Evolution of bacteria

{{Life timeline}}

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{{Cite book|last1=Hartman|first1=H|last2=Matsuno|first2=K|title=The Origin and Evolution of the Cell|date=1993|publisher=World Scientific|pages=1–446|doi=10.1142/9789814536219|isbn=9789810212629}} 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|date=May 2021}}

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|date=May 2021}}

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.{{Cite web|url=http://www.nas.edu/evolution/index.html|title=Evolution Resources from the National Academies|website=www.nas.edu|access-date=2019-05-21|archive-date=2016-06-03|archive-url=https://web.archive.org/web/20160603230514/http://www.nas.edu/evolution/index.html|url-status=dead}} 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,{{Cite web|url=https://microbiologyonline.org/about-microbiology/introducing-microbes/bacteria|title=About Microbiology – Bacteria|website=microbiologyonline.org|language=en|access-date=2019-05-21|archive-date=2019-11-27|archive-url=https://web.archive.org/web/20191127003526/https://microbiologyonline.org/about-microbiology/introducing-microbes/bacteria|url-status=dead}} which allows for fast adaptation, meaning new strains of bacteria can evolve quickly. This has become an issue regarding antibiotic resistant bacteria.{{Citation needed|date=May 2021}}

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

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 bacteria has been discovered in the Australian Apex Chert near ancient hydrothermal vents.{{Cite book|title=Geology and putative microfossil assemblage of the c. 3460 Ma 'Apex Chert', Chinaman Creek, Western Australia : a field and petrographic guide|last=Brasier, M. D.|date=2011|publisher=Geological Survey of Western Australia|isbn=9781741683660|oclc=748237320}}{{Cite web|url=https://www.researchgate.net/publication/259529218|title=Apex Chert Microfossils|website=ResearchGate|language=en|access-date=2019-05-21}} These rocks date back 3.46 billion years and, because oxygen was not present in large quantities in Earth's early atmosphere, these fossils are thought to represent early thermophilic bacteria, which do not require oxygen to survive.{{Cite journal|last1=Frock|first1=Andrew D.|last2=Notey|first2=Jaspreet S.|last3=Kelly|first3=Robert M.|date=2010|title=The genus Thermotoga: Recent developments|journal=Environmental Technology|volume=31|issue=10|pages=1169–1181|doi=10.1080/09593330.2010.484076|pmc=3752655|pmid=20718299}} Furthermore, living species such as Thermotoga neapolitana, which are thought to resemble their ancestral form, live around these vents, which some scientists have used as evidence to support this theory.{{Citation needed|date=May 2021}}

More recent evidence 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. 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. 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|date=May 2021}}

{{see also|Bacterial taxonomy}}

File:Colourful Thermophilic Archaebacteria Stain in Midway Geyser Basin.jpg, distinct from Thermotogales.]]

The phylogeny based on the work of the All-Species Living Tree Project.{{Cite web|url=http://www.arb-silva.de/fileadmin/silva_databases/living_tree/LTP_release_123/LTPs123_SSU_tree.pdf|title=16S rRNA-based LTP release 123 (full tree)|last=Silva Comprehensive Ribosomal RNA Database|date=September 2015|access-date=2019-06-07|archive-date=2019-06-07|archive-url=https://web.archive.org/web/20190607122718/https://www.arb-silva.de/fileadmin/silva_databases/living_tree/LTP_release_123/LTPs123_SSU_tree.pdf|url-status=dead}}

{{clade|{{clade

|label1=Thermotogaceae

|1={{clade

|label1=Thermotoga

|1={{clade

|1=T. naphthophila

|2={{clade

|1=T. petrophila

|2={{clade

|1= T. maritima (type sp.)

|2= T. neapolitana

}}

}}

}}

|label2=Pseudothermotoga

|2={{clade

|1={{clade

|1= P. hypogea

|2= P. thermarum

}}

|2={{clade

|1= P. subterranea

|2={{clade

|1= P. elfii

|2= P. lettingae

}}

}}

}}

}}

|label2=Fervidobacteriaceae

|2={{clade

|label1=Fervidobacterium

|1={{clade

|1={{clade

|1=F. changbaicum

|2=F. islandicum

}}

|2={{clade

|1=F. nodosum (type sp.)

