Porifera (sponges)

Question 1

lack

Answer 1

-tissues
-organs

Question 2

symmetry

Answer 2

• no symmetry
  -radial symmetry in advanced taxa

Question 3

body plan

Answer 3

-acoelomate
-2 layers of cells
1. epidermis-thin flat cells
2. choanocytes- collar cells

Question 4

function of choanocytes

Answer 4

• single flagellum with collar around
• lines interior of body cavity

Question 5

what is the gelatinous layer between the epidermis and choanocytes?

Answer 5

Mesochyme

Question 6

amoebocytes

Answer 6

-free moving
-secrete the matrix
-produce spile-like structures (spicules)

Question 7

the body cavity contains numerous … with one large opening called the…?

Answer 7

pores and chambers
osculum

Question 8

how it works

Answer 8

-small openings all over epidermis
-inner canal lined with choanocytes, their beating flagella set up a water flow
-food particles captures by collar
- water passed into spongocoel, and out through the osculum

Question 9

reproduction

Answer 9

asexual
-budding
-fragmentation(reformation of body after being broken)
-gemma (amoebocytes surrounded by a capsule)
sexual
-egg + sperm
-sexes may or may not be separated