, from insects, worms and snails, to amphibians, reptiles, birds and mammals. Animals reproduce sexually and their metabolisms operate on the basis of oxidation glucose, for which they must breathe oxygen from the air or of Water (using lungs or gills).
Autotrophic and heterotrophic organism
Decomposing organisms are considered heterotrophs.
An important and common differentiation to all types of living beings is the one that distinguishes between living beings capable of synthesizing their own nutrients (autotrophs) and those that are not capable of doing so and must consume the organic matter of other living beings (heterotrophs) .
Among the living beings of the first type, we find plants and those microorganisms capable of chemically synthesizing their nutrients (chemosynthesis) using extreme environmental conditions. These organisms are known as producers in their respective ecosystems and they are usually found at the base of the food pyramid.
Living beings with heterotrophic metabolism, on the other hand, are the most diverse and make up various trophic levels above the producers. In the first level are those herbivores that obtain their raw material from the consumption of plants, their fruits or derivatives. The second level is constituted by the predators that feed on the herbivores, which are generally small. And finally, on the third level are the great predators that feed on other predators and herbivores, and are the end of the chain.
Finally, decomposing organisms (such as fungi, insects, scavengers and bacteria) are also heterotrophs that serve to help decompose residual organic matter, acting as the recycling department of the nature.
Human organism
The human organism is the only one of known nature that possesses full awareness of itself and an intelligence that allows it to modify the environment in its favor, instead of adapting itself to the challenges of the environment. The human being is the product of billions of years of evolution continues, which threw the first Homo sapiens about 2 million years ago.
Our body is multicellular (it is made up of almost 100 trillion cells) and it is made up 50% of water. We are mammalian living beings, bipedal, bilaterally symmetrical and vertebrates, with oxygen-dependent metabolisms (breathing) and glucose, which we ingest from an omnivorous diet.
Examples of organism
Any living being on the planet is a perfect example of an organism or a living being. This includes plants such as algae, ferns, fruit trees, or shrubs. plain and the cacti of the desert; also the fungi that we see in the I usually of the woods or in the roots of the trees (mycorrhizae), or those so annoying that afflict athletes between their toes; also animals of all kinds, marine, terrestrial and flying, the human being himself, and the bacterial flora that makes life in our intestine, in a symbiotic relationship with our body. Wherever there is life, we can identify an organism.