Invertebrates

Question 1

Sponge Structure

Answer 1

asymmetric, no fixed shape. skeleton of fibers called spicules. no tissues or organs. groups of cells not surrounded by membranes. cells relatively unspecialized. cell differentiation is fully and easily reversible

Question 2

Sponge Feeding

Answer 2

suspension feeders. water drawn through body pores. algal symbionts to provide fixed carbon (common among invertebrates)

Question 3

Sponge Defense and attack

Answer 3

toxins, bright warning colouration, spicules. some sponge toxins work against other sponges for space competition. self-nonself recognition, memory

Question 4

Sponge reproduction

Answer 4

asexual-fragmentation, budding

sexual-sequential hermaphrodites, prevents self fertilization

Question 5

Cnidarian body forms

Answer 5

polyp-attached to substrate

medusa-bell-shaped, free-floating

Question 6

Cnidarian structure

Answer 6

nerve net, chemical and mechnical sensors, some have eyes
contractile cells provide motility but no true muscle, originates in epiderm, gastrodermis extends into mesoglea (some species have contractile cells originating in mesoglea)

Question 7

Cnidarian feeding

Answer 7

predatory and algal symbionic life style

nematocyst-injects painful, paralytic toxin

Question 8

Cnidarian reproduction

Answer 8

asexual-budding

sexual-larva is small ciliated planula

Question 9

Flatworms

Answer 9

triploblastic, protostomate, acoelomatous, flattened body for gas exchange

Question 10

Planarians

Answer 10

mainly carnivores
mouth leads to gastrovascular cavity
cephalization/rudimentary brain, eye spots for orientation (negatively phototatic)
asexual reproduction by transverse fission and regeneration
sexual-hermaphroditic individuals, gonopore receives semen, echange is reciprocal. penis fencing

Question 11

Tapeworms

Answer 11

endoparasitic, nutrients pass directly across body wall of worm. conver food to eggs and sperm (10 000-100 000 fertilized eggs/day)

Question 12

Metameric segmentation

Answer 12

Serial repetition of segments

Question 13

Tagmatization

Answer 13

modification and specialization of segments

Question 14

Annelids

Answer 14

segmented worms

oligochaetes-metameric segmentation and polychaetes-differentiated segments

Question 15

Oligochaetes

Answer 15

earthworms and some freshwater and marine relatives

Question 16

Oligochaetes locomotion

Answer 16

alternating contraction of circular and longitudinal muscles, working against the coelomic fluid isolated in each segment

Question 17

Oligochaetes circulation

Answer 17

closed, oxygen absorbed across the skin, highly vascularized for this function, carried by hemoglobin and oxygen-binding proteins, pseuohearts, contractile vessel walls

Question 18

Oligochaetes feeding

Answer 18

deposit feeder, ingest soil, extract nutrients and leave behind castings

Question 19

Oligochaetes reproduction

Answer 19

sexual (simultaneous hermaphroditism)

asexual (fragmentation, parthenogenesis)

Question 20

parthenogenesis

Answer 20

embryo development without fertilization

Question 21

Mollusc body structure

Answer 21

coelomatous, unsegmented

Question 22

Generalized mollusc

Answer 22

muscular foot-locomotion attachment burrowing
visceral mass-internal organs, gill and anus open to mantle cavity.
mantle-secretes the shell, calcium carbonate in a protein matrix.
radula-toothed scraping tool

Question 23

Mollusc circulation

Answer 23

closed in cephalopods, open in others

Question 24

Chitons (polyplacophorans)

Answer 24

grazyers in intertidal region, oval bodies, 8 dorsal plate

Question 25

Gastropods

Answer 25

snails, slugs, 60 000-75 000 species consituting 80% of all molluscs. Dr Louise Page. only molluscs on land. Mantle cavity modified to a lung. grazers, predators. torsion

Question 26

Torsion

Answer 26

180 degree twisting of visceral mass, assymetric growth and muscle contraction on one side of embryo. mass redistribution?

Question 27

Bivalves

Answer 27

clams, scallops, mussels. dorsal hinge, shells left-right. adductor muscles hold shells together. gills collect o2 and food particles, trapped in mucus. usually sedentary, burrowing. scallops more active

Question 28

cephalopods

Answer 28

octopi, squids, nautiluses. eject water through siphon to produce rapid directed movements, allows vertical movement, 3D. Predators with complicated brains and sense organs. most intelligent invertebrates

Question 29

Nematode

Answer 29

commonly called roundworm, unsegmented and pseudocoelomatous with complete digestive tract, cryptospecies

Question 30

Nematode lifestyle

Answer 30

free-living, parasitic.

Question 31

Trichniella spiralis

Answer 31

causes trichinosis, from undercooked pork and game meat

Question 32

Guinea worm

Answer 32

recently almost eradicated

Question 33

Diversity of nematode

Answer 33

25 000 known, 500 000 undescribed

Question 34

Cryptosepcies

Answer 34

look similar, diff in genital anatomy and game recognition factors

Question 35

Interesting facts on nematodes

Answer 35

about 80% individual animals are nematodes. 1 000 000 in 1cubic m of soil. chromosome diminution-fragment and lose embryonic cell dna 20% genome remains in differentiated cells cyrptobiosis-suspended animation, stopped metabolic processes anhydrobiosis-extreme dessication tolerance, trehalose replaces water

Question 36

Caenorhabditis elegans

Answer 36

best understood animal, model organism for developmental genetics. 959 somatic cells, completel cell lineage known "theworm"

Question 37

Arthropods

Answer 37

most successful of all animal phyla in terms of diveristy (2/3 animal species are arthropods)

Question 38

Arthropod clades

Answer 38

chelicerates myriapoda hexapoda crustacea

Question 39

Chelicerates

Answer 39

spiders, mites, ticks, scorpions, cephalothorax, cherlicerae (fangs), no sensory antennae, simple eyes iwth 1 lens

Question 40

Myriapoda

Answer 40

centipedes, millipedes. mandibles, pair of sensory antennae, uniramous appendages, compound eyes

Question 41

Hexapoda

Answer 41

insects, uniramous appendages, 3 pairs of legs on thorax, 1 pair of sensory antennae, flight, metamorphosis

Question 42

Crustacea

Answer 42

crabs, lobsters, barnacles, 2 pairs sensory antennae, mandibles, biramous appendages

Question 43

General arthropod features

Answer 43

segmentation, jointed appendages, exoskeleton- chitin and protein, extensive cephalization, receptors for sight taste smell touch