Annelids and Molluscs

Question 1

What are some examples of Annelids?

Answer 1

Nereis, Earthworms, Leeches

Question 2

WHat are the 2 major clades of Annelida?

Answer 2

Errantia, Sedentaria (some with a clitellum)
earthworms and leeches = clitellata

Question 3

Why are Annelids lophotrochozoans?

Answer 3

ancestrally there is a trochopore larva as part of the life cycle

Question 4

What are general characteristics of annelids?

Answer 4

cylindrical body with distinct segments
digestive system with an anterior mouth and posterior anus
anterior cerebral ganglia to connect an extensive nervous system

Question 5

What is gas exchange like in annelids? (aquatic and terrestrial)

Answer 5

aquatic have gill-like organs
terrestrial exchange gases across their skin
a closed circulatory system if present moves dissolved gases through the body

Question 6

What is a closed circulatory system?

Answer 6

blood flows through connected blood vessels pumped by muscular heart(s). The blood flows through vessels to supply tissues with nutrients

Question 7

What are the waste filtering organs in terrestrial annelids called?

Answer 7

metanephridia

Question 8

What is a nephron?

Answer 8

the glomerulus, capsule, renal tubes and collecting ducts = nephron = the functional unit of the vertebrate kidney

Question 9

What is reproductive systems of annelids like?

Answer 9

can be monoecious (clitellates) (hermaphroditic
or dioecious (errantia)

Question 10

What is the clitellum? (earthworms - cross-fertilize)

Answer 10

thickened glandular structure of the body wall near the anterior region found in earthworms and leeches. it secreted a sac in which eggs are stored

Question 11

How do earthworms feed?

Answer 11

they are detritivores - ingest sediment, digesting the organic matter it contains and excreting mineral particles

Question 12

What are Invasive Jumping Worms?

Answer 12

native to asia spread throughout North America in potted plants, soil, compost etc.
jumping worms as they mov like a snake and appear to be jumping when disturbed

Question 13

How do invasive jumping worms affect soil quality?

Answer 13

after feeding on organic matter, they excrete grainy-looking hard little pellets that alter the texture and composition of soil, which provides poor structure and water retention for many forest understory plants and garden plants

Question 14

What do medicinal leeches do?

Answer 14

produce a natural anesthetic and an anticoagulant and suck blood from the surface of skin

Question 15

What are features of some annelids enabling food filtering from water?

Answer 15

tentacle development

Question 16

What is an example of a marine annelid predator?

Answer 16

Polychaete Bristle Worm (Errantia)

Question 17

describe parchment tube dwelling worms?

Answer 17

Chaetopterus sp. Water moves through tune and food is trapped in worms mucus net to be ingested

Question 18

WHy are Mollusks lophotrochozoans?

Answer 18

there is a trochophore larva as part of life cycle

Question 19

What are ancestral characters of Mollusks?

Answer 19

Foot
Visceral mass
Mantle and mantle cavity
mouth cavity possesses a specialized protrusible, rasping organ - radula

Question 20

What are the 4 classes of molluscs?

Answer 20

Chitons, Gastropods, Bivalves, Cephalopods

Question 21

How is shell produced in molluscs?

Answer 21

mantle secretes shell

Question 22

How does pearl formation occur in clams and oysters?

Answer 22

starts when an irritant is established between the mantle and shell
covers the irritant for protection with layers of nacre substance from mantle (used to create shell) concentric depositions forms a pearl

Question 23

What is the Nervoud System in Molluscs like?

Answer 23

a nerve collar and 2 logitudinal nerve cords

Question 24

What type of circulatory system do most molluscs have?

Answer 24

open circulation

Question 25

WHat is open circulatory system?

Answer 25

blood flows through a vessel with muscular thickenings that act as a pump. Blood empties into an open body cavity to supply tissues with nutrients and is returned to the circulation

Question 26

What are features of gastropods?

Answer 26

most have a single, spiraled shell many shells have a hardened protective plate called the operculum on the back of the foot

Question 27

What are evolutionary changes in gastropod shell architecture?

