Chapter 33- Invertebrates

Question 1

suspension feeders

Answer 1

• animals that capture food particles suspended in the water that passes through their body, which in some species resembles a sac perforated w/ pores
• sponges

Question 2

spongocoel

Answer 2

a central cavity of a sac-shaped suspension feeder

Question 3

osculum

Answer 3

larger opening through which water exits a sac-shaped suspension feeder

Question 4

choanocytes

Answer 4

• collar cells
• flagellated cells lining the interior of the spongocoel
• engulf bacteria and other food particles by phagocytosis
• similar to choanocytes, supporting evidence that animals evolved from a choanoflagellate-like ancestor

Question 5

mesohyl

Answer 5

• gelatinous region b/w 2 layers of cells in the body of a sponge
• contains tough skeletal fibers produced by amoebocytes
• location of fertilization

Question 6

amoebocytes

Answer 6

• cells that move through the mesohyl using their pseudopodia and have many functions
• take up food from surrounding water and from choanocytes, digest it, and carry nutrients to other cells
• manufacture skeletal fibers
• capable of becoming other types of sponge cells, giving the sponge body remarkable flexibility
• make sperm and eggs

Question 7

hermaphrodites

Answer 7

• each individual functions as both male and female in sexual reproduction by producing sperm and eggs
• almost all sponges exhibit sequential hermaphroditism: they function first as one sex and then as the other

Question 8

coelenterates

Answer 8

• grouping name
• hollow gut ?
• no coelom ?
• nerve net ?

Question 9

polyp

Answer 9

• cylindrical forms that adhere to the substrate by the aboral end of their body (end opposite the mouth), and extend their tentacles, waiting for prey
• sessile
• mouth up

Question 10

medusa

Answer 10

• resembles a flattened, mouth-down version of a polyp
• moves freely in the water by a combination of drifting and contractions of its bell-shaped body
• mouth down

Question 11

cnidocytes

Answer 11

• cells unique to cnidarians that function in defense and prey capture
• contain cnidae, capsule-like organelles that are capable of exploding outward

Question 12

nematocysts

Answer 12

specialized type of cnidae that contain a stinging thread that can penetrate the body wall of the cnidarian’s prey

Question 13

protonephridia

Answer 13

• simple excretory apparatus in flat worms that functions mainly to maintain osmotic balance with surroundings
• consists of networks of tubules w/ ciliated structures called flame bulbs that pull fluid through branched ducts opening to the outside
• “before kidney”

Question 14

flame bulbs

Answer 14

• ciliated structures on tubules in protonephridia that pull fluid through branched ducts opening to the outside
• part of flatworm excretory system

Question 15

planarians

Answer 15

• freshwater species of flatworm in class Turbellaria and genus Dugesia
• abundant in unpolluted ponds and streams
• prey on smaller animals or feed on dead animals
• move by using cilia on ventral surface, gliding along a film of mucus
• head equipped w/ eyespots and lateral flaps that function to detect specific chemicals
• more complex and centralized nervous system than cnidarians
• hermaphrodites that reproduce both sexually and asexually
• ventral nerve cord
• regenerates
• pharynx

Question 16

alimentary canal

Answer 16

• digestive tube w/ 2 openings, a mouth and an anus

- first found in rotifers

Question 17

parthenogenesis

Answer 17

• a type of asexual reproduction in which a species consists entirely of females that produce more females from unfertilized eggs
• found in rotifers and others

Question 18

ectoprocts

Answer 18

• colonial animals that superficially resemble clumps of moss
• colony is usually encased in an exoskeleton studded with pores through which the lophophores extend
• sea mat
• looks like big gelatinous brain
• marine and freshwater

Question 19

brachiopods

Answer 19

• lamp shells
• resemble clams and other hinge-shelled molluscs, but the 2 halves of the brachiopod shell are dorsal/ventral rather than lateral, as in clams

Question 20

foot

Answer 20

muscular extension of mollusks that is usually used for movement

Question 21

visceral mass

Answer 21

part containing most of the internal organs of a mollusc

Question 22

mantle

Answer 22

a fold of tissue that drapes over the visceral mass and secretes a shell (if applicable) in molluscs

Question 23

mantle cavity

Answer 23

• a water-filled chamber produced when the mantle of a mollusk extends beyond the visceral mass
• houses the gills, anus, and excretory pores

Question 24

radula

Answer 24

strap-like organ in most mollusks that is used to scrape food like a cheese grater

Question 25

torsion

Answer 25

developmental process of gastropods in which the visceral mass of a developing embryo rotates up to 180 degrees, causing the anus and mantle cavity to wind up above its head

Question 26

ammonites

Answer 26

shelled cephalopods that were the dominant invertebrate predators of the seas for 100s of millions of years until the mass extinction 65.5 million years ago

Question 27

cuticle

Answer 27

tough external coat that an ecdyzoan molts as it grows

Question 28

molting

Answer 28

• ecdysis

- shedding of cuticle with growth

Question 29

open circulatory system

Answer 29

• heart propels fluid called hemolymph through short arteries and then into spaces called sinuses surrounding the tissues and organs
• hemolymph reenters the heart through valved pores
• found in arthropods and many molluscs

Question 30

chelicerae

Answer 30

claw-like feeding appendages that serve as pincers or fangs for chelicerates

Question 31

eurypterids

Answer 31

• earliest chelicerates
• water scorpions up to 3 m’ long
• extinct

Question 32

arachnids

Answer 32

• group comprising the bulk of modern chelicerates that includes scorpions, spiders, ticks, and mites
• have a cephalothorax that has six pairs of appendages: the chelicerae; a pair of appendages called pedipalps that function in sensing, feeding, or reproduction; and four walking legs

Question 33

book lungs

Answer 33

stacked platelike structures contained in an internal chamber used for gas exchange in most spiders

Question 34

mandibles

Answer 34

jaw-like appendages on the myriapod head

Question 35

water vascular system

Answer 35

• a network of hydraulic canals branching into extensions called tube feet that function in locomotion and feeding
• unique to echinoderms

Question 36

hirudin

Answer 36

naturally occurring peptide in the salivary glands of medicinal leeches that has a blood anticoagulant property

Question 37

malpighian tubule system

Answer 37

• a type of excretory and osmoregulatory system found in some Atelocerata (Insects and Myriapoda) and arachnids
• consists of branching tubules extending from the alimentary canal that absorbs solutes, water, and wastes from the surrounding hemolymph
• wastes then are released from the organism in the form of solid nitrogenous compounds

Question 38

tube feet

Answer 38

• extensions of hydraulic canals in a water vascular system of an echinoderm
• function in locomotion and feeding

Question 39

tracheal systems

Answer 39

• gas exchange in insects
• branched, chitin-lined tubes that infiltrate the body and carry oxygen directly to cells
• opens to the outside of the body through the spiracles, pores that control air flow and water loss by opening or closing