The Sponges: Phylum Porifer

Question 1

What are 2 main characteristics of porifera?

Answer 1

They lack hox genes (genes that determine the anterior and posterior ends of an organism…) this is why sponges have no symmetry
- they are also sessile in their adult stage, and non-sessile in their larval stage (attached to one spot and do not move)

Question 2

What are 3 morphological figures of sea sponges?

Answer 2

1. no obvious tissue or organs (some basic cells have specialized functions)
2. Structural support comes from spicules –> calcium carbonate or silica hard needles or rods
3. Some sponges have collagen (protein network for support)

Question 3

What is the mesohyl of a sea sponge?

Answer 3

the gelatinous acellular layer between its outer skin and the choanocyte layer (fills gap)

Question 4

What is the role of the choanocyte and the ameobocyte?

Answer 4

the choanocyte sucks up food from the mucus and flagellum and then it passes it to the amoebocyte which carries food and nutrients to other cells or uses energy to make spicules or other structural materials

Question 5

What are spicules?

Answer 5

they are used for support in the sea sponge (the calcium carbonate, silica or collagen material)

Question 6

How do sea sponges eat?

Answer 6

they eat via suspension feeding, they can extract tiny particles like bacterial and it is engulfed by phagocytosis at the base of the choanocyte cell
- then it gets transferred to ameobocyte to transport the nutrients

Question 7

How to sponges reproduce?

Answer 7

most sponges are simultaneous hermaphroditic (both male and female at the same time), but they can be sequential hermaphrodites (initially a female but then turn into a male)

• sponges don’t have ovaries or testes
• mostly internal fertilization but external can occur

Question 8

What modified part of the sponge do the eggs arise from?

Answer 8

amoebocytes (because its a cell with a cytoplasm)

Question 9

what modified part of the sponge does the sperm arise from?

Answer 9

choanocytes (because they are flagellated)

Question 10

How do sponges reproduce in during their sequential hermaphroditism stage?

Answer 10

adult “male” sends sperm from choanocyte to the amoebocyte of “female” and fertilization takes place and then a motile larval stage arises

Question 11

What is one cool thing about sponges?

Answer 11

they can regenerate

Question 12

What are some ecological importance in sponges?

Answer 12

1. They filter feed and therefore clean the water
2. Sponges have symbiotic mutualists with single-celled algae and other organisms that use sponges as a home
3. Only a few are predatory
4. Pharmaceuticals use sponges for antibiotics and anticancer drugs
5. high quality bath and art sponges made from some sponge species