Taxonomy (Biology) Part-I

Antony Van Leeuwenhoek is regarded as the father of microbiology. He is known for the discovery of bacteria. He was born on October 24, 1632 in Delft, Netherlands.

In the late 17th century, Leeuwenhoek began observing microorganisms in various samples, including pond water, his own saliva, and other substances. He meticulously described the shapes, sizes, and movements of these tiny organisms, which he initially called "animalcules".

His meticulous observations and descriptions laid the foundation for the field of microbiology, which is the study of microorganisms.

Leeuwenhoek was not only a keen observer but also a skilled craftsman, building microscopes that were significantly more powerful than those available at the time.

Bacteria have a wide range of diets. Some are heterotrophs and others are autotrophs. Most heterotrophic bacteria are saprobes (they absorb dead organic material like rotting flesh). Some of these parasitic bacteria kill their host while others help their host.

Autotrophic bacteria make their own food, either by photosynthesis (which uses sunlight, carbon dioxide, and water to make food) or by chemosynthesis (which uses carbon dioxide, methane, and chemicals like ammonia, hydrogen sulphide to make food).

Phototrophic bacteria do not have chloroplast. Bacteriochlorophylls are photosynthetic pigments that occur in various phototrophic bacteria.

Bacteria are universal, can be found everywhere. There are some harmful bacteria that can cause illness and disease.

There are other bacteria that are essential for us to survive. Bacteria in the digestive system also supply needed vitamins like biotin and vitamin K and are our primary source for some of these nutrients.

Gram-positive bacteria possess a thick cell wall containing many layers of peptidoglycan and teichoic acids.

In contrast, Gram-negative bacteria have a relatively thin cell wall consisting of a few layers of peptidoglycan surrounded by a second lipid membrane containing lipopolysaccharides and lipoproteins.

Mycoplasma is the smallest known organism, capable of autonomous growth and reproduction. Mycoplasmas are incredibly tiny, with diameters ranging from 0.2 to 0.3 microns (0.2 to 0.3 micrometers), making them one of the smallest free-living organisms.

They have the ability to grow and reproduce independently, meaning they don't require a host cell to survive and replicate, unlike some other microorganisms like viruses.

Mycoplasmas lack a rigid cell wall, which distinguishes them from other bacteria and places them in a separate class called Mollicutes. This lack of a cell wall makes them sensitive to osmotic changes and some antibiotics.

They have a relatively simple cell structure, including a plasma membrane, ribosomes, and a small genome, consisting of a double-stranded circular DNA molecule.

While small, Mycoplasmas can be pathogenic, causing infections in various animals, including humans. They are found in a wide variety of environments, including humans, animals, plants, and even some marine environments.

Amoeba is an unicellular organism which has the ability to alter its shape, primarily by extending and retracting pseudopods.

Amoeba reproduces by fission. Binary fission is a type of asexual reproduction practiced by unicellular organisms in which the parent cell divides into two daughter cells.

Generally unicellular organisms reproduce by asexual methods only, while some unicellular eukaryotes (like Paramecium) are capable of both asexual and sexual reproduction.

Viruses require a living host cell for replication. They cannot be cultured in artificial/synthetic medium due to lack of metabolic machinery of their own.

Viruses can be grown in vivo (within a whole living organism, plant, or animal) or in vitro (outside a living organism in cells in an artificial environment). Infected host cells (eukaryotic or prokaryotic) can be cultured and grown, and then the growth medium can be harvested as a source of virus.