Biology, Seventh Edition
Solomon • Berg • Martin
Chapter 28
The Animal Kingdom:
An Introduction to
Animal Diversity
Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Characteristics common to
most animals
•
•
•
•
Eukaryotic
Multicelleular
Heterotrophic
Specialized cells
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Characteristics common to
most animals, cont.
• Capable of locomotion at some point
• Can respond adaptively to external
stimuli
• Can reproduce sexually
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Characteristics common to
most animals, cont.
• Sexual reproduction
–Sperm and egg unite to form a zygote
–Zygote undergoes cleavage
–Multiple cell divisions result in a blastula
–Blastula undergoes gastrulation
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Advantages of life in the ocean
•
•
•
•
Relatively stable temperatures
Provide buoyancy
Provide food
Fluid and salt balances are most
easily maintained in this environment
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Disadvantages of life in the
ocean
• Currents
• Other water movements
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Disadvantages of life in fresh
water
• Less constant environment
• Less food
• Fresh water is hypotonic to tissue
fluid, osmoregulation required
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Disadvantages of terrestrial life
• Potential for dessication
• Temperature change
• Gametes and embryos must be
protected
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Animals classified according to
body plan
• Asymmetrical (most sponges)
• Radial (phylum Cnidaria)
–Biradial (sea anemones and
ctenophores)
• Bilateral (most animals)
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
Radial symmetry
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
Bilateral symmetry
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Animals classified on the basis
of tissue development
• Diploblastic
–Ectoderm
–Endoderm
• Triploblastic
–Ectoderm
–Endoderm
–Mesoderm
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Ectoderm gives rise to
• Body covering
• Nervous system
• Endoderm gives rise to
• Gut lining
• Digestive organs
• Mesoderm gives rise to
• Most other body structures
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Triploblasts classified according
to type of coelom
• Acoelomates
• Coelomates
• Pseudocoelomates
–Protostomia
–Deuerostomia
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
Acoelomate – flatworm (liver fluke)
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
Pseudocoelomate - nematode
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
Coelomate - vertebrate
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Pseudocoelomates were
formerly classified as a separate
group
• Probably not a monophyletic
group
• Probably evolved through
simplification from multiple
groups of coelomates
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Two main groups of coelomates
• Protostomia
• Deuterostomia
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Protostomia
• Spiral cleavage
–Cell divisions diagonal to polar axis,
therefore spiral arrangement of cells
• Deuterostomia
• Radial cleavage
–Cell divisions parallel or at 90°, therefore
cells directly above or below each other
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
Spiral cleavage
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
Radial cleavage
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Phylogeny has three major
clades of coelomates
• Protostomia
–Lophotrochozoa
–Ecdysozoa
• Deuterostomia
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
Five main
animal clades:
Parazoa
Radiata
Lophotrochozoa
Ecdysozoa
Deuterostomia
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• In protostomes, blastophere
develops into the mouth
• In deuterostomes, the
blastophore usually becomes
the anus
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Protostomes
• Lophotrochozoa
–Platyhelminthes
–Nemerteans
–Mollusks
–Annelids
–Lophophorate phyla
–Rotifers
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Protozomes, cont.
• Ecdysozoa
–Nematodes
–Arthropods
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Deutostomes
• Echinoderms
• Chordates
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CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Phylum Porifera
• Choanocytes: animals with flagellate
collar cells
• Sole parazoa
• Sponge body consists of
–Sac with tiny openings
–Spongocoel
–Osculum
• Cells do not form true tissues
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
A simple sponge cut
open to expose its
organization. Water
drawn through the
pores passes through
the spongocoel and
exits through the
osculum. Collar cells
trap food particles in
the stream of water
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Phylum Cnidaria
•
•
•
•
Radial symmetry
Two tissue layers
Cnidocytes (cells with nematocysts)
Gastrovascular cavity has single
opening (both mouth and anus)
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
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Biology, Seventh Edition
Gonothyraea loveni
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
Montastrea cavernosa
Chrysaora fuscescens
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Phylum Cnidaria, cont.
• Irregular, non-directional nerve nets
• Nerve nets connect sensory cells with
contractile and gland cells
• Life cycle of many cnidarians includes
–Sessile polyp stage
–Free-swimming medusastage
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Phylum Cnidaria has three main
classes
• Hydrozoa
• Scyphozoa
• Anthozoa
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Hydrozoa are usually polyps
and may be solitary or colonial
• Hydras
• Hydroids
• Portuguese man-of-war
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
Hydra, a
freshwater
hydrozoan
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Scyphozoa are generally medusae
• Jellyfish
• Anthozoa are polyps and may be
solitary or colonial; they differ from
hydrozoans in the organization of
the gastrovascular cavity
• Sea anemones
• Corals
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
• Phylum Ctenophora
• Comb jellies are fragile, luminescent
marine predators
–Biradial symmetry
–Eight rows of comb-like cilia
–Diploblastic
–Tentacles with adhesive glue cells
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Biology, Seventh Edition
CHAPTER 28 The Animal Kingdom: An Introduction to Animal Diversity
Ctenophore (comb jelly)
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