Lumbriculus variegatus
WOWBug
Blackworm
Human
Kingdom
Animalia
Animalia
Animalia
Phylum
Arthropoda
”jointed foot”
Annelidia
“tiny rings”
Chordata- has
backbone
Insect
Oligochaeta-
Mammalia- nurse
young
Class
Oligo= few
Chaeta= hairs
on each body segment
Posterior
Anterior
Anterior = head
Posterior = tail
Wider, Blunter, More Colorful
End
Narrow and Active End of
worm
Used for probing and foraging Responsible for gas exchange
for food
Blood travels toward head
Require Nutrients
Fresh water invertebrate that feeds on decaying
vegetation and microorganisms
Reproduction
Hermaphroditic – contain both male and female sex organs [like earthworm]
1. Sexual - Sperm exchanged > produce cocoons containing 4-11 fertilized eggs
After 2 weeks > new worm emerges about 1 cm in length
2. Asexual- regeneration - can be divided into smaller pieces and form
new worm
Cellular Respiration
Occurs in tail> forms right angle at water surface > gas exchange
occurs between outside air and pulsating blood vessel
Nervous System
Nerve Cord_- runs entire length of body- located beneath intestines
Movement
PN, prostomial nerves; CG, cerebral ganglion; n1-n4, segmental nerves 1-4;
VNC, ventral nerve cord.
1. Muscles- 2 Layers Line Body- provide movement
- controlled by Nerve Cord
Circular - around body
Longitudinal- length of body
- Together cause constricting and lengthening followed by increasing
diameter and shortening
- allow worm to move in corkscrew fashion in water, swimming short
distances or crawl through soil
2. Chaetae - 2 pairs of bristles located on each segment
- used to anchor worm and increase traction
- help worm crawl
Digestion/Excretion
- has complete digestive tract
including mouth and anus
Circulation System
- consists of dorsal, ventral and lateral vessels
Contracting muscles around posterior vessel form waves “like opening and
closing fist” and move blood from posterior end toward anterior end
Blood flow
Starts at posterior end “pulses” through dorsal vessel toward anterior end
Returns to tail through ventral vessel no “pulsing”
Lateral vessels supply blood to segments
Types of Circulatory Systems1. Closed- blood moves through body in vessels [arteries/veins]
2. Open- blood not contained in vessels, blood bathes all internal
organs
BLACKWORMS HAVE A CLOSED CIRCULATORY SYSTEM
Respond to Environment
Protective Response
When at surface of water, tail of worm can detect shadow [ using
photoreceptors ] or sudden vibration
Responds by quickly contracting its muscles, withdrawing tail from predator
When anterior end is touched, it will change direction of movement
When posterior end is touched, moves forward very quickly