Predation risk and the cost of being fat
Article Abstract:
A study conducted on the changes in body mass of great tits in Wytham, UK, demonstrates a relation between the amount of fat stored by the tits and predation risk. Before the 1950s the number of its principal predator, the sparrowhawk Accipiter ninus, changed significantly. In between 1960s and 1970s, when the sparrowhawk was absent, the tits weighed more. Low body mass increases the chances of starvation in winters while a high body mass decreases the ability to escape predators. The difference in body mass is an adaptation of the tits to the risk of starvation and predation.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1995
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In the pink (and yellow)
Article Abstract:
Land snails of the species Cepaea hortensis living in south-eastern England show environmentally-induced morphological changes that are due to the influence of natural selection on genetics. Researcher Robert Cameron studied snail populations 25 years ago to determine the frequency of pink and yellow shells; yellow-shelled snails survive better in the cooler temperatures of valley bottoms than do pink-shelled snails. Cameron studied the same populations recently and reports evidence of gene-frequency changes attributable to natural selection.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1992
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Theory fits the bill in the Galapagos Islands
Article Abstract:
A study of the evolution of Geospiza fortis and G. scandens, two finches of the Galapagos Islands, is presented. The study involved the quantitative prediction of selection for bill size based on measurements of selective forces such as diet availability and estimates of the heritability of the trait. The quantitative prediction for bill size exhibited a remarkably close fit, indicating that it is possible to make quantitative predictions of for natural selection.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1993
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