Transcript Annelida By: Omar Abdulkader, Marcus Bray

Annelida
By: Omar Abdulkader,
Marcus Bray
http://www.flickr.com/photos/97968921@N00/1795523221/ (Left)
http://www.flickr.com/photos/pmforster/457146720/ (Right)
Omar Abdulkader
Examples:
• Polychaets (Christmas Tree Worm)
http://www.flickr.
com/photos/tim_
uk/384626933/
Oligochaetes
(Earth Worm)
Leech
http://www.flickr.
com/photos/neil
rsmith/5379460
99/
Omar Abdulkader
http://www.flickr.com/photos/theju/254592404/
Body Symmetry
• Bilateral Symmetry
http://www.flickr.com/photos/35031054@N00/27111691/
Omar Abdulkader
Body Cavity
• Coelom is present, and is separated by
septum.
http://universe-review.ca/I10-82-cavity4.jpg
Omar Abdulkader
Nervous System
• Cerebral Ganglia: A brain like pair of
cerebral ganglia above and in front of
pharynx near mouth.
• Nerve cords that run the length of animal.
• Ring of nerves around pharynx connects
to a subpharyngealganglion, where fused
pair of nerve cords run.
Omar Abdulkader
Circulatory System
• A network of vessels (closed).
• Dorsal and Ventral Vessel connected by
segmental pairs of vessels.
• Dorsal Vessel + 5 pairs of vessels that
circle esophagus are muscular and pump
blood through circulatory system.
Omar Abdulkader
Digestive System
• One long intestine that runs length of
animal (One-way).
http://www.zo.utexas.edu/faculty/sjasper/images/f26.5.jpg
Omar Abdulkader
Excretory System
• Metanephridium: excretory tubes with
ciliated funnels called nephrostomes
• Remove waste from the blood and
coelomic fluid through exterior pores.
• Each segment of the worm has a pair of
metanephridium.
Marcus Bray
Locomotion
• All annelids have a two layer system of
muscle. Longitudinal muscle surrounded
by circular muscle.
• Contraction of these muscle against each
other and the coelomic fluid cause the
organism to move.
• Most annelids have chaetae which are
bristles that provide traction for burrowing.
Marcus Bray
Skeletal Type
• No true skeleton
• Instead muscles work against the noncompressible fluid of the coelom.
(hydrostatic skeleton)
Marcus Bray
Sensory Structures
• No specialized sensory structures other
than nervous system
Marcus Bray
Reproduction
• Annelids are hermaphrodites meaning
they have both sperm an eggs
• Sexual: Annelids reproduce sexually by
aliging themselves in order to exchange
sperm. Then an organ called the clitellum
creates a cocoon which picks up the
sperm as well as and egg and deposits the
fertilized egg in the soil.
Marcus Bray
Gas Exchange
• Skin functions as respiratory organ
• Oxygen and carbon dioxide are
exchanged in skin and oxygen is
transferred to tiny blood vessel in
epidermis.
Marcus Bray
Unique Features/Facts
• Leeches are used in medicine for blood
letting
• Earthworms are beneficial to famrers
because they till the earth and the soil a
good texture
Quiz
1. What bristle-like structures do some
annelids use to burrow?
2. What is the center of an annelid’s
nervous system?
3. What functions as a hydrostatic skeleton
in an annelid?
4. How does and annelid pump blood
through its body?
Marcus Bray
Answers
1.
2.
3.
4.
Chaetae
Cerebral Ganglia
Coelom fluid
By utilizing the muscles in the dorsal
vessel and the five pairs of vessels that
circle the esophogaus.
Marcus Bray