Chapter 26: Sponges and Cnidarians

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Chapter 26 Sponges and Cnidarians
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26-1 Introduction to the Animal Kingdom

• What makes animals different from the previous
  organisms we have covered so far this year?

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The Animal Kingdom
26-1 Introduction to the Animal Kingdom

• Multicellular
• Eukaryotic
• Heterotrophs
• Cells lack
• cell walls
• 95 are
• invertebrates

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26-1 Introduction to the Animal Kingdom
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26-1 Introduction to the Animal Kingdom
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What Animals Do to Survive
26-1 Introduction to the Animal Kingdom

• Feeding
• Respiration
• Circulation
• Excretion

• Response
• Movement
• Reproduction

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1. Feeding
26-1 Introduction to the Animal Kingdom

• Modes of ingestion of nutrients

Carnivores
Detrivores
Herbivores
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2. Respiration
26-1 Introduction to the Animal Kingdom

• Taking in oxygen, releasing carbon dioxide

Lungs
Gills
Skin
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3. Circulation
26-1 Introduction to the Animal Kingdom

• Movement of materials in the body

Diffusion
Heart Pump
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4. Excretion
26-1 Introduction to the Animal Kingdom

• Removal of nitrogen waste out of body to maintain
  homeostasis

Diffusion
Kidney
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5. Response
26-1 Introduction to the Animal Kingdom

• Responding to outside stimuli using nerve cells

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6. Movement
26-1 Introduction to the Animal Kingdom

• Attached to a single spot or motile

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7. Reproduction
26-1 Introduction to the Animal Kingdom
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Trends in Animal Evolution
26-1 Introduction to the Animal Kingdom

• Though there are differences in whether an animal
  has a backbone or not, there are some common
  trends
• 1. Cell Specialization
• 2. Body Symmetry
• 3. Cephalization
• 4. Body Cavity Formation

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1. Cell Specialization
26-1 Introduction to the Animal Kingdom

• Animal cells have evolved to carry out specific
  functions

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1. Cell Specialization
26-1 Introduction to the Animal Kingdom

• Reasons why cell specialization is important
• Allows for animals to perform many different
  functions
• Causes a greater efficiency in survival

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Early Embryonic Development
26-1 Introduction to the Animal Kingdom

• Animals that reproduce sexually begin life after
  fertilization as a zygote (fertilized egg)
• Zygote undergoes a series of divisions
• Blastula forms (simple ball of cells)
• Blastula fold in on itself forming blastopore
• Blastopore leads into a central tube

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Early Embryonic Development
26-1 Introduction to the Animal Kingdom
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Protostome Animals mouth forms from blastopore
(most invertebrates)
26-1 Introduction to the Animal Kingdom
Deuterostome Animals anus forms from blastopore
(echinoderms and vertebrates
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Early Embryonic Development
26-1 Introduction to the Animal Kingdom

• Endoderm inner
• Mesoderm middle
• Ectoderm outer

Cells differentiate into 3 germ layers
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Early Embryonic Development
26-1 Introduction to the Animal Kingdom
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2. Body Symmetry
26-1 Introduction to the Animal Kingdom

• Ability to divide a body into 2 equal halves

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2. Body Symmetry
26-1 Introduction to the Animal Kingdom

• Planes of symmetry Dorsovental Axis
  (Sagittal Plane)

• Cuts the body into right and left sides

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2. Body Symmetry
26-1 Introduction to the Animal Kingdom

• Planes of symmetry Transverse Axis

• Produces a cross-section of the body
• Divides the body into Anterior and Posterior
  regions

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2. Body Symmetry
26-1 Introduction to the Animal Kingdom

• Regions of the body

Posterior Rear End
Dorsal Upper
Anterior Front
Ventral Lower
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Trends of Evolution
26-1 Introduction to the Animal Kingdom

• There are two more characteristics that most
  animals share in addition to Cell
  Specialization and Body Symmetry
• 3. Cephalization
• 4. Body Cavity Formation

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3. Cephalization
26-1 Introduction to the Animal Kingdom

• Refers to the characteristic that more sense
  organs and nerve cells are located at the
  anterior part of the body than anywhere else

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3. Cephalization
26-1 Introduction to the Animal Kingdom

• Allows animals to respond quicker and in more
  complex ways to stimuli

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4. Body Cavity Formation
26-1 Introduction to the Animal Kingdom

• Body cavity is a fluid-filled space that contains
  the organs

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4. Body Cavity Formation
26-1 Introduction to the Animal Kingdom

• This allows space for internal organs to keep
  their shape and to grow properly

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Evolutionary Relationships
26-1 Introduction to the Animal Kingdom
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26-2 SPONGES
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Sponges
26-2 Sponges

• Phylum Porifera
• Have tiny openings, or pores,
  all over their bodies
• Sessile they live their entire life
  attached to a single spot
• They are animals. Why?

