Download Annelida

http://surferjerry.com/wp-content/uploads/2009/02/giant-south-african-earthworm.png
ANNELIDA
By Emily Chu and
Wonhyoung Kim
Segmented
worms
CLASSES

Oligochaeta (earthworms and relatives)

Polychaeta (polychaetes)

Hirudinea (leeches)
Leech
Earthworm
http://www.cheshirewildlifetrust.co.uk/IMA
GES/watch_earthworm.jpg
Christmas tree worm
http://www.microteufel.com/TripReports/M
aui/Aquarium/IMG_0063s.jpg
http://www.io.com/~dierdorf/leech.jpg
BODY CAVITY (COELOM)

Present

Annelida=coelomate (has a true coelom)
http://biology.unm.edu/ccouncil/Biology_203/Images/SimpleAnimals/Coelomate.JPG
BODY SYMMETRY

Bilateral symmetry
http://www.mun.ca/biology/scarr/142003_Annelida.jpg
NERVOUS SYSTEM


Have brain-like pair of cerebral ganglia
Ventral nerve cords with segmental ganglia (runs
through length of body)
CIRCULATORY SYSTEM


Closed circulatory system—blood contained
within vessels
Blood contains oxygen-carrying hemoglobin
DIGESTIVE SYSTEM


Earthworms eat through the soil, extracting
nutrients as the soil passes through the
alimentary canal.
Have digestive tract
http://johnson.emcs.net/life/images/earthworm.jpg
EXCRETORY SYSTEM

Metanephridium=excretory tubes


Remove waste from the blood and coelomic fluid
through exterior pores
Nephrostomes=ciliated funnels
LOCOMOTION/MUSCULATURE
Chaetae=bristles that provide traction for
burrowing
 Each segment is surrounded by a longitudinal
muscle, which is in turn surrounded by circular
muscle.
 Contractions of these muscles allow for
movement.

http://oceanexplorer.noaa.gov/explorations/03windows/logs
/jul28/media/naut_allseate_600.jpg
SKELETAL TYPE


No true skeleton
Hydrostatic skeleton—controlled by coelomic
fluid
SENSORY
STRUCTURES/FEATURES



Simple sensory structures
Single-celled structures detect light, chemicals,
pressure waves, and contact
Some polychaetes have ocelli (“little eyes”)
REPRODUCTION
Hermaphrodites
 Earthworms cross-fertilize

Two earthworms exchange sperm then separate
 Received sperm are stored temporarily while the
clitellum secretes a mucous cocoon
 Cocoon slides along the worm, picking up eggs and
then the stored sperm


Some earthworms can also reproduce asexually
by fragmentation followed by regeneration
Clitellum
http://static.howstuffworks.com/gif/willow/earthworm-info0.gif
GAS EXCHANGE
SKIN! This is the respiratory organ.

Hemoglobin in blood carries oxygen

Some polychaetes have gills
http://upload.wikimedia.org/wikipedia/commons/e/ea/Christmas_tree_worms.jpg
OTHER UNIQUE FEATURES
Today, leeches are used to drain blood that
accumulate in tissues following certain injuries.
 Leeches secrete hirudin (prevents blood from
clotting, which allows leech to feed)
 Hirudin has the potential to be used in the future
to dissolve blood clots that form during surgery or
as a result of heart disease.

THE END!!!!
Just kidding…
http://www.breaktaker.com/albums/pictures/animals/LaughingCat.jpg
QUIZ TIME!
1.
What is the primary respiratory organ?
2.
Describe the annelid’s circulatory system.
3.
Give two examples of methods of reproduction
and explain each.
4.
Which of these phyla consists of species with a
coelom?
A.
B.
C.
D.
Porifera
Cnidaria
Annelida
Platyhelminthes
CHECK YOUR ANSWERS!
1.
The skin
2.
Closed circulatory system
3.
Sexual—two hermaphroditic annelids align and
exchange spermclitellum secretes cocoon
Asexual—fragmentation and regeneration
4.
C. Annelida