Ammonites have become confused with fossil snails. Ammonites however, belong to an extinct group of

Snails or gastropods (Gastropoda) are a class of the tribe of molluscs (Mollusca). The name gastropods and scientific names are due to the muscular bogen 3021 tripod bottom of the elongated body, which allows for the movement: gaster means abdomen or stomach, bogen 3021 tripod and poda means legs. Worldwide, there are approximately 60,000 to 75,000 bogen 3021 tripod different species.
Snails are the only molluscs also live on land. Most snails marine life and also live a part of the species in the freshwater. The snails can be divided in different ways, so there are snails with a cottage (snails) and slugs (nudibranchs) species by gills and others who breathe through lungs, there are scavengers, herbivores, detritus eaters, and even prey hunting carnivores. The first recognizable snails stems from the Cambrian. Snails are characterized by a single shell, which usually has windings. Most snails are hermaphrodites, they can be separated by gender, but also hermaphrodite. Snails are eaten by many animals, including humans.
Because snails often have a calcified house, there are many of this group of animals extinct species known. Many species are used as a guide fossil, so that the age of the strata can be determined.
The body of a snail consists of a very large proportion of water, the slimy skin causes in land-dwelling snails that animals bogen 3021 tripod do not dry out. However, the main function of mucus is in the propellant. It provides, as it were for the road to be paved, through which the animal itself to slide easily capable of moving over the substrate. If a snail should move vertically, which requires a better grip than move horizontally, a different kind of mucus is secreted. Besides the moisture snails are also very sensitive to other environmental factors such as temperature, light intensity and especially salinity because of this very significant impact on the water balance of their watery body.
Land-dwelling species seek places where the relative humidity is high. Therefore many species live hidden in the vegetation, among fallen leaves or dead wood, under rocks, in crevices, etc. Most species avoid the sun although some have adapted to living in a dry and hot environment. bogen 3021 tripod Many species are mostly or even only active at night or emerge after rain.
Most snails have an unobtrusive appearance to attract no enemies. The houses of many sea snails do have a beautiful shell, but this is not seen in living animals because of the periostracum of the shell. Nudibranchs have often just bright colors to indicate that they are poisonous. Many species have spectacular colors and patterns, and therefore are popular in saltwater aquariums. Of dead animals they keep in a preservative liquid colors are not preserved.
The snails evolved in the sea, the earliest known species are from the late Cambrian. Some snail-like fossils as Helcionella and Scenella from the Early Cambrian nowadays no longer be regarded as snails. In the early Cambrian living creature Aldanella had a twisted shell but was probably not a mollusk. In the Ordovician, there were already several types of snails in various bogen 3021 tripod types of waters. Species from the Paleozoic among the more primitive molluscs, although some still exist. During the Carboniferous had the snails all the shapes and sizes of the species we know today but that is only based on the likeness of the shell. The ancestors of most modern snails came to pass in the Mesozoic. The first land-dwelling snail is Maturipupa and shows up in the Carboniferous in Europe. The land-dwelling snails bogen 3021 tripod were however sparse until the Cretaceous, which includes the famous Helix species strains. bogen 3021 tripod
In outcrops from the Mesozoic and Cenozoic get slightly more than other fossils of mollusks fossils. This is due to the hard shells of snails (and bivalves) that can be properly preserved. They are found in all kinds of deposits, as the sediment but is not descaled. Shells bogen 3021 tripod of snail species are also prints in soft sediment originally found as a fossil. The geological study of fossil snails and mollusks in general gives a picture of the environmental changes in the past.
Ammonites have become confused with fossil snails. Ammonites however, belong to an extinct group of squid or cephalopods, another mollusk group. Like snails these animals had a single, spiral shell. However, the animals possessed, as is the current cuttlefish, multiple tentacle-like arms.
1 = 2 shell hepatopancreas = 3 = 4 = a lung