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In biology and botany, indeterminate growth is growth that is not terminated, in contrast to determinate growth that stops once a genetically predetermined structure has completely formed. Thus, a plant that grows and produces flowers and fruit until killed by frost or some other external factor is called indeterminate.
Modular organisms [3] have indeterminate growth forms (life stages not set) through repeated iteration of genetically identical modules (or individuals), and it can be difficult to distinguish between the colony as a whole and the modules within. [4] In the latter case, modules may have specific functions within the colony.
Despeciation – Loss of a species of animal due to its combining with another species; Anagenesis – Gradual evolutionary change in a species without splitting; Extinction – Termination of a taxon by the death of its last member; Microevolution – Change in allele frequencies that occurs over time within a population
Growth mostly occurs through cell proliferation but also through changes in cell size or the deposition of extracellular materials. The development of plants involves similar processes to that of animals. However, plant cells are mostly immotile so morphogenesis is achieved by differential growth, without cell movements.
The evolution of biological complexity is one important outcome of the process of evolution. [1] Evolution has produced some remarkably complex organisms – although the actual level of complexity is very hard to define or measure accurately in biology, with properties such as gene content, the number of cell types or morphology all proposed as possible metrics.
It harbors two pools of stem cells around an organizing center called the quiescent center (QC) cells and together produces most of the cells in an adult root. [21] [22] At its apex, the root meristem is covered by the root cap, which protects and guides its growth trajectory. Cells are continuously sloughed off the outer surface of the root ...
The embryo forms a disc of cells, called a blasto-disc, on top of the yolk. Discoidal cleavage is commonly found in monotremes, birds, reptiles, and fish that have telolecithal egg cells (egg cells with the yolk concentrated at one end). The layer of cells that have incompletely divided and are in contact with the yolk are called the "syncytial ...
A relationship between mean cell number and cell number variation was established following a law possessing an exponent of 2 upon a variety of multicellular eutelic taxa. [7] Hydatina senta (Phylum Rotifera, Order Bdelloidea) is a species of rotifers which demonstrate the most complete cell constancy of any species studied before 1912. [8]