Evolution of bacteria

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Colorized scanning electron micrograph showing carbapenem-resistant Klebsiella pneumoniae interacting with a human neutrophil. Klebsiella pneumoniae Bacterium (13383411493).jpg
Colorized scanning electron micrograph showing carbapenem-resistant Klebsiella pneumoniae interacting with a human neutrophil.

The evolution of bacteria has progressed over billions of years since the Precambrian time with their first major divergence from the archaeal/eukaryotic lineage roughly 3.2-3.5 billion years ago. [1] [2] This was discovered through gene sequencing of bacterial nucleoids to reconstruct their phylogeny. Furthermore, evidence of permineralized microfossils of early prokaryotes was also discovered in the Australian Apex Chert rocks, dating back roughly 3.5 billion years ago [3] during the time period known as the Precambrian time. This suggests that an organism in of the phylum Thermotogota (formerly Thermotogae) [4] was the most recent common ancestor of modern bacteria.

Contents

Further chemical and isotopic analysis of ancient rock reveals that by the Siderian period, roughly 2.45 billion years ago, [5] oxygen had appeared. This indicates that oceanic, photosynthetic cyanobacteria evolved during this period because they were the first microbes to produce oxygen as a byproduct of their metabolic process. [6] Therefore, this phylum was thought to have been predominant roughly 2.3 billion years ago. However, some scientists argue they could have lived as early as 2.7 billion years ago, [7] as this was roughly before the time of the Great Oxygenation Event, meaning oxygen levels had time to increase in the atmosphere before it altered the ecosystem during this event.

The rise in atmospheric oxygen led to the evolution of Pseudomonadota (formerly proteobacteria). Today this phylum includes many nitrogen fixing bacteria, pathogens, and free-living microorganisms. This phylum evolved approximately 1.5 billion years ago during the Paleoproterozoic era. [8]

However, there are still many conflicting theories surrounding the origins of bacteria. Even though microfossils of ancient bacteria have been discovered, some scientists argue that the lack of identifiable morphology in these fossils means they can not be utilised to draw conclusions on an accurate evolutionary timeline of bacteria. Nevertheless, more recent technological developments means more evidence has been discovered.

Defining bacteria

Bacteria are prokaryotic microorganisms that can either have a bacilli, spirilli, or cocci shape and measure between 0.5-20 micrometers. They were one of the first living cells to evolve [9] and have spread to inhabit a variety of different habitats including hydrothermal vents, glacial rocks, and other organisms. They share characteristics with eukaryotic cells including the cytoplasm, cell membrane, and ribosomes. Some unique bacterial features include the cell wall (also found in plants and fungi), flagella (not common for all bacteria), and the nucleoid.[ citation needed ]

Bacteria can metabolise in different ways, most commonly by heterotrophic or autotrophic (either photosynthetic or chemosynthetic) processes. Bacteria reproduce through binary fission, though they can still share genetic information between individuals either by transduction, transformation, or conjugation.[ citation needed ]

Process of bacterial evolution

Bacteria evolve in a similar process to other organisms. This is through the process of natural selection, whereby beneficial adaptations are passed onto future generations until the trait becomes common within the entire population. [10] However, since bacteria reproduce via binary fission—a form of asexual reproduction—the daughter cell and parent cell are genetically identical. This makes bacteria susceptible to environmental pressures, an issue that is overcome by sharing genetic information via transduction, transformation, or conjugation. This allows for new genetic and physical adaptations to develop, allowing bacteria to adapt to their environment and evolve. Furthermore, bacteria can reproduce in as little as 20 minutes, [11] which allows for fast adaptation, meaning new strains of bacteria can evolve quickly. This has become an issue regarding antibiotic resistant bacteria.[ citation needed ]

Thermophile bacteria from deep-sea vent. This organism eats sulfur and hydrogen and fixes its own carbon from carbon dioxide. Thermophile bacteria2.jpg
Thermophile bacteria from deep-sea vent. This organism eats sulfur and hydrogen and fixes its own carbon from carbon dioxide.

