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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.
Cyanobacteria are ubiquitous in marine environments and play important roles as primary producers. They are part of the marine phytoplankton, which currently contributes almost half of the Earth's total primary production. [ 33 ] About 25% of the global marine primary production is contributed by cyanobacteria.
As for life on land, in 2019 scientists reported the discovery of a fossilized fungus, named Ourasphaira giraldae, in the Canadian Arctic, that may have grown on land a billion years ago, well before plants are thought to have been living on land. [99] [100] [101] The earliest life on land may have been bacteria 3.22 billion years ago. [102]
Symbiogenesis (endosymbiotic theory, or serial endosymbiotic theory[2]) is the leading evolutionary theory of the origin of eukaryotic cells from prokaryotic organisms. [3] The theory holds that mitochondria, plastids such as chloroplasts, and possibly other organelles of eukaryotic cells are descended from formerly free-living prokaryotes ...
The history of life on Earth traces the processes by which living and extinct organisms evolved, from the earliest emergence of life to the present day. Earth formed about 4.5 billion years ago (abbreviated as Ga, for gigaannum) and evidence suggests that life emerged prior to 3.7 Ga. [1] [2] [3] The similarities among all known present-day species indicate that they have diverged through the ...
By 1.75 Ga, thylakoid-bearing cyanobacteria had evolved, as evidenced by fossils from the McDermott Formation of Australia. [11] Many crown node eukaryotes (from which the modern-day eukaryotic lineages would have arisen) have been approximately dated to around the time of the Paleoproterozoic Era.
Although the term bacteria traditionally included all prokaryotes, the scientific classification changed after the discovery in the 1990s that prokaryotes consist of two very different groups of organisms that evolved from an ancient common ancestor. These evolutionary domains are called Bacteria and Archaea.
Cyanobacterial morphology refers to the form or shape of cyanobacteria. Cyanobacteria are a large and diverse phylum of bacteria defined by their unique combination of pigments and their ability to perform oxygenic photosynthesis. [2][3] Cyanobacteria often live in colonial aggregates that can take a multitude of forms. [3]