Invisible diversity: the many forms of bacteria
Bacteria are surprising.
They were the first life form to appear on Earth almost 3.8 billion years old from.
They are the second most abundant form of life, only surpassed by plants.
And most interesting of all: they exist in virtually every environment on our planet, including areas where no other form of life can survive. As a result, bacteria exhibit a wide variety of similar appearances, behaviors and applications to the life forms we see in our daily lives.
The incredible diversity of bacteria is underestimated simply because they are invisible to the naked eye. Here we illustrate how researchers classify these creatures based on their appearance, giving you a glimpse into this microscopic world.
A cultural life
Although bacteria may resemble other microorganisms like fungi or plankton, they are quite unique at the microscopic and genetic level.
Bacteria are one of the three main domains of life. All life shares its oldest ancestor with this group of microbes, alongside two other realms: the Archaea and the Eukarya.
Archaea are very similar to bacteria, but have different contents that make up their cell walls.
Eukarya consists largely of complex, multicellular life, such as fungi, plants, and animals. Bacteria are similar to its single-celled members as all bacteria are also single-celled. However, while all Eukarya have nuclear membranes that store genetic material, bacteria do not.
Bacteria have their genetic material floating freely in their cell bodies. This impacts how their genes are coded, how proteins are synthesized, and how they reproduce. For example, bacteria do not reproduce sexually. Instead, they reproduce on their own.
Bacteria undergo a process called binary fission, where any one cell splits into two identical cells, and so on. Fission occurs rapidly. Within minutes, populations can rapidly double, eventually forming a community of genetically identical microbes called colony.
Colonies can be visible to the naked eye and can take on different shapes, textures, sizes, colors and behaviors. You may know some of them:
Small World Superstars
Here are some interesting bacterial species, some of which you may be familiar with:
Epulopiscium spp
This species is exceptionally large, ranging from 200 to 700 micrometers in length. They are also incredibly picky, living only in the guts of sturgeon, a type of large fish.
Deinococcus radiodurans
D. radiodurans is a coccus-shaped species that can withstand 1,500 times the radiation dose that a human can withstand.
Escherichia coli
Although they have been known to poison food and agricultural areas from time to time, all E.coli species are dangerous.
Desulfurudis audaxviator
In the depths of a South African gold mine, this species thrives without oxygen, sunlight or friends – it is the only living species in its ecosystem. It survives by eating minerals in the surrounding rock.
Helicobacter pylori
Known to cause stomach ulcers, this spiral-shaped species has also been linked to many cancers that affect lymphoid tissue.
Planococcus halocryophilus
Most living things stop surviving cold temperatures, but P. halocryophilus thrives in High Arctic permafrost where temperatures can drop below -25°C/-12°F.
‘Bact’ to the future
Despite their microscopic size, the contributions of bacteria to our daily lives are enormous. Researchers use them every day to study new environments, create new drug therapies, and even create new materials.
Scientists can profile the diversity of species living in a habitat by extracting DNA from an environmental sample. Known as metagenomics, this area of genetics commonly studies bacterial populations.
In habitats without oxygen, bacteria constantly find alternative sources of energy. Some have even evolved into eat plastic or metal dumped in the ocean.
The health industry uses bacteria to create antibiotics, vaccines and other metabolic products. They also play a major role in a new range of self-build materials, which includes ‘self-healing’ concrete and ‘living bricks’.
These are just a few of the many examples in which bacteria impact our daily lives. Although they are invisible, without them our world would undoubtedly look like a much different place.
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