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Animal Diversity
Figure 32.4 A traditional view of animal diversity based on body-plan grades
Figure 32.8 Animal phylogeny based on sequencing of SSU-rRNA
The diversification of animals
through evolution helps us to
understand what an animal is.
• “All models are false, but some are useful”
George Box, Professor of Statistics,
University of Wisconsin
Figure 32.13x Burgess Shale fossils
Burgess shale
• http://www.youtube.com/watch?v=O8UXlc
gzcEA
• Anomalocaris 1 meter long predator
• http://www.youtube.com/watch?v=iEh6ufo
p6tE
Opabinia
• five stalked eyes; a backward-facing mouth under the head; and a long, flexible, hose-like proboscis which extended from under the front of the head and ended in a "claw" fringed with spines.
Figure 32.13 A sample of some of the animals that evolved during the Cambrian
explosion
Figure 33.1 Review of animal phylogeny
Choanoflagellate colony
Phylum Porifera
• Sponges
• “colony” of flagellated cells (choanocytes)
• Porocytes on surface
• individual cells can potentially regenerate
into a new individual
• No true tissues, no symmetry
• Spicules, spongin
Figure 33.3 Anatomy of a sponge
Radial
Figure 32.5 Body symmetry
Phylum Cnidaria
• Hydras, jellyfish, sea anemones, corals
• True tissues, nervous system, muscles,
sensory organs, digestive system
• generally two tissue layers: gastrodermis,
epidermis
• gastrovascular cavity
• stinging cells
• Radiata
Figure 33.4 Polyp and medusa forms of cnidarians
Figure 33.5 A cnidocyte of a hydra
Discharged cnidocyte
• http://www.youtube.com/watch?v=KHBhW
VKOXt0
Cnidarians - Medusa forms
The Irukandji
(Carukua barnesi)
• 1 inch diameter
• Australia
• Can kill human in a
few days
• Microscopic video footage of jellyfish nematocysts firing. The video was created by the TASRU (Tropical Australian Stinger Research Unit) of James Cook University. The video shows nematocysts along a section of tentacle from Carukia barnesi (Irukandji jellyfish) discharging after artificial stimulation. The image has been filmed through a microscope and is magnified about 400 times.
• http://www.youtube.com/watch?v=6zJiBc_N1Zk
Jellyfish lake Palau • http://www.youtube.com/watch?v=GTXinF8Z
VCo
• The golden jellyfish Mastigias cf. papua
etpisoni
Giant jellyfish
• http://www.youtube.com/watch?v=HqfCm5
8SB6Y
Cnidarians – Polyp forms
Sea anemone – Anthopleura
tidepools Pacific Coast
Corals – see also “google street
view”
Cnidaria
• Stomphia didemon
• Orange swimming anemone
• 80-160 m depth
• Usually attached to horse mussels around sandy substrates
• http://www.youtube.com/watch?v=Dm98n3908QM
Phylum Ctenophora • Comb jellies
• comblike ciliary plates for propulsion, no
stinging cells (sticky tentacles instead)
• True tissues, nervous system, muscles,
sensory organs, digestive system
• 2-3 tissue layers; gastrovascular cavity
• Radiata
Diverse body shapes despite
being a relatively small phylum
Bilateral
Figure 32.6 Body plans of the bilateria
Phylum Platyhelminthes
• Flatworms
• dorsoventrally flattened
• no segmentation
• gastrovascular cavity
• bilateral, no coelom, protostome
Figure 33.10 Anatomy of a planarian
Figure 33.12 Anatomy of a tapeworm
http://www.youtube.com/watch?
v=HOaZCkA8Zvk
Phylum Nematoda
• Roundworms
• unsegmented
• no circulatory system
• bilateral, pseudocoelomate, protostome
Figure 33.25a Free-living nematode
Lophophorates - several phyla
• Bryozoans, lampshells (brachiopods)
• bilateral, coelomate, protostome
Figure 33.14 Lophophorates: Bryozoan (left), brachiopod (right)
Phylum Mollusca
• Clams, snails, squids
• foot, visceral mass, mantle
• bilateral, coelomate, protostome
Table 33.3 Major Classes of Phylum Mollusca
Phylum Mollusca
Class Gastropoda
Figure 33.16 Basic body plan of mollusks
Mollusca
• Euspira lewisii
• Moon snail
• one of the largest to be found intertidally in the Northwest
• It does not usually stay inside the shell long because it cannot breathe.
