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Ellison Abstract- 1991 Ellison and Vam Vikites

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Ellison, A. M., and D. Vam Vikites. 1991. Evolutionarily stable morphologies in pea populations. Evolution 45: 40-48.


We investigated the hypothesis that plant form can dramatically affect plant competitive ability, and that forms with dense canopies can invade populations of plants with more open canopies regardless of initial relative frequencies. Under controlled field conditions, we examined the effects of plant form on growth rate, size variation, mortality, and reproduction in high-density monocultures and mixtures of two morphologically distinct varieties of peas. These two varieties differ genetically at only the afila locus. In high-density monocultures and mixtures, peas with finely dissected, minute leaflets (af/af) grew more slowly and produced fewer seeds than Af/-individuals with large leaflets that cast more shade on neighbors. After as few as four generations, mixtures begun with 10% Af/- peas would be expected to evolve to Af/- monocultures. We conclude that an increase in morphological complexity (e.g., virtually leafless to leafy) can have dramatic ecological and evolutionary impacts on plant population dynamics.

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