Answer 27

Planospiral sjhell was not as compact change in symmetry of the shell created a shift in the weight to one side of the animal, thus the shell needed to shift upwards and posterior to offset theis weight

Question 28

What is feeding like in gastropods?

Answer 28

mostly herbivorous - use radula

Question 29

What is the radula?

Answer 29

a toothed chitinous structure used for scraping or cutting food before the food enters the gut

Question 30

What is a venomous gastropod?

Answer 30

cone snails - use radula cusps or teeth as harpoons

Question 31

What is torsion?

Answer 31

during development, 1 side of the visceral mass grows at a much faster rate than the other; rotates visceral mass 180 degress relative to the head-foot

Question 32

What are the advantages of torsion?

Answer 32

gills positioned anteriorly = better respiration head retracted first = better protection

Question 33

How does Gastropod respiration work in aquatic and terrestrial species?

Answer 33

aquatic have gills terrestrial have a well vascularized mantle ('lung')

Question 34

How does reproduction work in gastropods?

Answer 34

many marine are dioecious, terrestrial monoecious

Question 35

What are nudibranch gastropods?

Answer 35

soft-bodied marine gastropods that feed on algae, sponges and cnidarians tentacles - cerata - aid in gaseous exchange when stinging cells consumed they pass through cnidosacs where they are stored until use for defense

Question 36

WHat are adaptations of Cephalopod molluscs?

Answer 36

dorsal-ventral axis became elongated, and anterior-posterior axis became compressed migration of the head to the ventral part of the body where it fused to the foot

Question 37

What are some examples of Cephalopods?

Answer 37

octopus, Chambered nautilus, Squid

Question 38

How do Cephalopods feed?

Answer 38

predacious carnivores powerful parrot-like beak and radula salivary glands are modified poison glands

Question 39

How do cephalopods move?

Answer 39

swimmers; streamlined body and tentacles and fins serve as stabilizers by means of jet propulsion - using muscular mantle and siphon/funnel (expelling water)

Question 40

What happened to cephalopod shell?

Answer 40

sokme coiled and non-coiled but lost in derived lineages (octopus)

Question 41

WHat are the shells on living cephalopods like?

Answer 41

Nautilus has a coiled, chambered shell Cuttlefish have an internal, non-coiled, chambered shell - cuttlebone squids have an internal thin shell made of chitinous material - pen octopuses have no shell

Question 42

What do cephalopods have for protection?

Answer 42

ink sacs, well developed sense organs incl camera type eye, well-developed brains; excellent learning behaviours

Question 43

WHat type of circulatory system do cephalopods have?

Answer 43

closed circulatory system

Question 44

WHat are the shells of Bivalvia of Mollusca like?

Answer 44

divided into 2 equal valves mantle tissue with 2 centers of calcification and indent in anterior-posterior margins joined at dorsal midline closed via adductor muscles

Question 45

Describe bivalve burrowing?

Answer 45

often burrow in sand and sediment using their muscular foor bring water into and out of hte shell through opening called siphons

Question 46

WHat is the importance of gills with cillia in Bivalvia?

Answer 46

moving water in, through and out of the animal; for filter feeding and oxygenation

Question 47

What is an example of a soft bottom burrower? (Bivalvia)

Answer 47

razor clam

Question 48

What is an example of a attached surface dweller? with what? (Bivalvia)

Answer 48

Blue mussels with byssal threads

Question 49

WHat is an example of unattached surface dwellers? what are they?

Answer 49

scallop, locomotion by rapid clapping of valves using powerful adductor muscle

Question 50

WHat is an example of hard bottom burrowers? what are they?

Answer 50

shipworms - capable of burrowing into hard surfaces such as coral and wood

Question 51

What could be a adaptation for dispersal of some mussels?

Answer 51

Lapsillis mussel can use lure to squirt young into mouth of smallmouthbass

Question 52

WHere dooes the clam glochidia live??

Answer 52

larval stage attaches to the gills of fish for further development