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Plant evolution is the subset of evolutionary phenomena that concern plants. Evolutionary phenomena are characteristics of populations that are described by averages, medians, distributions, and other statistical methods. This distinguishes plant evolution from plant development, a branch of developmental biology which concerns the changes that ...
if the allele A frequency is denoted by the symbol p and the allele a frequency denoted by q, then p+q=1. For example, if p =0.7, then q must be 0.3. In other words, if the allele frequency of A equals 70%, the remaining 30% of the alleles must be a , because together they equal 100%.
Land plants evolved from a group of freshwater green algae, perhaps as early as 850 mya, [3] but algae-like plants might have evolved as early as 1 billion years ago. [2] The closest living relatives of land plants are the charophytes, specifically Charales; if modern Charales are similar to the distant ancestors they share with land plants, this means that the land plants evolved from a ...
The idea of a tree of life arose from ancient notions of a ladder-like progression from lower into higher forms of life (such as in the Great Chain of Being).Early representations of "branching" phylogenetic trees include a "paleontological chart" showing the geological relationships among plants and animals in the book Elementary Geology, by Edward Hitchcock (first edition: 1840).
The duplicated genes may attain new function, either by changes in expression pattern or changes in activity. Polyploidy and gene duplication are believed to be among the most powerful forces in evolution of plant form. It is not known though, why genome doubling is such a frequent process in plants.
Caytoniaceous seed ferns were another group of important plants during this time and are thought to have been shrub to small-tree sized. [16] Ginkgo-like plants were particularly common in the mid- to high northern latitudes. In the Southern Hemisphere, podocarps were especially successful, while Ginkgos and Czekanowskiales were rare. [15] [17]
The rate of evolution is quantified as the speed of genetic or morphological change in a lineage over a period of time. The speed at which a molecular entity (such as a protein, gene, etc.) evolves is of considerable interest in evolutionary biology since determining the evolutionary rate is the first step in characterizing its evolution . [ 1 ]
It is important to note the impact that humans have on genetic diversity as well, and be aware of the ways to reduce harmful impacts on natural environments. [26] Major roads, waterway pollution, and urbanization all cause environmental selection and could potentially result in changes in allele frequencies. [ 27 ]