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Title: What is the evolutionary status of dicots and monocots Post by: Qayoom Hakim on Jul 31, 2019 Qayoom
Biology teacher India Title: Re: What is the evolutionary status of dicots and monocots Post by: loeinjhonson on Aug 1, 2019 Are you asking if modern-dat monocots evolved from dicots? But if they did, there are many other differences between the two groups, the cotyledon number just happens to be the one that humans arbitrarily chose to use for classification purposes. The change from 2 to 1 could easily have been a completely neutral random change, with some of the other differences driving the divergence in terms of positive selection factors.
The fact that monocots and dicots frequently live side by side without one outcompeting and displacing the other in the environment would suggest that neither side has that significant a competitive advantage in typical environmental conditions. And if monocots did not evolve from dicots, but rather both diverging from a common ancestor, there again need not be any specific advantage for the number of cotyledons, beyond the possible advantage of having some number of cotyledons versus having none. The two groups may have diverged from a common ancestor that had variable numbers of cotyledons, with all numbers being neutral variants, which each lineage later evolving their unique fixed number via genetic drift. |