Thermotogales

Thermotogota bacteria are typically thermophilic or hyperthermophilic, gram-negative staining, anaerobic organisms that can live near hydrothermal vents where temperatures can range between 55-95 °C. They are thought to be some of the earliest forms of life. Evidence of these organisms has been discovered in the Australian Apex Chert near ancient hydrothermal vents. [12] [13] These rocks date back 3.46 billion years and these fossils are thought to have belonged to early thermophilic bacteria. This is because these organisms do not require oxygen to survive, which was an element that was not present in large quantities in Earth's early atmosphere. [14] Furthermore, this phylum still has living species such as Thermotoga neapolitana , which still largely resemble their ancestral form and still live around these vents, which some scientists have used as evidence to support this theory.[ citation needed ]

More recent evidence has emerged, which suggests that Thermotogales evolved roughly between 3.2-3.5 billion years ago. This evidence was collected via gene sequencing of bacterial nucleoids to reconstruct their phylogeny. [1] [2] The first major divergence within the Thermotogales phylum was between Thermotogaceae and Fervidobacteriaceae, however, it is yet to be determined as to when this occurred. The family of Thermotogaceae then diverged into the genus Thermotoga and the genus Pseudothermotoga . [15] The genus Thermotoga represents the majority of existing hyperthermophiles and are unique in that they are wrapped in an outer membrane that is referred to as a "toga". Some extant Thermotoga species include T. neapolitana.[ citation needed ]

Thermotogale phylogeny

Colourful Thermophilic (Heat-loving) Archaebacteria Stain. Archaebacteria are nowadays regarded as their own domain Archaea, distinct from Thermotogales. Colourful Thermophilic Archaebacteria Stain in Midway Geyser Basin.jpg
Colourful Thermophilic (Heat-loving) Archaebacteria Stain. Archaebacteria are nowadays regarded as their own domain Archaea, distinct from Thermotogales.

The phylogeny based on the work of the All-Species Living Tree Project. [15]

Thermotogales
Thermotogaceae
Thermotoga

T. naphthophila

T. petrophila

T. maritima (type sp.)

T. neapolitana

Pseudothermotoga

P. hypogea

P. thermarum

P. subterranea

P. elfii

P. lettingae

Fervidobacteriaceae
Fervidobacterium

F. changbaicum

F. islandicum

F. nodosum (type sp.)

F. gondwanense

F. riparium

Thermosipho

T. activus

T. geolei

T. atlanticus

T. affectus

T. melanesiensis

T. globiformans

T. africanus (type sp.)

T. japonicus

Cyanobacteria

Cyanobacteria or blue green-algae is a gram negative bacteria, a phylum of photosynthetic bacteria that evolved between 2.3-2.7 billion years ago. [16] This prokaryote produces oxygen as a byproduct of its photosynthetic processes. [17] They have made a distinctive impact in pharmaceutical and agricultural industry due to their potential of making bioactive compounds with antibacterial, anti-fungal, antiviral, and anti-algal properties. Typically they form motile filaments referred to as hormogonia, which can form colonies and then bud and travel to colonise new areas. They have been located in environments including freshwater, oceans, soil and rock (both damp and dry), as well as arctic rock.[ citation needed ]

These organisms had evolved photosynthetic reaction centres and became the first oxygen producing autotrophs to appear in the fossil record. They utilise sunlight in order to drive their metabolic processes, which removes carbon dioxide from the atmosphere and releases oxygen. [18] Due to this trait some scientist credit this phylum to causing the Great Oxygenation Event roughly 2.3 billion years ago [19]

English: Bloom of cyanobacteria in a freshwater pond. This accumulation in one corner of the pond was caused by wind drift. It looked as if someone had dumped a bucket color into the water. Cyanobacteria Aggregation2.jpg
English: Bloom of cyanobacteria in a freshwater pond. This accumulation in one corner of the pond was caused by wind drift. It looked as if someone had dumped a bucket color into the water.

However, the closest known relatives of oxygen producing Cyanobacteria did not produce oxygen. [20] These relatives are Melainabacteria and Sericytochromatia, neither of which can photosynthesise. Through genetic sequencing, scientists discovered that these two groups did not have any remnants of the genes required for the functioning of photosynthetic reactions. [20] This suggests that Cyanobacteria, Melainabacteria, and Sericytochromatia evolved from a non-photosynthetic common ancestor.[ citation needed ]

Related Research Articles

<span class="mw-page-title-main">Cell (biology)</span> Basic unit of many life forms

The cell is the basic structural and functional unit of all forms of life. Every cell consists of cytoplasm enclosed within a membrane; many cells contain organelles, each with a specific function. The term comes from the Latin word cellula meaning 'small room'. Most cells are only visible under a microscope. Cells emerged on Earth about 4 billion years ago. All cells are capable of replication, protein synthesis, and motility.

