First universal common ancestorThe first universal common ancestor (FUCA) is proposed to have been a non-cellular entity that was the earliest organism with a genetic code capable of performing biological translation of RNA molecules to protein formation through peptide synthesis. Its descendants would include the last universal common ancestor (LUCA) and, therefore, all modern cells.Common descentCommon descent is a concept in evolutionary biology applicable when one species is the ancestor of two or more species later in time. According to modern evolutionary biology, all living beings could be descendants of a unique ancestor commonly referred to as the last universal common ancestor (LUCA) of all life on Earth. Common descent is an effect of speciation, in which multiple species derive from a single ancestral population.
ArchaeaArchaea ( ar-KEE-ə) is a domain of organisms. Traditionally, Archaea included only its prokaryotic members, but has since been found to be paraphyletic, as eukaryotes are known to have evolved from archaea. Even though the domain Archaea cladistically includes eukaryotes, the term archaea (sing. archaeon ar-KEE-on; from Ancient Greek ἀρχαῖον arkhaîon 'ancient') in English still generally refers specifically to prokaryotic members of Archaea.
Three-domain systemThe three-domain system is a taxonomicclassification system that groups all cellularlife into three domains, namely Archaea, Bacteria and Eukarya, introduced by Carl Woese, Otto Kandler and Mark Wheelis in 1990. The key difference from earlier classifications such as the two-empire system and the five-kingdom classification is the splitting of Archaea (previously named "archaebacteria") from Bacteria as completely different organisms.
Phylogenetic bracketingPhylogenetic bracketing is a method of inference used in biological sciences. It is used to infer the likelihood of unknown traits in organisms based on their position in a phylogenetic tree. One of the main applications of phylogenetic bracketing is on extinct organisms, known only from fossils, going back to the last universal common ancestor (LUCA).
BacteriaDomain of microorganismsSynonyms"Bacteria" (Cohn 1872) Cavalier-Smith 1983"Bacteria" Haeckel 1894"Bacteria" Cavalier-Smith 2002"Bacteriaceae" Cohn 1872a"Bacteriobionta" Möhn 1984"Bacteriophyta" Schussnig 1925"Eubacteria" Woese and Fox 1977"Neobacteria" Möhn 1984"Schizomycetaceae" de Toni and Trevisan 1889"Schizomycetes" Nägeli 1857Bacteria are ubiquitous, mostly free-living organisms often consisting of one biological cell.
VirusA virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. Since the first discovery of a virus, the tobacco mosaic virus, in the 1890s, more than 16,000 of the millions of virus species have been described in detail.
Cell (biology)The cell is the basic structural and functional unit of all forms of life or organisms. The term comes from the Latin word cellula meaning 'small room'. A biological cell basically consists of a semipermeable cell membrane enclosing cytoplasm that contains genetic material. Most cells are only visible under a microscope. Except for highly-differentiated cell types (examples include red blood cells and gametes) most cells are capable of replication, and protein synthesis.
Lipid bilayerThe lipid bilayer (or phospholipid bilayer) is a thin polar membrane made of two layers of lipid molecules. These membranes form a continuous barrier around all cells. The cell membranes of almost all organisms and many viruses are made of a lipid bilayer, as are the nuclear membrane surrounding the cell nucleus, and membranes of the membrane-bound organelles in the cell.
FossilA fossil (from Classical Latin fossilis, lit. 'obtained by digging') is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the fossil record.
Earliest known life formsEvidence of possibly the oldest forms of life on Earth has been found in hydrothermal ventprecipitates.(million years ago)The earliest known life forms on Earth may be as old as 4.1 billion years (or Ga) according to biologically fractionated graphite inside a single zircon grain in the Jack Hills range of Australia.
EukaryoteDomain of life whose cells have nucleiThe eukaryotes () are cellularorganisms of the domainEukaryota or Eukarya, which have a distinct cell nucleus (formed by a nuclear membrane), membrane-bound organelles and organization supported by a cytoskeleton. Extant eukaryotes are traditionally grouped into four kingdoms: animals, plants, fungi and protists.
lucaRelated word or term.
ArchaeaArchaea ( ar-KEE-ə) is a domain of organisms. Traditionally, Archaea included only its prokaryotic members, but has since been found to be paraphyletic, as eukaryotes are known to have evolved from archaea. Even though the domain Archaea cladistically includes eukaryotes, the term archaea (sing. archaeon ar-KEE-on; from Ancient Greek ἀρχαῖον arkhaîon 'ancient') in English still generally refers specifically to prokaryotic members of Archaea.Three-domain systemThe three-domain system is a taxonomicclassification system that groups all cellularlife into three domains, namely Archaea, Bacteria and Eukarya, introduced by Carl Woese, Otto Kandler and Mark Wheelis in 1990. The key difference from earlier classifications such as the two-empire system and the five-kingdom classification is the splitting of Archaea (previously named "archaebacteria") from Bacteria as completely different organisms.Phylogenetic bracketingPhylogenetic bracketing is a method of inference used in biological sciences. It is used to infer the likelihood of unknown traits in organisms based on their position in a phylogenetic tree. One of the main applications of phylogenetic bracketing is on extinct organisms, known only from fossils, going back to the last universal common ancestor (LUCA).BacteriaDomain of microorganismsSynonyms"Bacteria" (Cohn 1872) Cavalier-Smith 1983"Bacteria" Haeckel 1894"Bacteria" Cavalier-Smith 2002"Bacteriaceae" Cohn 1872a"Bacteriobionta" Möhn 1984"Bacteriophyta" Schussnig 1925"Eubacteria" Woese and Fox 1977"Neobacteria" Möhn 1984"Schizomycetaceae" de Toni and Trevisan 1889"Schizomycetes" Nägeli 1857Bacteria are ubiquitous, mostly free-living organisms often consisting of one biological cell.VirusA virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. Since the first discovery of a virus, the tobacco mosaic virus, in the 1890s, more than 16,000 of the millions of virus species have been described in detail.Cell (biology)The cell is the basic structural and functional unit of all forms of life or organisms. The term comes from the Latin word cellula meaning 'small room'. A biological cell basically consists of a semipermeable cell membrane enclosing cytoplasm that contains genetic material. Most cells are only visible under a microscope. Except for highly-differentiated cell types (examples include red blood cells and gametes) most cells are capable of replication, and protein synthesis.Lipid bilayerThe lipid bilayer (or phospholipid bilayer) is a thin polar membrane made of two layers of lipid molecules. These membranes form a continuous barrier around all cells. The cell membranes of almost all organisms and many viruses are made of a lipid bilayer, as are the nuclear membrane surrounding the cell nucleus, and membranes of the membrane-bound organelles in the cell.FossilA fossil (from Classical Latin fossilis, lit. 'obtained by digging') is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the fossil record.Earliest known life formsEvidence of possibly the oldest forms of life on Earth has been found in hydrothermal ventprecipitates.(million years ago)The earliest known life forms on Earth may be as old as 4.1 billion years (or Ga) according to biologically fractionated graphite inside a single zircon grain in the Jack Hills range of Australia.EukaryoteDomain of life whose cells have nucleiThe eukaryotes () are cellularorganisms of the domainEukaryota or Eukarya, which have a distinct cell nucleus (formed by a nuclear membrane), membrane-bound organelles and organization supported by a cytoskeleton. Extant eukaryotes are traditionally grouped into four kingdoms: animals, plants, fungi and protists.lucaRelated word or term.*As an Amazon Associate I earn from qualifying purchases.