Download Phylum Annelida

Phylum Annelida
the segmented worms
Vocabulary Annelida
1. Setae
11. Closed circulatory system
2. Parapodium 12. Probiscus
3. Crop
13. Eucoelomate
4. Gizzard
14. Ecology
5. Typhlosole 15. Anticoagulant
6. Aortic arch 16. Detritus
7. Nephridium 17. Monoecious
8. Clitellum
18. Dorsal
9. Seminal receptacle
19. Ventral
10. Chitin
20. Hirudinea 22. Polychaeta
21. Oligochaeta 23. Annelida
Annelida Vocab
3. crop- a thin-walled portion of the gut that is
used for the storage of food prior to digestion
4. gizzard- is an organ found in the digestive
tract that is used for grinding up food
5. Typhlosole-dorsal flap of the intestine that
runs along most of its length;function is to
increase intestine surface area for more efficient
absorption of digested nutrients.
6. Aortic arch- series of hearts
12. Probiscus- the tubular feeding and
sucking organ
13. Eucoelomate- an organism that has
a complete body cavity where the
ectoderm and the endoderm is lined
by mesoderm
15. Anticoagulant-substance that
prevents coagulation; that is, it stops
16. Detritus- non-living particulate
organic material; typically includes
the bodies or fragments of dead
organisms as well as fecal material
Agree or disagree
1. All worms are found in Phylum
Annelida.
2. Earthworms are the largest group of
annelids.
3. Annelids have bilateral symmetry.
Taxonomy
• Kingdom: Animalia
Phylum: Annelida
Class: Oligochaeta
Polychaeta
Hirudinea
ANNELIDA - “fireworm”
General Characteristics of Annelids
• “Annellus” means “little rings
”
• Segmented body
Bilaterally
• ___________
symmetrical
• True coelom, often divided by
Eucoelomate
internal partitions…….___________
• Most have external bristles called
setae
_______
General Characteristics of Annelids - cont
• Some have fleshy protrusions called
parapodia
___________.
• The number of setae and the
presence or absence of parapodia is
the basis for dividing the annelids
into 3 classes:
– Oligochaeta
– Polychaeta
– Hirudinea
Body Cavity
Eucoelomate
completely
Have a “true” body cavity that is ____________
mesoderm
surrounded by ___________
ectoderm
coelom
mesoderm
Gut
endoderm
Annelid Characteristics
The Coelom
closed fluid filledectoderm
• is a ______,
cavity
gut
that surrounds the ____.
• the fluid within acts as a
Skeletal
_____________
system
Annelida Characteristics
Nervous system
•Anterior nerve ring, ganglia,
and ventral nerve cord
Locomotion
longitudinal and __________muscles
• both ___________
circular
setae
•most have __________
(chitonous bristles
secreted by the epidermis) that aid in
locomotion and burrowing
Annelida Characteristics
Skeletal System
•fluid in coelom acts as a hydrostatic skeleton
Gas exchange
•mainly by diffusion through the skin
Digestive System
Circulatory System
• complete with
•__________
closed circulatory
mouth & _______
anus
_______
• regional specialization
system composed of
blood vessels (some of
which are contractile and
act as “hearts”)
Excretion
• excretion is accomplished by organs called
nephridia
___________
Reproduction
*normally sexual or hermaphroditic
Protostomes
• Blastopore develops into the mouth
• Anus develops later in a different
spot.
Mouth Formation
Blastopore becomes the mouth and the anus
forms secondarily
Future anus
blastopore
archenteron
(primitive gut)
mouth
Questions
1. What kind of coelom do all annelids
have?
2. What kind of symmetry do all
annelids have?
3. What are setae?
4. How many openings to the digestive
system?
5. What type of skeletal system do
annelids have?
Class Polychaeta
Class Polychaeta
• all _____________
marine
2/3 of all known
• this class contains _____
Annelids.
• have a well developed head with specialized
sense organs
Class Polychaeta
(Poly = many, chaeta= setae)
setae (chitonous bristles
• have many _______
secreted by the epidermis)
• these setae are arranged in bundles on
paddle-like appendages called parapodia
setae
Questions
1. What does Polychaeta mean?
2. Where do you find most polychaets?
• CHUNKING.. Read on pg 213 &
discuss 3 external anatomical
features specific to polychaetes.
Polychaete worms – Thermal vents
Class Polychaeta
•Many are filter-feeders
with specialized structures
Extended
Contracted
Class Oligochaeta
Class Oligochaeta
Class Oligochaeta
The earthworm
• Most familiar member:________________
• Generally live in the soil or fresh water.