<span class="mw-page-title-main">Photosynthesis</span> Biological process to convert light into chemical energy

Photosynthesis is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their activities. Photosynthetic organisms use intracellular organic compounds to store the chemical energy they produce in photosynthesis. Photosynthesis is usually used to refer to oxygenic photosynthesis, a form of photosynthesis where the photosynthetic processes produce oxygen as a byproduct and synthesize carbohydrate molecules like sugars, starches, glycogen, and cellulose to store the chemical energy. To use the chemical energy stored in these organic compounds, the organisms' cells metabolize the organic compounds through another process called cellular respiration. Photosynthesis is largely responsible for producing and maintaining the oxygen content of the Earth's atmosphere, and it supplies most of the biological energy necessary for complex life on Earth.

<span class="mw-page-title-main">Symbiogenesis</span> Evolutionary theory holding that eukaryotic organelles evolved through symbiosis with prokaryotes

Symbiogenesis is the leading evolutionary theory of the origin of eukaryotic cells from prokaryotic organisms. The theory holds that mitochondria, plastids such as chloroplasts, and possibly other organelles of eukaryotic cells are descended from formerly free-living prokaryotes taken one inside the other in endosymbiosis. Mitochondria appear to be phylogenetically related to Rickettsiales bacteria, while chloroplasts are thought to be related to cyanobacteria.

<span class="mw-page-title-main">Cyanobacteria</span> Phylum of photosynthesising prokaryotes that can produce toxic blooms in lakes and other waters

Cyanobacteria, also called Cyanobacteriota or Cyanophyta, are a phylum of autotrophic gram-negative bacteria that can obtain biological energy via photosynthesis. The name 'cyanobacteria' refers to their color, which similarly forms the basis of cyanobacteria's common name, blue-green algae, although they are not scientifically classified as algae. They appear to have originated in a freshwater or terrestrial environment.

<span class="mw-page-title-main">Plastid</span> Plant cell organelles that perform photosynthesis and store starch

A plastid, pl. plastids, is a membrane-bound organelle found in the cells of plants, algae, and some other eukaryotic organisms;. They are considered to be intracellular endosymbiotic cyanobacteria.

<span class="mw-page-title-main">Unicellular organism</span> Organism that consists of only one cell

A unicellular organism, also known as a single-celled organism, is an organism that consists of a single cell, unlike a multicellular organism that consists of multiple cells. Organisms fall into two general categories: prokaryotic organisms and eukaryotic organisms. Most prokaryotes are unicellular and are classified into bacteria and archaea. Many eukaryotes are multicellular, but some are unicellular such as protozoa, unicellular algae, and unicellular fungi. Unicellular organisms are thought to be the oldest form of life, with early protocells possibly emerging 3.8–4.8 billion years ago.

<i>Chloroflexus aurantiacus</i> Species of bacterium

Chloroflexus aurantiacus is a photosynthetic bacterium isolated from hot springs, belonging to the green non-sulfur bacteria. This organism is thermophilic and can grow at temperatures from 35 °C to 70 °C. Chloroflexus aurantiacus can survive in the dark if oxygen is available. When grown in the dark, Chloroflexus aurantiacus has a dark orange color. When grown in sunlight it is dark green. The individual bacteria tend to form filamentous colonies enclosed in sheaths, which are known as trichomes.

<span class="mw-page-title-main">Marine life</span> Organisms that live in salt water

Marine life, sea life, or ocean life is the plants, animals, and other organisms that live in the salt water of seas or oceans, or the brackish water of coastal estuaries. At a fundamental level, marine life affects the nature of the planet. Marine organisms, mostly microorganisms, produce oxygen and sequester carbon. Marine life, in part, shape and protect shorelines, and some marine organisms even help create new land.

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Bacteria are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria play a vital role in many stages of the nutrient cycle by recycling nutrients and the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. Bacteria also live in mutualistic, commensal and parasitic relationships with plants and animals. Most bacteria have not been characterised and there are many species that cannot be grown in the laboratory. The study of bacteria is known as bacteriology, a branch of microbiology.

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<span class="mw-page-title-main">Marine microorganisms</span> Any life form too small for the naked human eye to see that lives in a marine environment

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<span class="mw-page-title-main">Archean life in the Barberton Greenstone Belt</span> Some of the most widely accepted fossil evidence for Archean life

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The evolution of photosynthesis refers to the origin and subsequent evolution of photosynthesis, the process by which light energy is used to assemble sugars from carbon dioxide and a hydrogen and electron source such as water. The process of photosynthesis was discovered by Jan Ingenhousz, a Dutch-born British physician and scientist, first publishing about it in 1779.

