Sponges, corals, Pre-bilaterian Life

Question 1

Roughly how many phyla is the animal kingdom divided into?

Answer 1

33

Question 2

7 common animal phyla

CAMP CAN

Answer 2

Cnidaria
Arthropoda
Mollusca
Porifera

Chordata
Annelida
Nematoda

Question 3

What phylum do sponges make up?

Answer 3

Porifera

Question 4

What are the four pre bilatarian early branching phyla

Answer 4

Porifera
Placazoa
Cnidaria
Ctenophora

Question 5

Describe basic features of a sponge body plan?

4 types of cells

Answer 5

Outer cells called Pinacocytes
Inner cells
Pore cells
Collar cells called choanacytes (lining the inner cell endoderm like layer)

Question 6

How do Porifera feed?

Answer 6

Choanocytes (collared cells) use their flagella to create a water current that draws water into the sponge.

Bacteria in the water are trapped in the collar of choanocytes.

Choanocytes chambers

Question 7

What do choanocytes look similar to?

Answer 7

Choanoflagellates

Question 8

Sessile sponge predator example

Answer 8

Deep sea carnivorous sponges which eat small crustaceans

Eg. Harp sponge (Chondrocladia lyra)

Question 9

What are spicules?

Answer 9

Structural and protective components of sponges made of calcium or silica

Question 10

Two functions of sponge spicules

Answer 10

Pointed sponge spicules protect against predators

Modified spicules shaped like hooks can catch prey

Question 11

Cladorhizidae

Answer 11

Family of sponges which are carnivorous and prey on crustaceans and small animals

Question 12

Why might carnivorous sponges have evolved?

Answer 12

As an adaption to a lack of plankton and little filter feeding

Question 13

Placozoa body plan

Answer 13

Upper cell layer (some have cilia, others don’t)
Fibre cells
Lower cell layer (including some secretory gland cells)

Question 14

What are placozoa fibre cells like?

Answer 14

A little like muscle cells - sort of contractile

Question 15

How do placozoa feed?

Answer 15

Secretion of digestive enzymes as they crawl over algae on rocks

Question 16

Approximately how many species of placozoa?

Answer 16

DNA analysis suggests 20

Question 17

What are textbooks incorrect about placozoa?

Answer 17

Most textbooks say there is only one species - Trichoplax adharens however there are actually approximately 20

Question 18

Describe basic cnidarian body plan

Answer 18

Singular opening that functions as both a mouth and anus

No true muscle cells but inner/outer layer cells can be contractile

2 cell layers (epidermis and gastroepidermis)

Mesoglea

Question 19

What are the two cnidarian cell layers?

Answer 19

Epidermis

Gastroepidermis

Question 20

What is a mesoglea

Answer 20

Non connective tissues layer in cnidarians with proteins and polysaccharides

Question 21

Two cnidarian body plans

Answer 21

Polyp form

Medusa form

Question 22

Cnidarian Medusa body plan

Answer 22

Umbrella like structure with mouth/anal opening pointed downwards

More mesoglea

Stuffer mesoglea which gives more rigidity. More active contractile cells which allow it to swim.

Question 23

What does a cnidarian Medusa body plan do that the polyp form doesn’t?

Answer 23

Swim

Question 24

How do cnidarians feed?

Answer 24

Stinging organelles called nematocysts which help them catch prey

Question 25

What do cnidarians eat?

Answer 25

They are predators and eat fish

Question 26

What are cnidarian stinging organelles called

Answer 26

Nematocysts

Question 27

How do nematocysts function?

Answer 27

Cnidoblast cell contains a coiled, hollow and barbed thread that fires out and injects venom (touch sensitive)

Question 28

Oddity cnidarian life cycle

Answer 28

Some can alternate between Medusa and polyp forms

Question 29

Colonial cnidarian example

Answer 29

Portuguese man o’war built of thousands of polyp buds that form a colony

Question 30

Most odd looking cnidarian

Answer 30

Myxozoans - bizarre parasites that look nothing like other cnidarians

Question 31

Example of colonial cnidarian

Answer 31

Coral reefs | Portuguese man o’war

Question 32

What cnidarian has photosynthetic dinoflagellates

Answer 32

Corals - used to get food from sunlight

Question 33

Common name for Ctenophora

Answer 33

Comb jellies

Question 34

Basic body plan of Ctenophora

Answer 34

2 cell layers Radial symmetry Colloblast sticky cells used for predation

Question 35

How do ctenophores predate?

Answer 35

Colloblast sticky cells

Question 36

Which two of the early pre bilaterian branches are predators?

Answer 36

Cnidarian (stinging cells) | Ctenophora (sticky cells)

Question 37

How do Porifera feed?

Answer 37

Filter feeding

Question 38

How do placozoa feed?

Answer 38

Grazing

Question 39

Which of the four early branching pre bilateria lineages have no symmetry?

Answer 39

Porifera | Placozoa

Question 40

Which of the four early branching pre bilateria lineages have radial symmetry

Answer 40

Ctenophora | Cnidarians

Question 41

Nervous system comparison in four early pre bilaterian lineages ?

Answer 41

None have a centra nervous chord Porifera and placozoa have no nerves Cnidaria and Ctenophora have a nerve net

Question 42

Compare basic germ layer in four early pre bilaterian lineages

Answer 42

All have 2 germ cell layers