Topic 21

Question 1

phylum porifera

Answer 1

basal animals that lack true tissue - sponges

Question 2

sponges are sessile…

Answer 2

but have a motile larval stage

Question 3

do sponges have true tissue

Answer 3

no

Question 4

what gives sponges structural support

Answer 4

spicules and spongin

Question 5

spicules

Answer 5

tiny needles or rods of silica or calcium carbonate - maintain shape and structure of sponge

Question 6

spongin

Answer 6

fibrous collagen-protein network for support

Question 7

cell types in sponges

Answer 7

porocytes, epidermal cells, choanocytes and mobile amoebocytes

Question 8

porocytes

Answer 8

tubular cells that make up pores of a sponge, allowing water to flow through

Question 9

epidermal cells

Answer 9

outer layer of tightly packed cells

Question 10

choanocytes

Answer 10

line inner cavity of the sponge - generate water currents by beating flagella and capturing suspended food particles - deliver oxygen and nutrients to the sponge while removing waste and CO2

Question 11

mobile amoebocytes

Answer 11

found in the mesohyl - transport nutrients to other cells of the sponge body, make materials for skeletal fibres and differentiate into other cell types

Question 12

mesohyl

Answer 12

gel-like, non-cellular matrix between the epidermis and choanocyte - provides support and structure - contains mobile amoebocytes and skeletal elements

Question 13

what kind of feeders are sponges

Answer 13

suspension feeders

Question 14

how do sponges get food into their body

Answer 14

water is drawn by beating choanocyte flagella through pores (ostia) into a cavity called spongocoel and out through an opening (osculum)

Question 15

how do sponges extract food

Answer 15

collar cells extract food particles (protist plankton) using mucus-covered microvilli which are then engulfed through phagocytosis and digested (endoceullular digestion) or transferred to amoebocytes

Question 16

how do nutrients get mobed

Answer 16

amoebocytes transport them

Question 17

hermaphrodites

Answer 17

have both male and female reproductive organs

Question 18

what does sperm develop from in sponges

Answer 18

modified choanocytes

Question 19

what does eggs develop from in sponges

Answer 19

modified amoebocytes

Question 20

what do zygotes develop into in sponges

Answer 20

motile ciliated larvae within the mesohyl

Question 21

how can sponges reproduce asexually

Answer 21

fragmentation and budding

Question 22

how do sponges keep predators away

Answer 22

producing toxic chemicals

Question 23

what do sponges form symbiotic mutualisms with

Answer 23

unicellular algae

Question 24

what does clade eumetazoa include

Answer 24

all animals excluding sponges

Question 25

most basal eumetazoan phyla

Answer 25

ctenophora and cnidaria

Question 26

what do most basal eumetozoans exhibit

Answer 26

radial symmetry and are diploblastic

Question 27

what animals are in phylum cnidaria

Answer 27

jellyfish, sea anemones, and corals

Question 28

body plan and digestive system of cnidarians

Answer 28

sac-like body plan and central gastrovascular cavity

Question 29

how many opening is there to the gastrovascular cavity in cnidarians

Answer 29

one opening - mouth and anus

Question 30

cnidocytes

Answer 30

tantacles with stinging cells that surround the mouth/anus opening of cnidarian

Question 31

what are cnidarians bodies made of

Answer 31

outer epidermis from the ectoderm and an inner gastrodermis from the endoderm

Question 32

what seperates the epidermis and gastrodermis in cnidarians

Answer 32

a gelatinous non-cellular matrix called the mesoglea

Question 33

how does gas exchange happen in cnidarians

Answer 33

vio diffusion across the epidermis

Question 34

variations in body plan of cnidarians

Answer 34

sessile polyp or motile meduse

Question 35

sessile polyp

Answer 35

attaches to a substrate with its oral end upward - sea anemone

Question 36

motile medusa

Answer 36

moves feely through the water using a hydrostatic skeleton with oral opening downwards - jellyfish

Question 37

nematocysts

Answer 37

special cells in cnidocytes that deliver stinging toxins to prey to immobilize them

Question 38

what two major clades did cnidarians evolve from

Answer 38

clade medusozoa (meduse stage) and clade anthozoa (polyps)

Question 39

what do hydrozoans do

Answer 39

alternate between polyp and medusa form

Question 40

what is medusa the prominent stage in

Answer 40

scyphozoans (true jellyfish) and cubozoans (box jellyfish)

Question 41

what are anthozoans

Answer 41

corals and sea anemones

Question 42

anthozoans only occur as...

Answer 42

polyps