Bacteroides and Escherichia are both gram-negative rods found in the large intestine. Why are they in different phyla?
To understand why Bacteroides and Escherichia are in different phyla, we need to delve into the classification of bacteria. Bacteria are classified based on their evolutionary relationships and shared characteristics. The classification of bacteria involves categorizing them into different taxonomic ranks, such as phylum, class, order, family, genus, and species.
Bacteroides and Escherichia belong to different phyla because they exhibit fundamental differences in their characteristics, primarily related to their cell wall composition and other physiological traits. The classification of bacteria is primarily based on the comparison of genetic information, particularly the sequencing of genes or whole genomes.
The phylum Bacteroidetes includes the genus Bacteroides. Bacteroides are anaerobic (meaning they can survive without oxygen) gram-negative bacteria. They typically have a complex cell wall structure that contains lipopolysaccharides and other unique components not found in other bacteria. Bacteroides are commonly found in the large intestine and play a significant role in human gastrointestinal health.
On the other hand, Escherichia belongs to the phylum Proteobacteria. Escherichia coli (E. coli) is a well-known species within this phylum. Proteobacteria are diverse and include a wide range of gram-negative bacteria with different shapes, sizes, and physiological characteristics. E. coli is a facultative anaerobe (can survive with or without oxygen) that also resides in the intestines of animals, including humans. It has a different cell wall composition compared to Bacteroides.
The distinction between Bacteroides and Escherichia being in different phyla arises from their genetic and physiological differences, particularly in terms of cell wall structure and other defining characteristics evaluated through genetic sequencing and analysis. This classification allows scientists to organize and understand the vast diversity of bacteria in a systematic and meaningful way.