Warm up.

Name that symmetry

Answer: Bilateral

Answer: Radial

Answer: Radial

Answer: Asymmetry!Sea sponge

Asymmetry – non-symmetrical

Phylum: Porifera"I drink no more than a sponge" Francis Rabelais

Phylum Porifera

• From Greek ‘poros’ meaning ‘passage’ or ‘pore’ Sponges have tiny openings all over their body • Therefore Porifera = “pore-bearers”• Most ancient and primitive of all animals• Estimated 5000-10000 species • Most sponges are marine, some live in freshwater

Where are they on the tree of life?

• You tell me?

“I never wanted to be different; I just wanted to be me”

• Sponges are different than other animals.• Originally thought to be plants because “sessile”• Have no: Mouth, head, muscles, nervous

system, digestive tract, circulatory organs, true tissue layers, organ system.

• Long thought to be an evolutionary dead end however recently believed to be at the base of the animal tree of life.

Sessile: “fixed in one place”

What do they have?Why are they an animal?

• Collagen- all animals use collagen as an essential structural protein

• Animal embryonic development

• “Motility” of most cells within the sponge

Motile

Structure and Function in Porifera-The 4 Cells

• Epidermal cells

• Pore Cells

• Collar Cells (choanocyte)

• Amoebocytes

Epidermal

- Flat cells form the outer covering.- Respire and excrete via diffusion.

Pore cells

- Cylindrical cells which allow water and food to enter the sponge- The flow of water is driven by current and by

collar cells

Collar cells (choanocyte)

- Inner cell layer of a sponge- Have a flagellum which draws water into the sponge-flagellum also drives food into the collar where they are ingested into the cell body

Amoebocytes

• amoeba-like cells that crawl around the jellylike inner layer of the sponge

• Deliver food and O2

• Absorb nutrients and remove wastes• Make SPICULES which create sponge skeleton• Carry sperm to eggs

http://www.biologyjunction.com/sponges__cnidarian_notes_b1.htm

Activity

• With a partner try and remember the 4 cell types

• Draw the four cell types• Label their parts.• Write brief definition of what they do• Gallery walk (see other drawings get ideas

how other people do their work)

How does a sponge stay standing?

• Spicules • Spongin

Head to Head

Spicules• Created by Amoebocytes • Made from either: -chalklike calcium carbonate (CaCO3) -or glasslike silica (SiO2)• Form the delicate skeleton of the

sponge

Spongin• Softer sponges (like the

ones you can buy to use in the bath) are made up of fibrous proteins called spongin.

• Some sponges contain both spicules and spongin

Spongin Spicules

Evolution of Spicules

Other key words

• Spongocoel – hollow body in the sponges interior. (think coelom)

• Osculum- Opening where water exits the sponge

• Spicules – the skeleton of the sponge (more later)

How does a sponge eat?

• ..\..\..\Lesson Videos\Biology 11\Sponge Feeding.mov.flv

How does a sponge eat?

• Sponges are filter feeders – they sift microscopic food particles from the water that passes through them• All digestion is intracellular • Food particles stick to the collar cells

Collar cells either digest the food or pass them on to the ? (what else digests/delivers food)Amoebocytes

The water flowing through a sponge serves as its respiratory, excretory, and circulatory system.

• Sponges pump huge amounts of water through their body every day

• Roughly one tonne water per ounce of food

Reproduction

Asexual reproduction• “Budding” – a small growth

forms and falls off the sponge starting a new sponge

• “regeneration” Sponges can regenerate from broken pieces

• “Gemmules” sphere-shaped collections of amoebocytes surrounded by spicules. They leave sponge, settle, and wait for improved conditions

Sexual reproduction• Hermaphrodites (both male

and female sexual organs)• Most fertilization is

hermaphroditic• “Broadcast” method of

sperm release. Masses of sperm released into water

• Amoebocytes carries sperm to egg when received.

Gemmulles• “Little gems of life”? “Survival pods”?

• Remember it your way.

• Sphere-shaped collections of amoebocytes surrounded by spicules

• leave sponge, settle, and wait for improved conditions

Gemmules

• Can survive extreme temperatures or drying out

• Some are resistant to freezing• Full of amoebocytes which can grow into any

type of cell necessary for survival

• Why would sponges have evolved Gemmules?

Here comes the Motility

Flagellated larvae

• A sponges larvae have flagellum• Leave via ?• Osculum• Drift/ swim to their new home

• ..\..\..\Lesson Videos\Biology 11\Sponge Spawning.flv