"Biologists often distinguish 'convergent' from 'parallel' evolution. T he following paragraph is from an article by Jeff Arendt and David Reznick in Trends in Ecology and Evolution Vol. Why Differentiate Parallel From Convergent Evolution? This latter conclusion supports the independent (parallel) evolution of vessels in the Gnetophyta. The current consensus among authorities (as of 2010) is that Amborella trichopoda (a primitive angiosperm without vessels) and all other flowering plants represent sister clades derived from an common ancester without vessels. Some older references have suggested that the Gnetophyta may represent a "missing link" in the evolution of flowering plants, but others say that vessels and double fertilization are examples of parallel evolution, and the Gnetophyta are more closely related to conifers than angiosperms. Double fertilization was once thought to be a strictly angiosperm characteristic. In addition, species of Ephedra have double fertilization, where two sperm are involved in the fertilization process. Photosynthetic pathways, such as CAM (crassulacean acid metabolism) and C-4 photosynthesis, have also evolved independently in distantly-related plant families.Ī nother example of parallel evolution is the appearance of xylem vessels in the vascular tissues of very distantly-related plants, such as Ephedra in the gymnospermous division Gnetophyta and flowering plants in the angiospermous division Anthophyta (Magnoliophyta). Some plants have evolved independently into a mycotrophic mode of existence where they obtain nutrients from mycorrhizal soil fungi, which in turn, are parasitic on the roots of nearby forest trees and shrubs. There are many examples of parallel evolution in plants, including distantly-related plant families that have evolved from an autotrophic to a parasitic mode of existence. This phenomenon is called parallel evolution. It culminates in unrelated organisms with similar morphological characteristics even though they did not have a common ancestor. S ometimes evolutionary change follows a common pathway in two or more unrelated or distantly-related organisms because of similar environmental pressures. Which of these insects is a preying mantis and which is a mantispid? (I prefer "preying" rather than "praying" because I don't think these insects are that religious.)Ī small mantispid and a preying mantis, an example of convergent evolution. Similar Terms That Are Difficult To Distinguish
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