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<span class="mw-page-title-main">Marine prokaryotes</span> Marine bacteria and marine archaea

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References

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  2. 1 2 Brown, J R Doolittle, W F (December 1997). "Archaea and the prokaryote-to-eukaryote transition". Microbiology and Molecular Biology Reviews. 61 (4): 456–502. doi:10.1128/mmbr.61.4.456-502.1997. PMC   232621 . PMID   9409149.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  3. ↑ "31. Ancient Life: Apex Chert Microfossils". www.lpi.usra.edu. Retrieved 2019-05-21.
  4. ↑ Di Giulio, Massimo (December 2003). "The Universal Ancestor and the Ancestor of Bacteria Were Hyperthermophiles". Journal of Molecular Evolution. 57 (6): 721–730. Bibcode:2003JMolE..57..721D. doi:10.1007/s00239-003-2522-6. PMID   14745541. S2CID   7041325.
  5. ↑ Zimmer, Carl (2013-10-03). "The Mystery of Earth's Oxygen". The New York Times. Retrieved 2019-05-21.
  6. ↑ "The Rise of Oxygen". Astrobiology Magazine. 2003-07-30. Archived from the original on 2015-09-06. Retrieved 2019-05-21.{{cite web}}: CS1 maint: unfit URL (link)
  7. ↑ "When Did Bacteria Appear?". Astrobiology Magazine. 2004-04-18. Archived from the original on 2019-01-12. Retrieved 2019-05-21.{{cite web}}: CS1 maint: unfit URL (link)
  8. ↑ Degli Esposti, Mauro (2014-11-27). "Bioenergetic Evolution in Proteobacteria and Mitochondria". Genome Biology and Evolution. 6 (12): 3238–3251. doi: 10.1093/gbe/evu257 . PMC   4986455 . PMID   25432941.
  9. ↑ Hartman, H; Matsuno, K (1993). The Origin and Evolution of the Cell. World Scientific. pp. 1–446. doi:10.1142/9789814536219. ISBN   9789810212629.
  10. ↑ "Evolution Resources from the National Academies". www.nas.edu. Archived from the original on 2016-06-03. Retrieved 2019-05-21.
  11. ↑ "About Microbiology – Bacteria". microbiologyonline.org. Archived from the original on 2019-11-27. Retrieved 2019-05-21.
  12. ↑ Brasier, M. D. (2011). Geology and putative microfossil assemblage of the c. 3460 Ma 'Apex Chert', Chinaman Creek, Western Australia : a field and petrographic guide. Geological Survey of Western Australia. ISBN   9781741683660. OCLC   748237320.
  13. ↑ "Apex Chert Microfossils". ResearchGate. Retrieved 2019-05-21.
  14. ↑ Frock, Andrew D.; Notey, Jaspreet S.; Kelly, Robert M. (2010). "The genus Thermotoga: Recent developments". Environmental Technology. 31 (10): 1169–1181. doi:10.1080/09593330.2010.484076. PMC   3752655 . PMID   20718299.
  15. 1 2 Silva Comprehensive Ribosomal RNA Database (September 2015). "16S rRNA-based LTP release 123 (full tree)" (PDF). Archived from the original (PDF) on 2019-06-07. Retrieved 2019-06-07.
  16. ↑ Berman-Frank, Ilana; Lundgren, Pernilla; Falkowski, Paul (2003). "Nitrogen fixation and photosynthetic oxygen evolution in cyanobacteria". Research in Microbiology. 154 (3): 157–164. doi: 10.1016/s0923-2508(03)00029-9 . PMID   12706503.
  17. ↑ Hamilton, Trinity L.; Bryant, Donald A.; Macalady, Jennifer L. (2015-12-21). "The role of biology in planetary evolution: cyanobacterial primary production in low-oxygen Proterozoic oceans". Environmental Microbiology. 18 (2): 325–340. doi:10.1111/1462-2920.13118. PMC   5019231 . PMID   26549614.
  18. ↑ Tandeau de Marsac, Nicole; Houmard, Jean (January 1993). "Adaptation of cyanobacteria to environmental stimuli: new steps towards molecular mechanisms". FEMS Microbiology Letters. 104 (1–2): 119–189. doi: 10.1111/j.1574-6968.1993.tb05866.x .
  19. ↑ "Great Oxidation Event: More oxygen through multicellularity". ScienceDaily. Retrieved 2019-06-07.
  20. 1 2 "The bacteria that changed the world". evolution.berkeley.edu. May 2017. Retrieved 2019-06-07.

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