Invertebrates

Question 1

characteristics of sponges?

Answer 1

sedentary, marine
filter feeders - food suspended in water brought in through spongocoel and out of the osculum
lack tissues
flagellum - changes water pressure
choanocyte - generate water current and ingest food by phagocytosis
sequential hermaphrodites - male then female
amoebyctes - digestion/make skeletal fibres

Question 2

what are some features of cnidarians?

Answer 2

true tissues 
sessile and motile e.g jellyfish 
diploblastic and radial body plan 
gastrovascular cavity 
single opening - mouth and anus 
carnivores - tentacles with cnidocytes and nematodysts which eject stinging thread

Question 3

what are the two variations of body plan of cnidarians?

Answer 3

sessile polyp - adheres to substrate by aboral end

motile medusa - mouth on underside

Question 4

features of lophotrochozoans?

Answer 4

have lophophore for feeding
may have trochophore developmental stage
true coelom
hard exoskeleton sometimes

Question 5

what are ectoprocts and brachiopods?

Answer 5

lophophorates
ectoprocts have an exoskeleton and are sessile
brachiopods resemble clams but dorsal and ventral shell halves

Question 6

features of clade mollusca?

Answer 6

muscular foot, visceral mass and mantle
soft bodied most protected by calcium carbonate shell
some have water filled mantle and feed via straplike radula
separate sexes but snails hermaphrodite

Question 7

how do gastropods move?

Answer 7

small rippling movement from cilia, some have a spiral shell and radula to feed

Question 8

features of nematodes

Answer 8

roundworms, have an alimentary canal but no circulatory system
body wall muscles longitudinal - trashing motion when contracted

Question 9

features and examples of arthropods?

Answer 9

segmented body, hard exoskeleton, jointed appendages
covered in cuticle made of chitin and protein
evolution of exoskeleton allowed them to colonize land

Question 10

what are crustaceans?

Answer 10

marine, freshwater or terrestrial
specialised appendages
small ones exchange gases through cuticle, large ones gills

Question 11

what are hexapods?

Answer 11

insects

flight - didn’t have to sacrifce a pair of legs as wings extension of cuticle

Question 12

what are echinoderms?

Answer 12

sessile marine animals
thin epidermis covers exoskeleton of hard calcerous plates
external sexual reproduction
water vascular system with network of hydraulic canals branching into tube feet for locomotion and feeding