Marine Biology Lecture 4
April 10, 2006 (part)
I.
II.
III.
Phylum Platyhelminthes: flatworms
A.
General appearance
B.
Feeding behavior
C.
Movement
Phylum Nemertea: ribbon worms
A.
General appearance
B.
Feeding behavior
1.
Major predator on smaller animals of the intertidal
2.
Key structure: eversible proboscis
a.
Description of structure and how it works. Know!
C.
Movement
Phylum Annelida: segmented worms
A.
Focus: Class Polychaeta (the marine segmented worms)
1.
Major features
B.
Examples of intertidal polychaetes (habitat, feeding, respiration, and other
aspects)
1.
Free-crawling predators (Nereis, Glycera)
a.
Habitat
b.
Feeding

sensory structures

eversible proboscis
c.
Respiration
2.
Tube worms with tentacular crowns
a.
Habitat
b.
Feeding/tube building

Structure of tentacular crown and how it works

pinnules

food groove and sorting
c.
Respiration
3.
Deposit feeders
a.
Habitat
b.
Feeding: structures and behavior

Note different mechanisms of bringing food to mouth
c.
Respiration

Gas exchange over the surface of the tentacles

Some species with separate, blood-filled gills
4.
Chaetopterus: tube-dwelling, mucous-bag feeder
a.
Habitat
b.
Feeding

Mucous bag

Water current. How created (name structures)

Role of ciliated cup and ciliated groove
c.
Regeneration: The magic of segment 14
C.
Reproduction
1.
Most polychaetes just shed eggs and sperm, but some species are more
elaborate
2.
Epitokes (Nereidae and others)
a.
Formation
b.
Appearance
c.
Behavior
d.
Adaptive value
3.
Trocophore larvae
Study questions
1.
Phylum Platyhelminthes
a.
Where might you find Platyhelminthes in the marine environment?
b.
Describe how members of Phylum Platyhelminthes feed. What do they eat?
c.
Describe how members of Phylum Platyhelminthes move.
2.
Phylum Nemertea
a.
Where might you find Nemerteans in the marine environment?
b.
At what time of day are you likely to find them actively feeding?
c.
Describe how members of Phylum Nemertea feed, being sure to indicate several
special adaptations they have to subdue their prey (i.e. don’t just tell me they have
an eversible proboscis. You should describe the feature of that proboscis.)
d.
Describe how members of Phylum Nemertea move.
3.
What key features distinguish Polychaetes from other members of Phylum Annelida?
4.
For each of the four intertidal polychaetes, describe feeding to the level presented in
lecture. The key is to name key structures and explain how they work. You may wish to
include diagrams in your explanation.
5.
For each of the four intertidal polychaetes, describe the major locations of gas exchange.
6.
What is an epitoke? Describe the formation, appearance, behavior and adaptive value of
epitokes.
7.
What type of larvae do most marine polychaetes have?
8.
How well can polychaetes regenerate? Provide an extreme example…