Sponges, Cnidarians, and Ctenophores

1
Sponges, Cnidarians, and Ctenophores

• Chapter 33

2
Phylum Porifera

• Section 33.1

3
Phylum Porifera
Latin for Pore-Bearing
Asymmetric Body Structure
4
Sponges

• Aquatic animals
• Represent transition from unicellular to
  multicellular life
• No true tissue or organs
• 5,000 species (most marine)
• Various colors, shapes, sizes, etc.
• Adults are sessile

5
(No Transcript)
6
Sponge Body Plan

• Two layers of cells separated by mesohyl
  (jellylike substance)
• Body wall forms a hollow cylinder that is open at
  the top

7
More Sponge Parts

• Choanocytes (collar cells) flagellated cells
  that draw water into the sponge
• Ostia (pores) pores that penetrate the body wall
  that allow water into the sponge
• Osculum opening at the top of the sponge

8
Sponge Support System

• Simple skeleton made up of spongin and/or
  spicules
• Spongin tough, flexible protein fibers
• Spicules tiny, hard particles of calcium
  carbonate or silicon dioxide
• shaped like spikes

Spicules
Spongin
9
Sponge Anatomy
10
Feeding Digestion

• Filter feeders of plankton and other small
  organisms
• Steps in feeding digestion
• Choanocytes beat draw water into ostia
• Then collect food from water
• Nutrients pass from choanocytes to amoebocytes
• Crawling cells that deliver nutrients to rest of
  the body
• Wastes and CO2 diffuse into the water and goes
  out the osculum
• video

11
Water Flow
Video
12
Asexual Reproduction

• Regeneration
• regrowth of missing cells
• Budding
• sometimes the bud breaks off the parent and
  becomes a new organism
• or it may remain attached to the parent and
  develop into a sponge colony

13
Environment gone bad?

• Gemmules food filled ball of amebocytes
  protected by protein spicules
• Can survive harsh conditions
• Similar to endospore of bacteria

14
Sexual Reproduction

1. Sperm of one sponge enters pores of a different
   sponge
2. Choanocytes engulf the sperm
3. Sperm transferred to ameobcytes
4. Then transferred to egg in mesohyl
5. Egg is fertilized
6. Swimming larva leaves the sponge and settles on
   an object to become an adult

video
15
Hermaphrodites

• Why doesnt self-fertilization usually occur in
  an hermaphroditic species?
• Answer
• Less genetic diversity thus less of a change to
  survive an environmental change (evolution would
  not occur as much)

16
Phyla Notecards

• First side
• Phylum name
• Example organisms
• Drawing of organism
• With color!
• Opposite side
• Body symmetry
• Mobility (adult larval stages)
• Feeding methods
• Reproductive methods
• Defense mechanisms
• Environment/habitat

17
Cnidaria Ctenophora

• Section 33.2

18
Phylum Cnidaria
19
General Characteristics

• Radial symmetry
• Have tissues and simple organs
• Aquatic (mostly marine)

20
Phylum Cnidaria
21
Body Plans

• Medusa bell-shaped specialized for swimming
• Polyp vase-shaped specialized for sessile living

22
More Body Parts

• Two cell layers
• Epidermis outer layer
• Gastrodermis inner layer
• Mesoglea
• jellylike material between two layers

23
Continued

• Gastrovascular cavity center of body with a
  hollow gut and mouth
• Tentacles flexible extensions surrounding the
  mouth
• Moves food in

24
Feeding Defense

• Cnidocytes specialized cells used for defense
  and capturing prey
• Gives the phylum its name!
• Nematocyst organelle within cnidocyte with a
  long filament and a poison tip
• Trigger response

Video
25
Nervous System

• Nerve net diffused web of interconnected nerve
  cells
• No brain
• No cephalization
• Can respond to stimuli
• Nerve net ? contractile cell ? contraction of
  whole body
• Can control swimming feeding

26
Classification

• Four classes
• Class Hydrozoa
• Class Cubozoa
• Class Scyphozoa
• Class Anthozoa

27
Class Hydrozoa

• Colonial organisms (combo of polyp medusa form)
• Each organism has a specialized function for the
  colony
• Exception hydras only polyps, NOT colonial
• Examples Portuguese man-of-war, hydra, and
  Obelia

Man of War
Obelia
Video
Hydra
28
Class Cubozoa

• Commonly known as box jellies
• Cube shaped medusa
• Some have cnidocytes that can cause death to
  humans
• Example Sea wasps

Sea Wasp
29
Class Scyphozoa

• Commonly known as jellyfish
• The medusa form is dominant
• Some have poisonous nemotocytes that can cause
  pain and death

Life Cycle video
30

• Biotechnology with Jellies video

31
Class Anthozoa

• Meaning flower animals
• Dominant form polyp
• Examples coral sea anemone
• Some have symbiotic relationships with other
  species
• Coral with algae
• Sea anemone with clownfish

Nemo!
Coral And Algae
32
Phylum Ctenophora
Video
33
Distinguishing Characteristics

• Meaning comb holder
• Commonly called comb jellies
• Move by beating cilia
• Contain colloblasts that secrete a sticky
  substance that blinds prey
• Do not have cnidocytes (like other jellies)

34
Continued

• Apical organ sensory structure that determines
  orientation in the water
• Bioluminescence production of light through
  chemical reactions

35
Phyla Notecards

• First side
• Phylum name
• Example organisms
• Drawing of organism
• With color!
• Opposite side
• Body symmetry
• Mobility (adult larval stages)
• Feeding methods
• Reproductive methods
• Defense mechanisms
• Environment/habitat

36
Class Notecards

• First side
• Class name
• Example organisms
• Drawing of organism
• With color!
• Opposite side
• Unique characteristics
• Description of representative organism
• Info about an organism listed in the book
• Environment/habitat