As bacteria modified structures to expand their territory and tolerance, they changed into newer species of bacteria with diverse structures and functions. Due to their uniqueness, bacteria are classified in their own kingdom! Advancements in the structure and function of prokaryotes continued to the juncture where two separate types are now identifiable: bacteria and archaea.
Bacteria are the most common and well studied because they are the easiest to find and have historically been the source of many human maladies, such as bubonic plague, tuberculosis, and cholera, and the source of much advancement such as cheese, recombinant DNA, and intestinal flora, which aids in digestion and nutrient production. Even today, anabaena, a typical cyanobacteria, blooms in nutrient overloaded aquatic environments to produce a telltale blue-green color.
Environmentalists use anabaena blooms as an indicator of environmental quality. Bacteria appear to be simpler than archaea because they do not possess certain advanced structures typical in archaea, such as the complex RNA polymerase, the presence of interons, and branched carbon chains in lipid membranes, as well as some internal membranes.
However, they do possess a cell membrane and have definite life functions. They exist alone or in colonies, in a variety of shapes, and some can endure unfavorable conditions by forming a protective endospore around the cell, which allows the cell to remain viable and dormant until favorable conditions arrive.
Bacteria and archaea do possess whiplike flagella for movement. Cyanobacteria, also known as blue-green algae, are intriguing organisms because they contain photosynthetic capabilities and are thought to be responsible for changing the prehistoric environment to an oxygen atmosphere. Microfossil cyanobacteria estimated to be 3. Their hypothesized oxygen production likely also created the protective ozone layer. Archaea have structures such as tRNA nucleotide sequences and RNA polymerase that are more closely related to eukaryotes than bacteria.
They have adapted complex protein, carbohydrate, and lipid molecules that allow them to live and reproduce in the harshest environments where nothing else will live. In fact, archaea are so different from bacteria that they are also classified in their own kingdom, separate from all other organisms! Many species are autotrophic and obtain energy through the chemosynthesis of carbon dioxide instead of the photosynthesis of carbon dioxide.
Because of their extreme lifestyle, they do not have the history of scientific investigation that bacteria have generated, although they contain the solutions for expanding the genetic territory of other helpful microorganisms. For example, archaebacteria thrive in the hot springs in Yellowstone National Park where the water temperature is measured at F 90C. Moulton, Ed. All rights reserved including the right of reproduction in whole or in part in any form.
It is also suggested that continued membrane infolding created the endomembrane system. It can be said that possibly the first eukaryotic cell type was miraculously born from prokaryotic, symbiotic, multicell interactions! Moulton, Ed. All rights reserved including the right of reproduction in whole or in part in any form.
To order this book direct from the publisher, visit the Penguin USA website or call You can also purchase this book at Amazon. See also:. Origin of Prokaryotes and Eukaryotes: Protists. Delete Cancel. Mitochondria and chloroplasts likely evolved from engulfed prokaryotes that once lived as independent organisms. At some point, a eukaryotic cell engulfed an aerobic prokaryote, which then formed an endosymbiotic relationship with the host eukaryote, gradually developing into a mitochondrion.
Eukaryotic cells containing mitochondria then engulfed photosynthetic prokaryotes, which evolved to become specialized chloroplast organelles. This image is linked to the following Scitable pages:.
Eukaryotic cells are more complex than prokaryotic ones because of specialized organelles. Learn how ancient collaborations between cells gave eukaryotes an important energy boost. All cells evolved from a common ancestor and use the same kinds of carbon-based molecules. Learn how cell function depends on a diverse group of nucleic acids, proteins, lipids, and sugars.
Plant cells have some specialized properties that make them distinct from animal cells. Learn how special structures, such as chloroplasts and cell walls, create this distinction. Comments Close.
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