Selective Force

14,000,000 Leading Edge Experts on the ideXlab platform

Scan Science and Technology

Contact Leading Edge Experts & Companies

Scan Science and Technology

Contact Leading Edge Experts & Companies

The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform

George Chaplin - One of the best experts on this subject based on the ideXlab platform.

Mel Greaves - One of the best experts on this subject based on the ideXlab platform.

  • Response to Jablonski and Chaplin.
    Proceedings of The Royal Society B: Biological Sciences, 2014
    Co-Authors: Mel Greaves
    Abstract:

    The purpose of my paper [[1][1]] was to suggest that skin cancer, and particularly squamous cell carcinoma (SCC), is a plausible candidate Selective Force in the evolution of black pigmentation in early humans. The argument was advanced in part to counter the cursory dismissal of cancer as a

  • was skin cancer a Selective Force for black pigmentation in early hominin evolution
    Proceedings of The Royal Society B: Biological Sciences, 2014
    Co-Authors: Mel Greaves
    Abstract:

    Melanin provides a crucial filter for solar UV radiation and its genetically determined variation influences both skin pigmentation and risk of cancer. Genetic evidence suggests that the acquisition of a highly stable melanocortin 1 receptor allele promoting black pigmentation arose around the time of savannah colonization by hominins at some 1–2 Ma. The adaptive significance of dark skin is generally believed to be protection from UV damage but the pathologies that might have had a deleterious impact on survival and/or reproductive fitness, though much debated, are uncertain. Here, I suggest that data on age-associated cancer incidence and lethality in albinos living at low latitudes in both Africa and Central America support the contention that skin cancer could have provided a potent Selective Force for the emergence of black skin in early hominins.

Paul J Hearty - One of the best experts on this subject based on the ideXlab platform.

  • Bermuda land snails in Quaternary Poecilozonites of gigantism in Predation as the primary Selective Force in recurrent evolution
    2020
    Co-Authors: Storrs L Olson, Paul J Hearty
    Abstract:

    During the last half million years, pulses ofgigantism in the anagenetic lineage of landsnails of the subgenus Poecilozonites on Bermudawere correlated with glacial periods when lowersea level resulted in an island nearly an order ofmagnitude larger than at present. During thoseperiods, the island was colonized by large ver-tebrate predators that created selection pressurefor large size and rapid growth in the snails.Extreme reduction in land area from risingseas, along with changes in ecological conditionsat the onset of interglacial episodes, markedextinction events for large predators, afterwhich snails reverted to much smaller size. Thegiant snails were identical in morphologyduring the last two glacials when the predatorsincluded a large flightless rail Rallus recessus(marine isotope stages (MIS) 4-2) and a craneGrus latipes and a duck Anas pachysceles(MIS 6). In a preceding glacial period (MIS 10),when the fauna also included the tortoise Hesper-otestudo bermudae, the snails were not onlylarge, but the shells were much thicker, presum-ably to prevent crushing by tortoises. Evolutionof Poecilozonites provides an outstandingexample of dramatic morphological change inresponse to environmental pressures in theabsence of cladogenesis.Keywords: anagenesis; biogeography; extinction;Hesperotestudo; island area; sea-level cycles1. INTRODUCTIONOn the isolated North Atlantic island of Bermuda,1000 km east–southeast of North Carolina, USA,land snails of the family Zonitidae, genus and subge-nus Poecilozonites, evolved a remarkable diversity ofshell sizes and shapes during the Pleistocene thatGould (1969, p. 407) considered to be an example of‘an adaptive radiation comparable in scope with theclassic insular speciation and ecologic differentiationof Darwin’s finches’. With much more extensive col-lecting and refinement of stratigraphy and chronology(Hearty et al. 2004; Hearty & Olson in press), weestablished that this supposed radiation consists of asingle anagenetic series with highly divergent shellmorphologies that do not overlap in time (Hearty &Olson in press).Changes in shell morphology in Poecilozonites arecorrelated with drastic changes in island area andenvironmental conditions caused by eustatic sea-levelchanges during the Pleistocene. During glacial periods,sea levels fall below the level of the Bermuda platformcreating a large island with an area of .650 km

  • predation as the primary Selective Force in recurrent evolution of gigantism in poecilozonites land snails in quaternary bermuda
    Biology Letters, 2010
    Co-Authors: Storrs L Olson, Paul J Hearty
    Abstract:

    During the last half million years, pulses of gigantism in the anagenetic lineage of land snails of the subgenus Poecilozonites on Bermuda were correlated with glacial periods when lower sea level resulted in an island nearly an order of magnitude larger than at present. During those periods, the island was colonized by large vertebrate predators that created selection pressure for large size and rapid growth in the snails. Extreme reduction in land area from rising seas, along with changes in ecological conditions at the onset of interglacial episodes, marked extinction events for large predators, after which snails reverted to much smaller size. The giant snails were identical in morphology during the last two glacials when the predators included a large flightless rail Rallus recessus (marine isotope stages (MIS) 4-2) and a crane Grus latipes and a duck Anas pachysceles (MIS 6). In a preceding glacial period (MIS 10), when the fauna also included the tortoise Hesperotestudo bermudae, the snails were not only large, but the shells were much thicker, presumably to prevent crushing by tortoises. Evolution of Poecilozonites provides an outstanding example of dramatic morphological change in response to environmental pressures in the absence of cladogenesis.

Nina G Jablonski - One of the best experts on this subject based on the ideXlab platform.

Beata Ujvari - One of the best experts on this subject based on the ideXlab platform.

  • oncogenesis as a Selective Force adaptive evolution in the face of a transmissible cancer
    BioEssays, 2018
    Co-Authors: Tracey Russell, Thomas Madsen, Frederic Thomas, Nynke Raven, Rodrigo Hamede, Beata Ujvari
    Abstract:

    Similar to parasites, malignant cells exploit the host for energy, resources and protection, thereby impairing host health and fitness. Although cancer is widespread in the animal kingdom, its impact on life history traits and strategies have rarely been documented. Devil facial tumour disease (DFTD), a transmissible cancer, afflicting Tasmanian devils (Sarcophilus harrisii), provides an ideal model system to monitor the impact of cancer on host life-history, and to elucidate the evolutionary arms-race between malignant cells and their hosts. Here we provide an overview of parasite-induced host life history (LH) adaptations, then both phenotypic plasticity of LH responses and changes in allele frequencies that affect LH traits of Tasmanian devils in response to DFTD are discussed. We conclude that akin to parasites, cancer can directly and indirectly affect devil LH traits and trigger host evolutionary responses. Consequently, it is important to consider oncogenic processes as a Selective Force in wildlife.