Several such studies of ectothermic
species have shown that latitudinal and altitudinal variation in body size is based on genetic differences among populations; these species include the copepod crustacean Scottolana canadensis (Lonsdale and Levinton 1985); the honey bee, Apis mellifera (Alpatov 1929); the house fly, Musca domestica (Bryant 1977); the frog Rana sylvatica (Berven 1982), and several species of Drosophila (Stalker and Carson 1947, 1948; Prevosti 1955; David and Bocquet 1975; Louis et al.
And in the PALAIOS paper, the researchers suggest that even ectothermic
dinosaurs may have been able to live through the winters.
This argument is supported by the diverse array of ectothermic
organisms in which cell size increases at lower temperature (e.
Body temperature of ectothermic
organisms plays a fundamental role in a variety of physiological and behavioral processes, such as foraging behavior and use of habitat (Pianka, 1973), which have effects on survivorship, rate of growth, and reproductive success of lizards (Sinervo and Adolph, 1989).
The relationship between temperature and feeding is a well-known characteristic of ectothermic
animals, including crustaceans (Hartnoll, 1982), resulting from the direct impact of temperature on metabolic rate (Taylor 1981, Crear & Forteath 2000, Valverde et al.
Digestion in an ectothermic
herbivore, the green iguana (Iguana iguana): effect of food composition and body temperature.
1979; Payne 1984; Webster 1992), although evidence is also available for ectothermic
vertebrates (Shine 1979; Carothers 1984) and invertebrates (Ward 1988; Moore 1990).
(cold-blooded) animals lack the capacity to regulate their core body temperature outside of their preferred thermal niche.
This is in contrast to much of the previous work on thermotolerance in ectothermic
species, such as mussels and corals, which suggests that thermotolerance conferred upon initial exposure to deleterious temperatures allows organisms to tolerate or even acclimate to continued exposures (Buckley et al, 2001; Middlebrook et al, 2008) with a subsequent reduction in mortality rates compared to the initial event.
Locomotor performance is often used to study the thermal sensitivity of ectothermic
Our studies in tropical northern Australia have focussed on large ectothermic
predators (water pythons, Liasis fuscus) that fulfil all of these conditions.
However, for ectothermic
organisms, the thermal integral, or growing-degree-day (GDD), is a much better predictor of growth than is mean temperature (Neuheimer and Taggart, 2007) because it incorporates the variability in temperature, as well as the thermal history the organism experienced in the past.