LEARNATHON
III

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Theory:

Other adaptations present in earthworms are continued below:
 
3. Burrowing:
 
The earthworm's body is flexible, having muscles that help in its movement. There are two types of muscles - circular and longitudinal muscles that help in the movement and burrowing into the subsoil.
 
456px-Earthworm_movement_all.jpg
Earthworm movement using circular and longitudinal muscles
 
The ring-like segments annuli are covered on the lower surface of the body in setae or small bristles. The setae are tiny hair-like structures that are found projecting out under the body of the earthworm. The worm uses setae to move through the soil and provides the worms grip and anchorage in the burrows.
 
Earthworm_segments_Labeled_Segments.jpg
Setae of earthworm

4. Aestivation:
 
When the environmental conditions in the earthworm's habitat change, for example, when the soil becomes too hot or too dry, the earthworms become inactive through aestivation.
 
In the process, the earthworms move deeper into the soil, coil into a ball, excrete mucus that protects it, and lower the metabolic rate to reduce water loss.
 
711px-Aestivating_earthworm_norwich_vermont_July_2010_cropped.png
Aestivation in earthworms
 
Earthworms remain in this dormant condition until favourable conditions returns. The earthworms come out of the burrow when it rains during the rainy season.
 
5. Nocturnality:
 
Earthworms are sensitive to light. It spends its day in the burrows, soil or leaf litter. It is usually found in burrows during the day to avoid light and find them on the surface during the night.

Earthworms do not have eyes or ears and thus cannot see or hear. It senses light through light-sensitive cells (Photoreceptors) present in its skin. Earthworms react negatively to bright light
(Photophobic).
 
They are sensitive to vibrations.
 
Important!
Earthworms are called "Farmer’s friends". When earthworms digest organic matter, it excretes a nutrient-rich waste product called castings, used as Vermicompost.
Reference:
https://commons.wikimedia.org/wiki/File:Earthworm_movement_all.jpg
https://upload.wikimedia.org/wikipedia/commons/6/6a/Earthworm_segments_Labeled_Segments.jpg
https://commons.wikimedia.org/wiki/File:Aestivating_earthworm_norwich_vermont_July_2010_cropped.png