239
en
Qj
Qj
E
Plough mark. (Reimnitz et al. 1973)
poikilotherm
meters
Pogonophora (beard worms) phylum of long slender marine worms, which live
in thread-like chitinous tubes with a characteristic banding pattern. The
head has one to many tentacles, and setae are only found at the caudal body
part. The infaunal animals live in soft sediment at depths between 100 and
4000 m. They feed by absorbing organic nutrients with their tentacles. The
Vestimentifera form a special group within this phylum.
poikilotherm (cold-blooded animal) organism that is not able to stabilize its body
temperature. In these organisms the heat produced by metabolic activity is
lost to the environment. As the body temperature closely follows the changes
in the environmental temperature, the activity of these animals is also highly variable. At low temperature the animals may become very sluggish. All
living organisms, with the exception of most mammals and birds, are poikilothermic. On land some poikilothermic species become to a certain degree
homeothermic (warm-blooded) by habitat selection. On the other hand
some homeothermic animals may (temporarily) lose their homeothermic
capabilities during inactive periods (e.g., during hibernation).