Search results
Results from the WOW.Com Content Network
In evolutionary biology, the term cellularization (cellularisation) has been used in theories to explain the evolution of cells, for instance in the pre-cell theory, [1] [2] [3] dealing with the evolution of the first cells on this planet, and in the syncytial theory [4] attempting to explain the origin of Metazoa from unicellular organisms.
Eukaryogenesis, the process which created the eukaryotic cell and lineage, is a milestone in the evolution of life, since eukaryotes include all complex cells and almost all multicellular organisms. The process is widely agreed to have involved symbiogenesis , in which an archeon and a bacterium came together to create the first eukaryotic ...
Obcells are hypothetical proto-organisms or the earliest form of life. The term was first proposed by Thomas Cavalier-Smith in 2001. According to Cavalier-Smith's theory for the origin of the first cell, two cup-shaped obcells or hemicells fused to make a protocell with double-lipid layer envelope, internal genome and ribosomes, protocytosol, and periplasm.
Lineage (evolution) – Sequence of populations, organisms, cells, or genes that form a line of descent; Molecular phylogenetics – Branch of phylogeny that analyzes genetic, hereditary molecular differences; Most recent common ancestor – Most recent individual from which all organisms in a group are directly descended
In any case, the problem lay buried in the catch-all rubric "origin of life"--where, because it is a biological not a (bio)chemical problem, it was effectively ignored. Scientific interest in cellular evolution started to pick up once the universal phylogenetic tree, the framework within which the problem had to be addressed, was determined.
His formal test favoured the existence of a universal common ancestry over a wide class of alternative hypotheses that included horizontal gene transfer. Basic biochemical principles imply that all organisms do have a common ancestry. [71] A proposed, earlier, non-cellular ancestor to LUCA is the First universal common ancestor (FUCA).
Convergent evolution is the process in which related or distantly related organisms evolve similar characteristics independently. This type of evolution creates analogous structures which have a similar function, structure, or form between the two species. For example, sharks and dolphins look alike but they are not related.
Evolutionary biology, in particular the understanding of how organisms evolve through natural selection, is an area of science with many practical applications. [1] [2] Creationists often claim that the theory of evolution lacks any practical applications; however, this claim has been refuted by scientists.