|4={{clade

|1=F. gondwanense

|2=F. riparium

}}

}}

}}

|label2=Thermosipho

|2={{clade

|1=T. activus

|2={{clade

|1=T. geolei

|2={{clade

|1= T. atlanticus

|2={{clade

|1={{clade

|1=T. affectus

|2=T. melanesiensis

}}

|2={{clade

|1=T. globiformans

|2={{clade

|1=T. africanus (type sp.)

|2=T. japonicus

}}

}}

}}

}}

}}

}}

}}

}}||label1=Thermotogales}}

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.{{Cite journal|last1=Berman-Frank|first1=Ilana|last2=Lundgren|first2=Pernilla|last3=Falkowski|first3=Paul|date=2003|title=Nitrogen fixation and photosynthetic oxygen evolution in cyanobacteria|journal=Research in Microbiology|volume=154|issue=3|pages=157–164|doi=10.1016/s0923-2508(03)00029-9|pmid=12706503|doi-access=free}} This prokaryote produces oxygen as a byproduct of its photosynthetic processes.{{Cite journal|last1=Hamilton|first1=Trinity L.|last2=Bryant|first2=Donald A.|last3=Macalady|first3=Jennifer L.|date=2015-12-21|title=The role of biology in planetary evolution: cyanobacterial primary production in low-oxygen Proterozoic oceans|journal=Environmental Microbiology|volume=18|issue=2|pages=325–340|doi=10.1111/1462-2920.13118|pmid=26549614|pmc=5019231}} 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|date=May 2021}}

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.{{Cite journal|last1=Tandeau de Marsac|first1=Nicole|last2=Houmard|first2=Jean|date=January 1993|title=Adaptation of cyanobacteria to environmental stimuli: new steps towards molecular mechanisms|journal=FEMS Microbiology Letters|volume=104|issue=1–2|pages=119–189|doi=10.1111/j.1574-6968.1993.tb05866.x|doi-access=free}} Due to this trait some scientist credit this phylum to causing the Great Oxygenation Event roughly 2.3 billion years ago{{Cite web|url=https://www.sciencedaily.com/releases/2013/01/130117084856.htm|title=Great Oxidation Event: More oxygen through multicellularity|website=ScienceDaily|language=en|access-date=2019-06-07}}

File:Cyanobacteria Aggregation2.jpg

However, the closest known relatives of oxygen producing Cyanobacteria did not produce oxygen.{{Cite web|url=https://evolution.berkeley.edu/evolibrary/news/170503_cyanobacteria|title=The bacteria that changed the world|website=evolution.berkeley.edu|date=May 2017 |access-date=2019-06-07}} 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. This suggests that Cyanobacteria, Melainabacteria, and Sericytochromatia evolved from a non-photosynthetic common ancestor.{{Citation needed|date=May 2021}}

{{reflist}}

• {{cite journal |vauthors=Gabrić P |title=Impact of Infectious Disease on Humans and Our Origins |journal=Anthropological Review |volume=85 |issue=1 |pages=101–106 |year=2022 |pmid= |doi=10.18778/1898-6773.85.1.07 |url=https://czasopisma.uni.lodz.pl/ar/article/view/12927 |access-date=2023-05-11 |hdl=11089/43149 |hdl-access=free }}

• [http://www.thebigger.com/biology/monera/what-are-cyanobacteria-and-what-are-its-types/ What are Cyanobacteria and What are its Types?]
• [http://www-cyanosite.bio.purdue.edu/ Webserver for Cyanobacteria Research]
• {{cite web|url=http://www.rationalrevolution.net/articles/understanding_evolution.htm|title=Understanding Evolution: History, Theory, Evidence, and Implications|last=Price|first=R. G.|website=rationalrevolution.net|access-date=2015-02-23}}

{{Evolution}}

{{Bacteria}}

{{Bacteria classification}}

Category:Evolutionary biology