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Sponges are Animals
26-2 Sponges
Click Picture To Watch a 3 Minute Sponge From and
Function Video

• Multicellular
• Heterotrophic
• No cell walls
• Contain a few specialized cells

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Form and Function in Sponges
26-2 Sponges

• Have nothing resembling a mouth or gut
• Have no tissues or organ systems
• Simple functions are carried out by a few
  specialized cells

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Asymmetrical
26-2 Sponges

• Have no front or back ends, no left and right
  sides
• A large, cylindrical water pump
• The body forms a wall around a large central
  cavity through which water flows continually

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26-2 Sponges
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Specialized Cells
26-2 Sponges

• Choanocytes
• Specialized cells that use flagella to move a
  steady current of water through the sponge
• Osculum
• Water leaves through the large hole
  at the top of the sponge

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Choanocytes
26-2 Sponges

• Specialized cells that use flagella to move a
  steady current of water through the sponge
• Filters several thousand liters/day

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Osculum
26-2 Sponges

• A large hole at the top of the sponge, through
  which water exits
• The movement of water provides a simple mechanism
  for feeding, respiration, circulation and
  excretion

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Specialized Cells
26-2 Sponges

• spicule
• is a spike-shaped structure made of chalklike
  calcium carbonate or glasslike silica
• archaeocytes
• are specialized cells that move around within the
  walls of the sponge and make spicules.
• spongin
• network of flexible protein fibers that make up
  the internal skeleton of a sponge.

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Simple Skeleton
26-2 Sponges

• Spicule a spike-shaped structure made of
  chalk-like calcium carbonate or glasslike
  silica in hard sponges
• Archaeocytes specialized cells that make
  spicules

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26-2 Sponges
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Sponge Feeding
26-2 Sponges
Click Picture To Watch a 5 Minute Sponge Filter
Feeding Video

• Filter feeders
• Sift microscopic
  food from the water
• Particles are engulfed by
  choanocytes that line the body cavity

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Respiration, Circulation, Excretion
26-2 Sponges

• Rely on the movement of water through their
  bodies to carry out body functions
• As water moves through the cavity
• Oxygen dissolved in the water diffuses into the
  surrounding cells
• Carbon dioxide and other wastes, diffuse into the
  water and are carried away

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Response
26-2 Sponges

• No nervous system
• Many sponges protect themselves by producing
  toxins that make them unpalatable or poisonous to
  potential predators

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Reproduction
26-2 Sponges
Click Picture To Watch A 2 Minute Sponge
Reproduction Video

• Sexually or asexually
• A single spore forms both eggs and sperm usually
  at different times

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Sexual Reproduction
26-2 Sponges

• Internal fertilization Eggs are fertilized
  inside the sponges body
• Sperm are released from one sponge and carried by
  currents to the pores of another sponge

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Asexual Reproduction
26-2 Sponges

• Budding
• Gemmules groups of archaeocytes surrounded by
  spicules

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Ecology of Sponges
26-2 Sponges

• Ideal habitats for marine animals such as snails,
  sea stars, sea cucumbers, and shrimp
• Mutually beneficial relationships with bacteria,
  algae and plant-like protists
• Many are green due to these organisms living in
  their tissues

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Ecology of Sponges
26-2 Sponges

• Attached to the seafloor and may receive little
  sunlight
• Some have spicules that look like cross-shaped
  antennae
• Like a lens or magnifying glass, they focus and
  direct incoming sunlight

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26-3 CNIDARIANS
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Cnidarians
26-3 Cnidarians

• Phylum Cnidaria
• Hydras, jellies,
  sea
  anemones, and corals
• Soft-bodied
• Carnivorous
• Stinging tentacles arranged in circles around
  their mouths
• Simplest animals to have body symmetry and
  specialized cells

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Cnidocytes
26-3 Cnidarians

• Stinging cells that are located on their
  tentacles
• Used for defense and to capture prey

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Nematocyst
26-3 Cnidarians

• A poison-filled, stinging structure that contains
  a tightly coiled dart
• Found within cnidocytes

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26-3 Cnidarians
Click Picture To Watch a 2 Minute Feeding Anemone
Video
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26-3 Cnidarians
Click Picture To Watch a 3 Minute Stinging
Jellyfish Video
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Form and Function in Cnidarians
26-3 Cnidarians

• Only a few cells thick
• Simple body systems
• Most of their responses to the environment are
  carried out by specialized cells and tissues

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Radially Symmetrical
26-3 Cnidarians

