honors biology
Ch.18 Objectives
The Evolution of Invertebrate Diversity
Opening Essay
Describe the predatory and defensive strategies of the blue-ringed octopus and the mimic octopus.
Animal Evolution and Diversity
18.1 Describe the defining characteristics of animals.
18.1 Describe the general animal life cycle and the basic animal body plan.
18.2 Describe the five-stage hypothesis for the evolution of animals from protists.
18.2 Describe the Cambrian “explosion” of animal diversity and two hypotheses that have been advanced to explain its
occurrence.
18.3 Explain how a hydrostatic skeleton helps an animal keep its shape and move.
18.3–18.14 Characterize the nine animal phyla discussed in this chapter in terms of the following traits:
(a) presence or absence of true tissues
(b) no symmetry, radial symmetry, or bilateral symmetry
(c) no coelom, a pseudocoelom, or a true coelom
(d) protostomes or deuterostomes.
Invertebrate Diversity
18.5–18.14
Describe the characteristics of and distinguish between each of the following phyla:
Note several examples of each phylum
Porifera
Nematoda
Arthropoda
Cnidaria
Mollusca
Echinodermata
Platyhelminthes
Annelida
Chordata
18.10 Define segmentation, explain its functions, and note the animal phyla where it occurs.
18.11 Compare the characteristics of the four major arthropod lineages. Give examples of each.
18.12 Describe the common characteristics of insects. Describe the process and significance of complete metamorphosis.
Animal Phylogeny and Diversity Revisited
18.15 Compare the phylogenetic relationships in Figures 18.4 and 18.15, noting similarities and differences.
18.16 Explain what we have learned about the evolution of life from the study of “evo-devo.”
Key Terms
amoebocyte
annelid
anterior
arachnid
arthropod
bilateral symmetry
bilaterian
bivalve
blastula
body cavity
centipede
cephalopod
chelicerate
choanocyte
circulatory system
closed circulatory system
cnidarian
cnidocyte
coelom
complete digestive tract
complete metamorphosis
crustacean
cuticle
dorsal
dorsal, hollow nerve cord
Mrs. Loyd 
cloyd@waukee.k12.ia.us
deuterostome
echinoderm
ectoderm
endoderm
endoskeleton
eumetazoan
exoskeleton
flatworm
fluke
foot
free-living flatworm
gastropod
gastrovascular cavity
gastrula
horseshoe crab
hydrostatic skeleton
incomplete metamorphosis
ingestion
invertebrate
lancelet
larva (plural, larvae)
leech
mantle
medusa (plural, medusae)
mesoderm
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metamorphosis
millipede
mollusc
molting
nematode
notochord
open circulatory system
pharyngeal slit
polychaete
polyp
post-anal tail
posterior
protostome
pseudocoelom
radial symmetry
radula
segmentation
sessile
sponge
suspension feeder
tapeworm
tunicate
ventral
visceral mass
water vascular system
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Student Media
Animal Evolution and Diversity
Invertebrate Diversity
Activity: Characteristics of Invertebrates (18.13)
Activity: Characteristics of Chordates (18.14)
Process of Science: How Are Insect Species Identified? (18.12)
Discovery Channel Video Clip: Invertebrates (18.5)
Discovery Channel Video Clip: Leafcutter Ants (18.12)
Video: Hydra Releasing Sperm (18.6)
Video: Jelly Swimming (18.6)
Video: Thimble Jellies (18.6)
Video: Hydra Eating Daphnia (Time-Lapse) (18.6)
Video: C. elegans Crawling (18.8)
Video: C. elegans Embryo Development (Time-Lapse) (18.8)
Video: Rotifer (18.8)
Video: Nudibranchs (18.9)
Video: Earthworm Locomotion (18.10)
Video: Lobster Mouth Parts (18.11)
Video: Butterfly Emerging (18.12)
Video: Echinoderm Tube Feet (18.13)
Animal Phylogeny and Diversity Revisited
Activity: Animal Phylogenetic Tree (18.15)
Process of Science: How Do Molecular Data Fit Traditional Phylogenies? (18.15)
Mrs. Loyd 
cloyd@waukee.k12.ia.us
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1/6/11
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