Bio 108 - Lecture 18 Flashcards
Clade Bilateria
- Most animals belong to bilateral
- Bilateral symmetry
- Triploblastic
Cephalization
Differentiation of a head region
Phylum Acoela
- Mostly marine worms
- Part of flatworm phylum
- No body cavity
- No brain
- Basal to rest of bilateria
Phylum Platyhelminthes
Platy =
Helminth =
- Acoelomate, flat, minimal cephalization
- Flat worms
- No circulatory system or digestive system
= Flat
= Worm
Lophotrochozoa
- Split in protostomia
Two class of Platyhelminthes
1) Class Tubellaria
2) Class Cestoidea
Class Turbelaria Characteristics
- Flatworms
- Covered in cilia
- Have ventral nerve cords
- Brain
- Eject food through mouth (no anus)
- Most predatory
Class Cestoidea Characteristics
- Tapeworms
- Entirely endoparasitic
- Lack digestive system
- Scolex
- Proglottids used for reproduction
Scolex
Modified front end of Cestoidea for holding on to hosts gut
Cestoidea Life Cycle
- Eggs eaten by intermediate host
- Egg develops into larvae that encyst in tissues of intermediate host
- Intermediate host eaten by final host
- Larvae develops into tapeworm of final host
- Reproduce sexually in definitive host
Dog tapeworms
Echinococcus
Phylum Brachipoda
Branch =
- Lamp shells
- One of four lophophore-bearing phyla
- Suspension feeding using paired lophophores
- Deep waters
= arm
6 Lophophore Phylas
1) Platyhelmenthes
2) Rotifera
3) Ectoprocta
4) Branchiopoda
5) Mollusca
6) Annelidia
Phylum Ectoprocta
Ecto=
Proct =
- U shaped gut, anal opening on outside of lophophore
- All colonial
- Differentiated species
- Some colonies can move
= outside
= anus
Phylum Annelida
Annulus =
- Segmented Worms
- 3 Classes, most belong to class Polychaeta
- Separated by internal septa
- Eucoelomate
- Closed circulatory system
= ring
Three Classes of Annelida
1) Class Polychaeta
2) Class Oligochaeta
3) Class Hirudinea
Class Polychaeta
Poly=
Chaeta =
- All marine
- Fleshy lobes that beat chaetae
- Head and parapodia more developed in moving species
- Errant polychaetes are predatory
- Sedentary Polychaetes ingest substrate
- Suspension feeders / Deposit feed
- Free spawning
- Trochophore larvae are planktonic, subsequent larvae leading benthic lives
= many
= bristle
Class Oligochaeta
Oligo =
- Still have a few chaetae
- Earthworms
- Hermaphrodites, transfer sperm by copulations
- Direct development
- Useful in composting
- Most of canada was de-wormed by glaciation
= few
Copulation
- Reproduction in worms
- each worm acts as both male and female
- produces gelationous cocoon with secretions from clitellum
- Deposits egg in cocoon, solides cocoon forwards and deposits sperm, fertilization if external
Class Hirudinea
Hirudo =
- Leeches
- Mostly freshwater, some marine and terrestrial
- Have clitellum, but lack chatae
- Predators of soft body invertebrates
- Some feed on blood
- Blood feeders secrete anaesthetic and anticoagulant
- Used for medicine
= Leech
Phylum Mollsuca Characteristics
Moll=
- Characterized by calcareous shell enclosing soft body
- Shell secreted by thin later called mantle
- Muscular foot used for movement
- Organs contain visceral mass above foot
- Mouth an organ called radula
- Gills for gas exchange
- Open circulatory system
- Trocophore
Three classes of Mollusca
1) Gastropoda
2) Bivalia
3) Cephalopoda
Class Gastropoda
Gastro=
Pod=
- Snails
- Undergo torsion, anal opening is over the head
- Lungs rather then gills
- Protected by nematocysts of cnidarians
= Stomach
= Foot
Nudibranchs
Shell-less marine gastropods
- Sea slugs
