Soil is a part of the biosphere usually full of life. Many of the living things that inhabit the interior of the ground are not visible to the naked eye, but there are others that can be easily seen.
An example is the worm. It lives in moist soil, as it is usually the fertile soil that serves as a flower bed (garden or garden).
THE worm belongs to the annelid phylum - name that includes worms with segmented body, divided into rings. The annelids comprise about 15,000 species, with representatives living in moist soil, freshwater and saltwater. They may be parasitic or free-living.
General characteristics of annelids
In addition to the earthworm, there are several species of annelids. We can name small animals - such as leech, which can measure only a few millimeters in length - and also large animals - such as the minhocuçu, which reaches two meters.
The habitat of annelids can be the water of the seas and oceans or freshwater and wetland. They are considered the most complex of worms. In addition to full digestive tract, have a system closed circulatory, that is, they have mouth and anus and also have a circulatory system in which blood only circulates within the vessels.
The body of the annelids is lined with thin, moist skin. This is an important feature of skin breathing - breathing through the skin, because the breathing gases do not pass through dry surfaces.
Most of the time, annelids are hermaphroditesthat is, each animal has two reproductive systems: the male and the female. However, they perform reciprocal and cross-fertilization, that is, two hermaphrodite animals cross and fertilize each other.