List I | List II | ||
---|---|---|---|
A | Mesozoic Era | I | Lower invertebrates |
B | Proterozoic Era | II | Fish & Amphibia |
C | Cenozoic Era | III | Birds & Reptiles |
D | Paleozoic Era | IV | Mammals |
An earthworm is a terrestrial invertebrate that is to the phylum Annelida. They display a tube-within-a-tube body plan; they are externally subdivided with corresponding internal subdivision, and they usually have setae on all divisions. They arise worldwide where soil, water, and temperature allow.
Generally, earthworms are found in soil, eating a wide variety of organic matter. This organic matter incorporates plant matter, rotifers, nematodes, bacteria, living protozoa, fungi, and other microorganisms. An earthworm's digestive system runs the expanse of its body. An earthworm respires throughout its skin. It has a double transport system made up of coelomic fluid that goes within the fluid-filled coelom and a simple, closed circulatory system.
It has a nervous system - “central and peripheral”. Its central nervous system comprises two ganglia above the mouth, one on either side, connected to a nerve running along its length to motor neurons and sensory cells in each segment. Large numbers of chemoreceptors concentrate close to its mouth.
Read More: Reproductive System of Earthworm