Species is the unit of classification of living beings. You have seen the word "species" several times, but what does it really mean?
Think, for example, about the horse and the mare. They can mate and give birth to a fertile descendant, that is, who can also generate their own descendants. Therefore we say that horses and mares are animals that belong to the same species.
We can then define: species is a set of organisms similar to each other, capable of crossing and generating fertile descendants.
More related species than any other form a genre. The wild cat, found in all forests of Brazil, belongs to the species Leopardus wiedii; our ocelot, the largest of the small Brazilian wild cats, belongs to the species Leopardus pardalis; and the little bush cat, the smallest of the small wild cats in Brazil, belongs to the species Leopardus tigrinus.
All these animals are of different species, because they are NOT able to cross each other generating fertile descendants. But since these species are more related to each other than any others, they form a genus called Leopardus
In addition to gender, there are other grades of classification:
Species - Genus - Family - Order - Class - Phylum - Kingdom
- Similar genres form a larger group: the family.
- Families form the order.
- Orders form the class.
- The classes form the phylum
- Philos finally form the Kingdom.
To better understand the taxonomic categories, let's use the animal kingdom as a reference to the dog.
Among the phylum of chordates are, among others, animals that have a spine, known as vertebrates (as opposed to non-chords, called invertebrates). Among the chordates are amphibians, fish, reptiles, birds and mammals.
The set of rope and non-rope animal phyla forms the kingdom of animals - kingdom Animalia.
It is the most comprehensive group in the classification of living beings. Most researchers now accept five kingdoms:
Monera - Unicellular beings (formed by a single cell), prokaryotes (cells without organized nucleus, the simplest existing cell type). These are bacteria and cyanophytic algae or cyanobacteria (blue algae), formerly considered primitive vegetables.
Protist - Eukaryote unicellular beings (which have individualized nucleus). They have vegetable and animal characteristics. Represented by protozoa, such as amoeba, trypanosome (Chagas disease), plasmodium (malaria agent), euglena.
Fungus - Single and multicellular eukaryotes. They have already been classified as vegetables, but their membrane has chitin, a typical insect molecule that is not found among plants. They are heterotrophs (they do not produce their own food) because they do not have chlorophyll. They are represented by yeast, mold and mushrooms.
Plantae or Metaphite - These are vegetables, from green algae to higher plants. They are characterized by having cells coated with a cellulose membrane and being autotrophic (synthesize their own food by photosynthesis). There are about 400,000 classified vegetable species.
Animalia or Metazoa - They are multicellular and heterotrophic organisms (they do not produce their own food) because they are chlorophyllated. They range from marine sponges to humans.
One remark must be made: VIRUSES are beings that are classified separately and are considered as beings without a kingdom. This happens due to the unique characteristics that they present, such as the absence of cellular organization, lack of proper metabolism to obtain energy, reproduces only in host organism, among others. But they have the faculty to mutate in order to adapt to their surroundings.