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
• Other annelids:
• Earthworms
• Leeches
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
Photoreceptors
Obtain Nutrients/Create energy


Fresh water invertebrate that feeds on
decaying vegetation and microorganisms
Cellular Respiration
Occurs in the tail, it takes in oxygen through skin
 forms right angle at water surface
 gas exchange occurs between outside air and
pulsating blood vessel
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- not common
2. Asexual- regeneration - can be divided into smaller pieces and form
new worm
Nervous System
Nerve Cord_- runs entire length of body- located beneath intestines
PN, prostomial nerves; CG, cerebral ganglion; n1-n4, segmental nerves 1-4;
VNC, ventral nerve cord.
Movement : Crawling or Corkscrewing
1. Muscles
Two 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
crawling 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
- Excretes waste gasses through
its skin
Earthworm
Blackworm
Circulation System
- consists of dorsal, ventral and lateral vessels
How does it work?
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
photoreceptors – nerve cells that can detect light
Rapid Reflex- responds by quickly contracting its muscles, withdrawing tail
from predator
So…..
HOW DOES IT?.....