Bio 108 - Lecture 18 Flashcards Preview

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Flashcards in Bio 108 - Lecture 18 Deck (26):
1

Clade Bilateria

- Most animals belong to bilateral
- Bilateral symmetry
- Triploblastic

2

Cephalization

Differentiation of a head region

3

Phylum Acoela

- Mostly marine worms
- Part of flatworm phylum
- No body cavity
- No brain
- Basal to rest of bilateria

4

Phylum Platyhelminthes
Platy =
Helminth =

- Acoelomate, flat, minimal cephalization
- Flat worms
- No circulatory system or digestive system
= Flat
= Worm

5

Lophotrochozoa

- Split in protostomia

6

Two class of Platyhelminthes

1) Class Tubellaria
2) Class Cestoidea

7

Class Turbelaria Characteristics

- Flatworms
- Covered in cilia
- Have ventral nerve cords
- Brain
- Eject food through mouth (no anus)
- Most predatory

8

Class Cestoidea Characteristics

- Tapeworms
- Entirely endoparasitic
- Lack digestive system
- Scolex
- Proglottids used for reproduction

9

Scolex

Modified front end of Cestoidea for holding on to hosts gut

10

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

11

Dog tapeworms

Echinococcus

12

Phylum Brachipoda
Branch =

- Lamp shells
- One of four lophophore-bearing phyla
- Suspension feeding using paired lophophores
- Deep waters
= arm

13

6 Lophophore Phylas

1) Platyhelmenthes
2) Rotifera
3) Ectoprocta
4) Branchiopoda
5) Mollusca
6) Annelidia

14

Phylum Ectoprocta
Ecto=
Proct =

- U shaped gut, anal opening on outside of lophophore
- All colonial
- Differentiated species
- Some colonies can move
= outside
= anus

15

Phylum Annelida
Annulus =

- Segmented Worms
- 3 Classes, most belong to class Polychaeta
- Separated by internal septa
- Eucoelomate
- Closed circulatory system
= ring

16

Three Classes of Annelida

1) Class Polychaeta
2) Class Oligochaeta
3) Class Hirudinea

17

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

18

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

19

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

20

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

21

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

22

Three classes of Mollusca

1) Gastropoda
2) Bivalia
3) Cephalopoda

23

Class Gastropoda
Gastro=
Pod=

- Snails
- Undergo torsion, anal opening is over the head
- Lungs rather then gills
- Protected by nematocysts of cnidarians
= Stomach
= Foot

24

Nudibranchs

Shell-less marine gastropods
- Sea slugs

25

Class Bivalia
bi=
Valv=

- Clams, oysters, scallops
- two hinged shells
- No radula
- Some sessile but most are sedentary
- Many eaten for food, used for pearls
- Invasive pest
= two
= door

26

Class Cephalopoda
Cephalo =

- Squids, octopus
- Long tentacles arranged around mouth
- Most have radula modified as biting beak / poison
- No external shell
- Some have internal shell remnants
- Only molluscs to have closed circulatory system
- Jet propulsion
- Maternal care / direct development
- Excellent vision
- Intellegent
= Head