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