Molluscs and Annelids Flashcards
Clade Mollusca 4 Parts A/pseudo/true coelom Blastic? Proto/duetero Symmetry? Segmented? Developed organ systems? Open/closed circulatory system? Skeleton? Digestive system Nervous system
Answers Shell, head/food, visceral mass, mantle True coelom Triploblastic Protostome Bilateral symmetry Unsegemented Well developed Open circulatory system (except cephalopods are closed) Exoskeleton Complex Complex
Head-foot
Foot for locomotion
Visceral mass
Houses major internal organs
Mantle
thin, fleshy membrane; secretes the shell
Hemolymph
Pumped from heart into open cavity where organs are
Radula
Unique to molluscs, not in bivalves; tongue used for scraping/cutting food
Bivalves
Suspension feeding
Adaptive radiation
Rapid diversification after common ancestor migrated to a new environment
Coiling
Spiral winding of shell and visceral mass of gastropods
Torsion
Visceral mass twisted during embryonic development; anus over mouth leads to fouling
Mollusca Clades (5)
Gastropoda - “stomach foot” snails, slugs, conchs
Bivalvia - “two valves” clams, oysters, mussels, scallops
Cephalopoda - “head foot” squids, octopuses, nautiluses
Polyplacophora - “many plates” chitons
Scaphopoda - curved, one-piece shell, mouth with tentacles, absent head, tusk shells
Mollusca Bivalvia Clam Umbo Adductor Muscles Mantle Visceral Mass Foot Gills Heart Stomach Digestive Glands Intestine Gonad Kidney Labial palps
Function
Origin of shell
Tubular muscles at ends; close shell and hold valves
Secretes protective shell
Soft portion of the body
Movement
Suspension feeding, gas exchange
Receives oxygen from gills and pumps through arteries
Food digestion
Secretes digestive enzymes into stomach
Digestion of food and absorption of nutrients
Reproduction
Filters wastes from hemolymph and eliminates from body
Secretes mucus onto gills
Open Circulatory Capillary replacement
Sinuses that fill with hemolymph and allow for gases and nutrients to reach all cells and organs
Suspension feeding in bivalvia
Gills covered in a mucus to trap food particles
Gills ciliated to move particles to mouth
Do bivalvia have radula?
No
Clade Cephalopod Modified \_\_\_\_\_ in head region Funnel - Food chain role? Circulatory system?
Answer Foot excurrent siphon that works with the muscular mantle in propulsion Predators Closed
Cephalopod adaptation for predation (3)
Closed circulatory system
Eyes
Ink sac
Cephalopoda: Squid Parts
Mantle
Tentacles
Arms
Funnel/siphon
Eyes
Gills
Ink sac
Pen
Function
Muscle that fills with water on relaxation & expels water through excurrent siphon on contraction
Two longer appendages used to capture prey
Eight shorter appendages used to manipulate food
Muscular siphon enables water to be expelled out for locomotion. Retractor muscles can change funnel direction
Prey detection, observe surroundings
Respiration
Gland containing dark fluid that is released when the animal is alarmed
Near squid’s fin end, internal stiffening rod
Clade scaphopoda
Tusk shells Body enclosed in curved, one-piece shell open on each end Mouth has tentacles Absent head Entirely marine
Clade Polyplacophora
"Many plates" Elongated, flat body 8 dorsal plates Suction-cup foot Use radula
Clade Annelida Blastic Level of organizatoin Proto/dueto Skeleton Segemented? Circulatory system Digestive system Respiration? Mono/di Muscles
Answers Triploblastic Organ system level of organization Protostome Hydrostatic Segemented (metamerism) - helps with locomotion Closed Complete digestive Through skin, gills, or parapodia Monoecious Longitudinal and circular
Setae
Chitin based; small, hairlike bristles used for locomotion
Benefits of segmentation
Foundation for specialization of body regions; Swimming, burrowing, and feed movements are more effective; allows for highly developed organ systems
Annelida Clades (3)
- Polychaeta (paraphyletic) - marine forms (Nereis), clamworms (many setae; parapodia present)
- Oligochaeta (paraphyletic) - earthworms (few setae)
- Hirudinida - leeches (no setae)