• Central mouth surrounded by numerous tentacles
  that extend outward from the body
• Life cycles includes a polyp and a medusa stage

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Body Plan
26-3 Cnidarians

• Polyp cylindrical body with arm-like tentacles
  mouth points upward
• Medusa motile, bell-shaped body mouth on the
  bottom

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26-3 Cnidarians
Phylum Cnidarian
Epidermis Mesoglea Gastroderm
Medusa
Polyp
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Feeding
26-3 Cnidarians

• Polyps and medusas have a body wall that
  surrounds an internal space the gastrovascular
  cavity
• Gastrovascular cavity a digestive chamber with
  one opening
• Food enters and wastes leave the body

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Respiration, Circulation, Excretion
26-3 Cnidarians

• Following digestion, nutrients are usually
  transported throughout the body by diffusion
• Respire and
  eliminate wastes
  by diffusion
  through body walls

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Response
26-3 Cnidarians

• Specialized sensory cells are used to gather
  information from the environment
• Nerve net loosely organized network of nerve
  cells that together allow cnidarians to detect
  stimuli
• Distributed uniformly throughout the body in most
  species
• In some species it is concentrated around the
  mouth or in rings around the body

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26-3 Cnidarians
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Response
26-3 Cnidarians

• Statocysts groups of sensory cells that help
  determine the direction of gravity
• Ocelli eyespots made of cells that detect light

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Movement
26-3 Cnidarians

• Hydrostatic skeleton a layer of circular muscles
  and a layer of longitudinal muscles that enable
  cnidarians to move

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Reproduction Sexually and Asexually
26-3 Cnidarians

• Polyps can reproduce asexually by budding
• External sexual reproduction
• The sexes are separate-each individual is either
  male or female
• Both egg and sperm are released into the water

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26-3 Cnidarians
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26-3 Cnidarians
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26-3 Cnidarians
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Groups of Cnidarians
26-3 Cnidarians

• Jellies (formerly jellyfishes)
• Hydras and their relatives
• Sea anemones
• Corals

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26-3 Cnidarians
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Groups of Cnidarians
26-3 Cnidarians

• Class Scyphozoa cup animal
• Jellyfish

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Classes of Cnidarians Class Scyphozoa
26-3 Cnidarians

• Spend most of their lives as medusa
• The polyp form is limited to a larva stage

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Classes of Cnidarians Class Scyphozoa
26-3 Cnidarians

• The largest jellyfish ever found is 4 meters in
  diameter with tentacles more than 30 meters in
  length
• Most species are harmless, many can cause servere
  allergic reactions/even kill people

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26-3 Cnidarians
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26-3 Cnidarians
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Groups of Cnidarians
26-3 Cnidarians

• Class Hydrozoa Hydras Portuguese Man of War

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Classes of Cnidarians Class Hydrozoa
26-3 Cnidarians

• The polyps of most hydrozoans grow in branching
  colonies that sometimes extend more than a meter.
• Within a colony, the polyps are specialized to
  perform different functions.
• EX One polyp forms a balloon-like float
  that keeps the entire colony afloat
• Portuguese Man of War

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Classes of Cnidarians Class Hydrozoa
26-3 Cnidarians

• Most common in freshwater hydrozoan is a hydra
• Lack medusa stage (solitary polyp)
• Reproduce sexually (producing eggs and sperm in
  the body wall) and
  asexually (budding)
• a few species
  are hermaphroditic

Click Picture To Watch a 2 Minute Hydra Budding
Video
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26-3 Cnidarians
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Groups of Cnidarians
26-3 Cnidarians

• Class Anthozoa flower animal
• Sea Anemones and Corals

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Classes of Cnidarians Class Anthozoa
26-3 Cnidarians

• Grow only as polyps / no medusa stage
• Central body that is surrounded by tentacles
• Many species are colonial (composed of many
  individual polyps)

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Classes of Cnidarians Class Anthozoa
26-3 Cnidarians

• Corals and sea anemones reproduce sexually by
  producing free swimming larvae
• The free swimming larvae attach to rocks and then
  form polyps
• Also can reproduce by budding

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Classes of Cnidarians Class Anthozoa
26-3 Cnidarians

• Forming Coral Reefs
• Formed when hard coral from layers of skeleton
  (CaCO3)
• Algae forms a sybiotic relationship with coral

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26-3 Cnidarians
Click Picture To Watch a 1 Minute Coral Budding
Video
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26-3 Cnidarians
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Ecology of Corals
26-3 Cnidarians

• The worldwide distribution is determined by
• Temperature
• Water depth
• Light intensity
• Many suffer from human activity
• Coral bleaching has become common
• Global warming may add to the problem

Click Picture To Watch a 5 Minute Coral Spawn
Video