Phylum Porifera, Placozoans

Question 1

Two phlya that lack specialized/unique tissues

Answer 1

Phylum Porifera and Phylum Placozoa; unspecialized cells can develop into a range of structures, no true tissues or organs

Question 2

What does lack of specilization mean for sponges?

Answer 2

means that the organism can be broken
apart –can reintegrate with other broken pieces OR develop into another independent sponge

Question 3

Porifera/Sponge Anatomy parts

Answer 3

sponge wall(spongin, spicules), inner sponge(choanocytes, pores, osculum)

Question 4

Sponge wall

Answer 4

composed of SPONGIN (tough outer covering) increases rigidity of structure; covered with SPICULES (spines) to have protection from predators

Question 5

Inner sponge

Answer 5

lined with cells called CHOANOCYTES –which beat their flagella to pull in water & food particles through PORES in outer wall, particles then digested in inner cells; Filtered water goes out through opening (OSCULUM) at top of sponge

Question 6

Porifera: Are all sponges found in ocean (marine, saltwater systems)?

Answer 6

NO!! –there are a few hundred FRESHWATER species including
multiple species in North America and at least one here in Ohio(Spongilla lacustris)

Question 7

Placozoa

Answer 7

Very simple, tiny (size of a sesame seed), multicellular animals, lack specialized tissues, feed through version of osmotrophy

can reproduce sexually, but primarily use asexual reproduction…where two sides pull apart into two pieces, like a piece of gum/taffy