Behavioral Response of Embryos to Environmental Variation in Oviparous Vertebrates

Development of the pulmonary surfactant system in two oviparous vertebrates.

In birds and oviparous reptiles, hatching is often a lengthy and exhausting process, which commences with pipping followed by lung clearance and pulmonary ventilation. We examined the composition of pulmonary surfactant in the developing lungs of the chicken, Gallus gallus, and of the bearded dragon, Pogona vitticeps. Lung tissue was collected from chicken embryos at days 14, 16, 18 (prepipped)...

Calcium metabolism in embryos of the oviparous snake Coluber constrictor.

Total calcium in embryos of an oviparous, colubrid snake (Coluber constrictor L.) rises rapidly during the last half of incubation as the embryos increase in size. Although most of this calcium is drawn from stores in the yolk, hatchlings contain more calcium than was present in yolk of eggs at oviposition. Because shells from eggs incubated to hatching contain less calcium than do shells from ...

Variation in the response of barley cultivars to nirrogen fertilizer

The Partition of Calcium and Protein in the Blood of Oviparous Vertebrates during Estrus

Six classes of vertebrate animals were injected with massive doses of estrogen for various periods of time necessary to produce a grossly recognizable response. Swelling of the liver, associated with hypercalcemia, hyperproteinemia, and lipemia, occurred in Teleostei, Amphibia, Reptilia, and Aves, but not in Elasmobranchii or Mammalia. Calcium that was added to the serum was bound as a calcium ...

Calcium provision to oviparous and viviparous embryos of the reproductively bimodal lizard Lacerta (Zootoca) vivipara.

Embryos of oviparous squamate reptiles typically obtain calcium from both yolk and eggshell but differ from other oviparous amniotes (turtles, birds and crocodilians) because they are heavily dependent on calcium-rich yolk. Eggs of viviparous squamates lack calcareous eggshells, and embryos receive calcium solely from yolk or from both yolk and placenta. The pattern of calcium mobilization by a...