Worm facts
By David F. Salisbury
March 11, 2002
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SIZE: the thickness of an eye lash and one millimeter (1/250th of an inch) long.
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COLOR: transparent.
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HABITAT: compost heaps.

FOOD: bacteria that it sucks up using a muscular pump near its head.

LIFE CYCLE: it takes three-and-a-half days at room temperature for a fertilized
egg to develop into a reproductive adult.

LIFE SPAN: two weeks; after that it literally begins to fall apart; when food is
scarce it begins producing a special type of larvae that can live for several
months without feeding.

GENES: 20,000; in 1998 it was the first multi-cellular organism to have its
genome fully sequenced.

DEVELOPMENT: the only multi-cellular organism for which development has
been completely mapped; cell divisions occur the same way every time; every
cell division from the first division of the fertilized egg until the last cell is added
during larval development is known.

CELLS: 959 somatic cells; there are actually fewer cells in the adult because
skin cells and some others fuse to form multi-nucleated cells during
development.

ORGANIZATION: cells are organized into familiar tissues or organs, including a
nervous system, digestive tract, reproductive system, excretory system, even a
primitive heart.

NERVOUS SYSTEM: 302 neurons; although it doesn’t have a brain a majority of
the neurons are clustered in the head region.

REPRODUCTION: two modes of sexual reproduction: hermaphroditic (sperm
and eggs provided by the same animal) and male/hermaphrodite mating (sperm
from male, eggs from hermaphrodite); each worm produces about 250 offspring
so one animal can produce over 60,000 grandchildren in just one week.

MOVEMENT: wild-types spend ¾’s of their time moving forward and ¼
backward; researchers have found uncoordinated (unc) mutants that cannot
move backwards at all or that roll continually as they move.
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