• It crawls across sandflats and mudflats with its huge foot partly extended in front of the shell like a snowplow, pushing through the sediments in search of clams.
Figure 33.18 The results of torsion in a gastropod
Phylum Mollusca
Class Bivalvia
Figure 33.21 Anatomy of a clam
Freshwater mussel: Lampsilis
reeveiana
http://unionid.missouristate.edu/gallery/L_reeveiana/Reeviana.htm
Snuffbox mussel (Epioblasma
triquetra) and logperch host
http://www.unionid.missouristate.edu/gallery/Epioblasma/default.htm
Phylum Mollusca
Class Cephalopoda
Humboldt squid
Architeuthis dux
Vampyroteuthis infernalis • Vampire squid from “hell”
http://www.youtube.com/watch?v=S3CJIKKSUpg
• No ink production, produces bioluminescent mucus cloud
• Black surface
• Lives in the oxygen minimum zone
Hawaiian bobtail squid
• Houses bioluminescent Vibrio bacteria in a “crypt”. Uses the light for counterillumination when they hunt at night
• There is a reflector and lens as part of the light organ
Phylum Annelida
• Segmented worms
• bilateral, coelomate, protostome
Figure 33.23 Anatomy of an earthworm
Giant palouse earthworm Driloleirus
americanus
• The white, lily-scented denizen of the region’s fertile, deep soils reportedly can grow to 3 feet long
• Thought to be extinct
• Specimen found by UI researcher in 2006
Table 33.4 Classes of Phylum Annelida
Phylum Arthropoda
• Crustaceans, insects, spiders
• segmented body, jointed appendages,
exoskeleton
• bilateral, coelomate, protostome
Figure 33.26 External anatomy of an arthropod
Interesting arthropods
• Pistol shrimp
http://www.youtube.com/watch?v=eKPrGx
B1Kzc
Isopods
• Look like pillbugs, normally small
• http://www.youtube.com/watch?v=xeOSXt
BCY30
Mantis shrimp - Stomatopods
• Second leg is a spear or club, special hard
chitin
• http://www.youtube.com/watch?v=pgvsQ6o
NZyo
Figure 33.30b Spider anatomy
Figure 33.33 Anatomy of a grasshopper, an insect
Bilateral
Deuterostomes
Figure 32.7 A comparison of early development in protostomes and deuterostomes
Phylum Echinodermata
• Starfish, sea urchins
• Endoskeleton, water vascular system, tube
feet, pedicellaria, spines, regeneration
capability
• bilateral, coelomate, deuterostome
Figure 33.38 Anatomy of a sea star
Echinodermata - starfish
• Pycnopodia helianthoides
• Sunflower star
• Voracious predator
• http://www.youtube.com/watch?v=Tys0w3CgApQ
• http://www.youtube.com/watch?v=ALaMoS_vvNE
Echinodermata - urchin
• Strongylocentrotus franciscanus
• Red sea urchin – eats kelps, jaw like structure
• these urchins live over 100 years, and found some near Vancouver Island that may be 200 years old
• A prime food for sea otters.
• http://www.youtube.com/watch?v=MXQF7dhVDSY&feature=related
• http://www.youtube.com/watch?v=b44_-bxr07w
Echinoderms
• Sea cucumber – radial symmetry, forms
cylinder shape
Phylum Chordata
• Lancelets, tunicates, vertebrates
• notochord, nerve cord
• bilateral, coelomate, deuterostome
Figure 34.2 Chordate characteristics
Figure 34.4a Subphylum Cephalochordata: lancelet anatomy
Figure 34.3 Subphylum Urochordata: a tunicate
Table 33.7 Animal phyla