Phylum Porifera (Parazoa)

Question 1

Habitat of porifera

Answer 1

mostly marine, with some freshwater

Question 2

how do porifera feed

Answer 2

active filtering

Question 3

size of porifera

Answer 3

less than 2 meters

Question 4

what do porifera lack

Answer 4

organs, sensory systems, tissues

Question 5

when do the porifera fossils date back to

Answer 5

early cambrien period

Question 6

Basic body plan of sponges

Answer 6

1. built to create a water current through the body to filter food
2. mass of cells embedded in gelatinous mesophyll
3. pinacocytes: skin cells
4. Choanocytes: filtering collar cells
5. Archaeocytes: ameboid
6. water flow driven by flagella choanocytes

Question 7

3 levels of complexity of sponges

Answer 7

1. asconoid
2. synconoid
3. leuconoid

Question 8

what 2 sponges are radially symmetrical and which one is asymmetrical

Answer 8

1. ascanoid
2. syncanoid

asymmetrical
1. leucanoid

Question 9

what is the sponge skeleton made of

Answer 9

collagen fibrils and spicules

Question 10

What do leuconoid secrete

Answer 10

a form of collagen traditionally know as spongin

Question 11

what are spicules made of

Answer 11

silica or calcium carbonate

Question 12

what are choanocytes

Answer 12

Flagellated collar cells
• Lines canals and filter chambers
• Structurally and genetically similar to choanoflagellate protozoans

Question 13

what are pinacocytes

Answer 13

• Epithelial like cells on exterior surfaces, some are contractile

Question 14

what are archeocytes

Answer 14

amoeboid cells in the mesophyll which

1. ingest food
2. differentiate into other cell types

Question 15

Function of sclerocytes

Answer 15

secrete spicules

Question 16

function of spongocytes

Answer 16

secrete spongin

Question 17

collencytes

Answer 17

secrete collagen

Question 18

what type of digestion do sponges possess

Answer 18

intracellular

Question 19

how is food phagocytized

Answer 19

by

1. archeocytes
2. choanocytes
3. pinacocytes
4. pinocytosis
5. direct absorption

Question 20

how do sponges handle respiration and excretion

Answer 20

via diffusion

Question 21

2 types of asexual reproduction for sponges

Answer 21

Bud formation

Fragmentation followed by regeneration

Question 22

what are the 2 types of bud formation in sponges

Answer 22

1. external buds

2. Gemmules

Question 23

what is the function of a gemmule

Answer 23

1. its a resistant life stage with a protective covering

2. survive adverse conditions

Question 24

sexual reproduction term used for sponges

Answer 24

monecious meaning having both male and female reproductive cells in the same body

Question 25

what type of sexual reproduction do sponges use

Answer 25

broadcast fertilization

1. take in sperm from exterior and fertilize internally

Question 26

what do sponge zygotes hatch into

Answer 26

swimming parenchymula larva which swim and settle else where

Question 27

what is sexual reproduction inversion

Answer 27

A hollow blastula forms then inverts to become amphiblastula

Question 28

3 classes of sponges

Answer 28

o calcarea
o hexactinellida
o demospongiae (most abundant)

Question 29

description of class Demospongiae

Answer 29

o Siliceous spicules, or sponging
o Includes the only family of freshwater sponges
o Very diverse yet only leuconoid canal system found in this class

Question 30

description of class calcarea

Answer 30

o calcareous spicules
o includes species with asconoid, syconoid, and leuconoid canal systems
o only extant class with the asconoid canal system

Question 31

description of class hexactinellida

Answer 31

o Structurally very different from other 2 classes
o 6 rigid siliceous spicules fused into rigid structure (glassy looking)
o body consists of continuous syncytial tissue