The Animal Kingdom
Unifying Animal Concepts:
• 1. They are classified according to body
plan, symmetry, number of germ layers, &
level of organization.
• 2. There is an increase in complexity when
groups are arranged in order from first
evolved to most recent.
• 3. Animals are adapted to their way of life.
(Active vs. inactive, aquatic vs. terrestrial)
Animal Characteristics
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Heterotrophic- have to take in food
Generally have an active lifestyle
Multicellular
Organized cells into tissues, tissues into
organs
2 Groups of Animals
• 1. Invertebrates: lack a dorsal backbone
2. Vertebrates: have a backbone
made up of vertebrae
Animal Body Plans
• 1. Sac Plan: One opening for food intake
and waste excretion.
• 2. Tube within a tube: one entrance for
food, another exit for waste.
Animal Symmetry
• Asymmetry: No Particular Symmetry
• Radial Symmetry: Animal is organized
circularly (like a wheel). Tend to be sessile.
Why?
– Can reach food in all directions around them!
• Bilateral Symmetry: definate left and right
halves.
Animal Germ Layers
• Ectoderm: Outer
• Endoderm: Inner
These 2 form tissue level organization.
• Mesoderm: Middle
Animals with all 3 have organ level
organization.
Internal Body Cavities
• Acoelomate: NO open space in which
internal organs are located
• Coelomate: have a true Coelom - open
space
Primitive Invertebrates
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Sponges
Cnidarians
Flatworms
Roundworms
Classification
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Common Name: Sponge
Scientific Name: Grantia
Phylum: Porifera
Class: Calcarea
Other: 5,000 species; 150 species live in
fresh water
SPONGES
• Phylum: Porifera “Pore Bearer”
• Body Plan: Sac; 2 cell layers with jellylike
mesophyll in between
• Body Cavity: Acoelomate, hollow cylinder
• Symmetry: Asymmetry
• Cell Specialization: Collar Cells
(Choanocytes) & Amoebocytes; cell
recognition
• Other: most are marine, abundant in warm
coastal waters
Sponge Life Processes
• Absorption: Collar cells with tiny flagella
draw water & food (plankton) into pores,
digested by food vacuoles in cells
• Feeding: Sessile filter feeders
• Digestion: food vacuoles in cells
• Respiration: Water flowing through pores
Sponge Life Processes
• Circulation: Amoebocyte cells transport
nutrients from cell to cell, physically move
(crawl) within the body wall
• Excretion: Carbon dioxide & waste diffuse
into water; Osculum = large opening on the
top
• Secretion: Amoebocytes produce spicules
and sex cells
Electron Microscope
Spicules
Light Microscope
Sponge Life Processes
• Response: None, no nervous system
• Movement: Adult = none; Larvae =
ciliated and free swimming
• Reproduction: Hermaphrodite; Sexual fertilization to form a zygote in the water
(NO self fertilization!) = Ciliated Larvae
Asexual - budding (gemmule formation
during harsh conditions) & regeneration
Sponge Life Processes
• Support: Spicules = calcium carbonate &
silica; very hard. Spongin = Protein; soft
Ecological Relationships
• Mostly Marine
• Food for snails, fish, starfish
Body Systems Compared to
Humans
• Fertilization: Separate sperm and egg cells
Sponge Diagram
Question:
• How much deeper would the oceans be if
sponges didn’t live there?
• Sponges drink about 64 glasses of water a
day and some species filter almost 20,000
times their volume in a day.
• Worlds largest Sponge: Barrel Shaped
Loggerhead Sponge = 4 ft. high; 3 ft. diam.
Found in the West Indies & off of Florida
• Largest ever found = Wool Sponge 6 ft. in
circumference
• Deepest Sponges = found at depths of up to
18,500 ft.
• In 1994, a “predatory” sponge was
discovered in a Mediterranean cave
near Marseilles, France, this sponge
actually covers the prey and then
consumes it.
• If part of a sponge breaks off, it can
actually become a separate, thriving
sponge.