揭示微生物群落的等级结构

The “tree of life” describes the evolution of life and the evolutionary relationships between organisms. The root of the tree is the common ancestor to all life on Earth. All other species radiate from this point, much like the branches of a tree. The numerous tips of these branches on the tree of life represent every living, or extant, species. Extinct species, which are species that no longer exist, can be found towards the center of the tree. Currently, these organisms, both...

All organisms in an ecosystem occupy a trophic level in the food chain. The lowest level consists of primary producers, which synthesize their food from either solar or chemical energy. Each subsequent level obtains energy from the levels below. Detritivores can occupy any of the levels above primary producers.

Prokaryotes are small unicellular organisms that include the domains—Archaea and Bacteria. Bacteria include many common organisms, such as Salmonella and E. coli, while the Archaea include extremophiles that live in harsh environments, such as volcanic springs.
Like eukaryotic cells, all prokaryotic cells are surrounded by a plasma membrane, have genetic material in the form of single, circular DNA, a cytoplasm that fills the interior of the cell, and ribosomes that synthesize proteins....

Genome comparison is one of the excellent ways to interpret the evolutionary relationships between organisms. The basic principle of genome comparison is that if two species share a common feature, it is likely encoded by the DNA sequence conserved between both species. The advent of genome sequencing technologies in the late 20th century enabled scientists to understand the concept of conservation of domains between species and helped them to deduce evolutionary relationships across diverse...