| albumin:
A fluid filled with water-soluble proteins. |
| aestivation:
A period of inactivity, or dormancy, induced by unfavorable
conditions. During aestivation, the earthworm curls up into a knot
and becomes quite pink. |
| anecic:
A habitat classification term. These earthworms live in deep vertical
burrows, but feed at or near the soil surface, especially at night. |
| annelid:
An organism that has a segmented body, giving it a ringed
appearance. The segments are arranged one beside each other symmetrically
along the length of the earthworm to form the body. |
| anus:
See periproct |
| calcareous:
Something that is made of or contains calcium carbonate;
in soil, can occur as chalk or limestone. |
| castings:
Earthworm feces; the voided earth and other waste materials
that are deposited on the surface of the ground. Not all species form
their casts above ground. |
| circular
muscles: See muscles |
| clitellate
adult: Any earthworm with a developed clitellum and genital
markings. |
| clitellum:
(see Earthworm Anatomy) A swelling in the skin near the head that secretes material
to form cocoons. The clitellum forms a band that can be flared, non-flared,
saddle shaped, or annular. The clitellum is generally found between
segments 26-33. |
| cocoon:
A sac that contains the earthworm’s eggs. The cocoon
is formed at the clitellum, and then travels from the clitellum to
the head. Here it slides off the earthworm’s body and is deposited
into the soil. |
| coelom:
The cavity between the body wall and the food (alimentary)
canal. |
| crop:
A widened portion of the digestive system that lacks the muscularity
of the gizzard. It is located after the esophagus, but before the
gizzard. An area where food is digested. |
| dorsal
pores: The small holes located in the intersegmental furrows
down the middle of the earthworm’s back. These holes lead to
the coelomic cavity. The term first dorsal pore 5/6 means that
this is the first dorsal pore and it is located between segments 5
and 6. |
| endogeic:
A habitat classification term. These earthworms burrow
continuously to form a network of channels – some vertical and
some horizontal in the rhizosphere. The majority of the burrows are
horizontal. |
| epidermis:
Skin; the outer cellular layer of the body wall, which
secretes mucus. |
| epigeic:
A habitat classification term. These earthworms are not
strong burrowers, and live in the uppermost layers of the soil or
litter layer (i.e. decaying plant debris, or compost). They can form
some shallow vertical burrows where they temporarily escape from drought,
heat, and disturbances. |
| epilobic:
See prostomium. |
| exotic:
Introduced through human activity to an area; from a foreign
location. |
| flared
clitellum: See clitellum. |
| genital
markings: Glandular swellings, pits or grooves of the
epidermis (skin). See genital tumescences. |
| genital
tumescences (GT): (see
Earthworm Anatomy) Areas of modified epidermis without distinct
boundaries, through which follicles of genital setae open. |
| gizzard:
The muscular portion of the digestive system where food
is digested. It is located immediately after the crop, and just before
the intestine. |
| hermaphrodite:
An animal that has both male and female reproductive organs.
|
| indigenous:
Belonging to the local area, native and not imported from
anywhere. |
| infiltration
rate: The amount of time required for a known amount (volume
or weight) of water to soak through the soil. |
| intersegmental
furrow: The area between two consecutive segments. It
is here where the skin is thinnest and where, in pigmented species,
color is lacking. |
| iridescence:
Shimmering colours on the surface of the earthworm's skin
as a result of refracted light. Green and blue are common iridescent
colours. |
| juveniles:
Those earthworms without genital markings such as the
clitellum, tubercula pubertatis, or genital tumescence. This stage
of the life cycle is located between the hatchling phase and the appearance
of genital markings (adult stage). |
| litter:
Dead plant and animal material on the surface of the ground. |
| longitudinal
muscles: See muscles |
| midden:
the mound of soil surrounding the burrows of soil dwelling
organisms. |
| mouth:
The opening to the alimentary canal located in the peristomium. |
| muscles:
Earthworms travel by coordinating two kinds of muscles:
circular and longitudinal muscles. Both are located under the epidermis.
When the circular muscles contract, the segments become thinner (decrease
in segment diameter), the earthworm lengthens and moves forward. When
the longitudinal muscles contract, the segments become thicker (increase
in segment diameter), and the earthworm shortens. |
| Oligochaeta:
One of the taxonomic classes in the phylum Annelida. Members
of this class have segmented bodies, setae on all segments (except
the peristomium and periproct), a true coelom, a closed vascular system,
and crawl using circular and longitudinal muscles. |
ovum (egg):
A mature reproductive cell of female animals. |
parthenogenesis:
Reproduction without fertilisation (joining of egg and sperm).
|
| periproct:
(see
Earthworm Anatomy) The last segment of the earthworm’s body; contains
the anus. |
| peristomium:
(see
Earthworm Anatomy) The first segment of the earthworm’s body; contains
the mouth. |
| pH:
An indication of soil acidity or alkalinity, which is expressed on
a pH scale (0-14). A pH less then 7 is acidic, 7 is neutral, and greater
then 7 is alkaline. |
| pharynx:
The portion of the gut between the mouth and the esophagus. |
| polymorphism:
The occurrence of slightly different looking individuals
within the same species; slight variations within one species. |
| postclitellate
adult: Earthworms who have passed their reproductive period.
They no longer have a clitellum, but do show a discolouration where
the clitellum and genital markings were once located. |
| prostomium:
(see
Earthworm Anatomy) The lobe of skin that projects out in front of the first
body segment (peristomium). It is located above the mouth, and there
are three formations as seen in dorsal view. |
| rhizosphere:
The area immediately around plant roots, including the
roots itself. This is an area of intense microbial activity, where
plants, microorganisms, other soil organisms, and soil structure and
chemistry, interact in complex ways. |
| secondary
annulation: The small furrows (wrinkles) that occur in-between
the intersegmental furrows. |
| segment:
The small rings that surround the length of the earthworm’s
body. They are simply folds in the skin. |
| setae:
(see
Earthworm Anatomy) The bristles (or hairs) that are found on an earthworm’s
body. They help the earthworm to move and act to sense the environment. |
| setal
pairings: (see
Earthworm Anatomy) The arrangement of the setae on the earthworm’s
body. Three arrangements exist: closely paired, widely paired, and
separate. |
| sperm:
Male reproductive cells. |
| spermathecae:
An organ in which sperm are stored. |
| tubercula
pubertatis (TP): (see
Earthworm Anatomy) Glandular swellings that occur on both sides of the
clitellum. They are not always present, and they can be continuous
or discontinuous with the clitellum. Their size and shape may vary
from long narrow bands, triangles, or sucker-like shapes, depending
on the species. |
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