• Have few setae (bristles)
oligo
chaeta = setae)
•(_____=
few, ______
• Usually feed on detritus
_________
(decaying organic matter)
• Have specialized digestive system to
obtain the maximum amount of nutrients
out of the detritus (e.g. gizzard, crop…)
Class Oligochaeta
Locomotion
Circular
muscle
contraction
Longitudinal
muscle
contraction
Movement
1.
2.
3.
4.
Posterior setae anchor
Circular muscles contract
Anterior setae anchor
Circular muscles relax and
longitudinal muscles contract
Muscles contract against “Hydrostatic
Skeleton”
Class Oligochaeta
Reproduction
• usually monoecious
•Cannot fertilize own eggs
• cross-fertilize by
sperm
exchanging ______
clitellum
testis
CHUNKING QUESTIONS
• Read on page 217
• Discuss the external anatomical
features specific to oligochaetes.
Class Oligochaeta – The Earthworm
Feeding and Digestion
• Soil is sucked into the mouth by the
muscular pharynx.
• Soil then passes to the crop
(temporary storage area)
• From the crop it
moves to the
gizzard
– The gizzard
grinds the soil
• As the soil moves
through the
intestines,
nutrients are
absorbed by the
blood.
• The typhlosole (infolding of intestinal
wall) increases the surface area for
absorption.
• Undigested material is eliminated
through the anus.
Intestine
Typhlosole
Neural Control
• Most body segments contain a single
ganglion (cluster of nerve cells)
– Nerves branch from them
– Carry impulses to the muscles
• Anterior segments have several
ganglion fused together  brain
– Process information from sensory
structures
Respiration
• Oxygen and Carbon Dioxide diffuse
through the skin.
– Skin needs to be moist
– Secretion of mucus helps keep them
moist
Excretion
• Earthworms excrete liquid waste
through long tubules called
Nephridia
Circulation
• Closed circulatory system
• 5 aortic arches link ventral and dorsal
blood vessels.
Internal View of an Earthworm
Ecology
Earthworms can be considered “mini
topsoil factories” because they bring
_________
nutrients up to the surface layers
of the soil and assist in breaking
organic matter.
down ________
•
Earthworm Trivia
• If all the material ever moved
through earthworms was piled up,
the heap would rise 30miles, more
than 5 times the height of Mount
Everest!!
•
Questions
1. How do earthworms breathe?
2. How many hearts do earthworms
have?
3. Why are earthworms so important to
the soil?
Class Hirudinea
Class Hirudinea
• Usually freshwater but there are
some marine and terrestrial species
• Most are parasites
• No setae
• No parapodia
• Have 2 suckers
Class Hirudinea
proboscis for feeding
• have an extendable ________
Class Hirudinea
Locomotion
They use their
anterior and
posterior
suckers
_________
to
move.
Ecology
• Although some leeches are parasitic
blood suckers (can be temporary or
permanent), many are predators.
Ecology
medicinally
• Leeches have been used __________
since the 19th century.
Ecology - cont
• Currently they are used to increase
blood flow following reconstructive
surgery
• Hirudin is a powerful
anticoagulant that is found in the
____________
salivary glands of leeches
Questions
• Why are leeches used in the field of
medicine?
• What structures do leeches lack?
• What structures do leeches use to
move?
Nova - Leeches
Annelida Review: Write the questions & use the book & your notes to answer the questions.
1. Identify w factors used as the basis for dividing annelids into 3 classes.
2. List the advantages of segmentation.
3. How does an earthworm exchange oxygen and carbon dioxide with its environment?
4. What is metamerism? Identify 3 reasons why it is advantageous? (textbook) pg.
211
5. What is tagmatization? (textbook)
6. Identify the 3 classes of Annelids and give an example of each.
7. Use a flow chart (arrows) to trace the involvement of setae and muscle
contractions as an earthworm moves.
8. Use a flow chart to trace the feeding and digestion process of earthworms.
9. What 2 structures do leeches lack?
10. How are leeches used medicinally following surgical procedures?
11. What is the function of the following structures:
A. Typhlosole B. Crop C. Gizzard
D. Setae
E.
Proboscis
F. Clitellum
G. Aortic arches
H. Nephridia
I. Parapodia
12. Identify the 3 parts of the nervous system of annelids.
13. What does “annellus” mean?
14. Which is the largest class in phylum Annelida?
15. Why do Oligochaets have a specialized digestive system?
16. How does sexual reproduction take place in earthworms? What 2 structures must
line to ensure the successful delivery of sperm?
17. Explain how each class gets it’s name:
A. Polychaeta
B. Oligochaeta
C. Hirudinea