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The bacteria they are living beings unicellular and they are prokaryotic organisms. This means that its genetic material, a double-stranded circular DNA molecule, is free in the cytoplasm, not enclosed within a nucleus.
Since microfossils and stromatolites (fossil colonies of bacteria mixed with minerals) have been found in sediments from various geological eras, and even in sedimentary rocks older than 3.5 billion years, it is stated that bacteria have existed since very ancient times.
So much so that they have existed for a long period of Earth's history in which there were not even other forms of life. In fact, bacteria introduced very significant evolutionary events.
- See also:Viruses (biology)
Types of bacteria
It is usually distinguished today into two large groups:
- The bacteria: are represented by which predominate in the natural environment today, with the presence of different levels of oxygen and varied metabolisms.
- The Archaea: evolutionarily represent a previous category, with metabolisms specially adapted to extreme environmental situations, such as the lack of oxygen (remember that, according to rigorous studies, there was no oxygen on the planet until vegetables, the great oxygen liberators, appeared), or very saline or very acidic environments and high temperatures.
The great evolutionary success of bacteria is largely attributed to their surprising metabolic versatility. It can be said that all possible mechanisms of obtaining matter and energy they exist distributed in the diverse classes of bacteria.
- See also: Examples of Microorganisms
Examples of bacteria
| Escherichia coli | Bacillus thuringiensis |
| Bacillus subtilis | Clostridium botulinum |
| Mycobacterium tuberculosis | Clostridium tetani |
| Nitrobacter winogradsky | Pseudomonas aeruginosa |
| Thiobacillus ferooxidans | Falvobacterium aquatile |
| Rodospirillum rubrum | Azotobacter chroococcum |
| Chloroflexus aurantiacus | Neisseria gonorrhaea |
| Enterobacter aerogenes | Haemophilus influenza |
| Serratia marcescens | Yersinia enterocolitica |
| Salmonella typhi | Staphylococcus aureus |
Importance
The bacteria They have enormous importance in nature, since they are present in the natural cycles of the most important elements for life: nitrogen, carbon, phosphorus, sulfur, etc.
May transform organic substances into inorganic and vice versa. While many bacteria are pathogenic and cause disease in plants and animals (including humans).
Many others are used in various industrial processes, as the food and beverage processing alcoholic drugs, from antibiotics, etc.
characteristics
The bacteria They are microscopic and outside the membrane that encloses its cytoplasm there is a structure called the cell wall. More externally still, some bacteria form a gelatinous structure called capsule.
Bacteria reproduce by binary fission and very rapidly, so they are very abundant. Due to their highly varied metabolism, they can thrive in countless environments such as:
- Sweet and salty waters
- Organic material
- Ground
- Fruits and grains
- Plants
- Animals, both inside and on their surfaces
Many bacteria clump together forming pairs, chains or packages; they are often mobile; the flagellum (a species with a long appendage) is the structure that usually contributes to motility, but not the only one. The set of bacteria in culture is called a colony.
Follow with:
- Examples of Gram Positive and Gram Negative Bacteria
- Examples of Unicellular Organisms
- Examples of Prokaryotic and Eukaryotic Organisms
