Filo Porifera

EJERCICIO 7113-120(EDITION 14TH)109-119 (EDITION 15TH)

Goals for today• Learn to recognized the Phylum Porifera from

other animals• Learn the main ‘diagnostic’ characteristics• Learn about some sponges biology

PoriferaThese are the simplest

metazoans • Little or no tissue organization• Said to belong to the cellular level of

organization.• No organs, no systems, no mouth, or

digestive tract, only rudimentary nervous integrations.

• No germ layers (so neither diplo or triploblastic)

• Asimetric

Porif

era

Parazoa

Radiata

Deut

eros

tom

ia

Ecdy

sozo

a

Loph

otro

choz

oa

Eumetazoa

Bilateria

Protostomia

Cnid

aria

and

Cten

opho

ra

Parazoa

Ancestral colonialchoanoflagellate

PoriferaMain characteristics of sponges are:

• Pores and canal systems (asconoid, siconoid, and leuconoid)

• Flagellated sponge feeding cells= choanocytes.

• Internal skeletons of spicules or organic fibers (spongin).

• Internal cavity= spongocoel that opens to an osculum

Porifera• Most are marine• Freshwater species are found

in ponds and streams• Solitary or colonial• Adults are sessile

Porifera: Classification

Calcarea: • Spicules of calcium carbonate• Needle-shaped or 3-4 rayed spicules• Canal systems asconoid, siconoid, or

leuconoid• All marine

Asconoide Siconoide Leuconoide

Classes:

Hexactinellida: • 3D, six-rayed spicules• Siliceous spicules forming a network• Body often cylindrical or funnel-shaped.• Canal systems siconoid or leuconoid• All marine, and most deep water spp.

Demospongiae: • Siliceous spicules (not six-rayed),

spongin or both• Canal systems leuconoid• One family freshwater, most marine• Most sponges belong to this class

Porifera: Your TasksExercise 7:

– Phylum: Porifera (sponges)– Class Calcarea

• Genus: Sycon (=Scypha, Grantia)

Sycon has a syconoid canal systemMarine

Porifera: Sycon

1. Put a preserved Sycon in a petri dish for you to take a look at the shape, osculum, and spicules. There is also a model of Sycon, learn about its parts

Porifera: Sycon2. Take a slide from your box with (Sycon, Grantia, or

Scypha) this is a cross section cut: identify the incurrent canal, spongocoel, and the radial canal

Water enters the incurrent canals and passes through minute openings called? ____________

Check your book for answers!

Porifera: Sycon2. Take a slide from your box with (Sycon, Grantia, or

Scypha) this is a cross section cut: identify the incurrent canal, spongocoel, and the radial canal

What is the apopyle? Check your book!

Porifera: Sycon3. Take a slide from your box with (Sycon, Grantia, or Scypha)

in a longitudianal cross section you would see the following specialized cells: what are their function?

Porifera: Your TasksExercise 7:

– Phylum: Porifera (sponges)– Class Calcarea

• Genus: Leucosolenia

Leucosolenia has an asconoide canal system

Porifera: Leucosolenia1. Try to find the osculum. This is a colonial species

of tubular individuals in various stages of development

osculum

Porifera: Leucosolenia

2. Look in the micro a slide of Leucosolenia body and its spicules

Porifera: Your TasksExercise 7:

– Phylum: Porifera (sponges)– Class Hexactinellida

• Genus: Euplectella

Porifera: Your Tasks

Some species of Euplectella have a commensal relationship with a shrimp species. A young male and female shrimp enter the central cavity and live there. As they grow they become too large to escape through the sieve-like covering of the osulum, and so spend their entire life inside the sponge.

1. Look at preserved specimens of Euplectella

Porifera: Your TasksExercise 7:

– Phylum: Porifera (sponges)– Class Demonspongiae

• Gemmulas (asexual reproductive structures)

Gemmules are asexual reproductive structures of freshwater sponges and some marine sponges of the class Demonspogiae

What is their function in reproduction?

Important LinksPorifera

http://bioweb.uwlax.edu/zoolab/Table-Of-Contents.htm

http://faculty.uml.edu/rhochberg/hochberglab/Courses/InvertZool/Quizes/Porifera%20Quiz%201.html

http://www.bumblebee.org/invertebrates/Porifera.htm