1. 30.1 Evolutionary Trends Among Animals
Domain Eukarya, kingdom Animalia
Characteristics of Animals
Heterotrophic, acquire food by ingestion
Locomotion by means of muscles
Multicellular, high degree of cell specialization
Adult is diploid
Reproduction usually sexual, with embryo undergoing developmental stages

2. Animal Diversity

3. 30.1 Evolutionary Trends Among Animals
Invertebrates
Lack an endoskeleton of bone or cartilage
All but one animal phylum are invertebrates
Vertebrates
Have an endoskeleton of bone or cartilage

4. Evolutionary Tree deuterostome development Chordates Deuterostomia
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
common ancestor
deuterostome
development
Chordates
Deuterostomia
Echinoderms
bilateral symmetry
3 tissue layers
body cavity
molting of
cuticle
Arthropods
Ecdysozoa
tissue
layers
Roundworms
Bilateria
Annelids
protostome
development
trochophore
Protostomia
multicellularity
Molluscs
ancestral protist
Ttrochozoa
Flatworms
Rotifers
Cnidarians
Radiata
radial symmetry
2 tissue layers
Sponges

5. 30.1 Evolutionary Trends Among Animals
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dorsal
posterior
ventral
anterior
radial symmetry
bilateral symmetry
Type of Symmetry
Asymmetrical
No particular symmetry
Radial Symmetry
Circular organization, can be bisected in any plane to produce mirror images, some sessile
Bilateral Symmetry
Definite right and left halves; only a cut down the midline will produce mirror images, accompanied by cephalization

6. 30.1 Evolutionary Trends Among Animals
Level of Organization
Cellular
No true tissues; sponges
Tissue
Have ectoderm and endoderm; cnidarians like hydra
Organ
Have ectoderm, endoderm, and mesoderm; majority of animals

7. 30.1 Evolutionary Trends Among Animals
Embryonic development
Animals with three tissues layers are either
Protostomes( mouth first) or deuterstomes (anus first)differentiated by three major events:
Cleavage
Fate of blastopore
Coelom formation
Deuterstomes – echinoderms and chorodates
Protostomes
Ecdysozoa – roundworms and arthropods
Trochozoa – have trochophore larvae

8. splitting of the mesoderm. outpocketing of primitive gut.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Protostomes
Deuterostomes
Cleavage
top view
side view
top view
side view
Cleavage is spiral and
determinate.
Cleavage is radial and
indeterminate.
Protostomes
Deuterostomes
blastopore
mouth
blastopore
anus
Fate of blastopore
primitive gut
anus
primitive gut
mouth
Blastopore becomes mouth.
Blastopore becomes the anus.
Protostomes
Deuterostomes
mesoderm
mesoderm
Coelom formation
gut
gut
Coelom forms by a
splitting of the mesoderm.
Coelom forms by an
outpocketing of primitive gut.

9. 30.2 Introducing the Invertebrates
Sponges: Phylum Porifera
Saclike body with many pores
Multicellular, but lack organized tissues
Filter feeders
Asexual and Sexual Reproduction
Asexually by budding, fragmentation or gemmule formation
Hermaphroditic, usually not self-fertilizing
Choanocytes (collar cells)-trap food particles
trap food particles
Classified on the basis of their skeleton
Spicules, spongin

10. Simple Sponge Anatomy a. Yellow tube spoge,Aplysina fistularis
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
a. Yellow tube spoge,Aplysina fistularis
© Andrew J. Martinez/Photo Researchers, Inc

11. Simple Sponge Anatomy osculum sponge wall H2O out spicule pore H2O in
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
osculum
sponge wall
H2O out
spicule
pore
H2O in
through
pores
amoebocyte
epidermal
cell c.
central
cavity
collar
nucleus
amoebocyte
flagellum
b. Sponge organization d.
collar cell (choanocyte) 11

12. Simple Sponge Anatomy 12 osculum sponge wall H2O out spicule pore
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
osculum
sponge wall
H2O out
spicule
pore
H2O in
through
pores
amoebocyte
epidermal
cell c.
central
cavity
collar
nucleus
amoebocyte
flagellum
a. Yellow tube spoge,Aplysina fistularis
b. Sponge organization d.
collar cell (choanocyte)
a: © Andrew J. Martinez/Photo Researchers, Inc 12

13. Figure 15.4: Animated!
(A) Body plan of a glass sponge. Arrows indicate direction of water flow. (B) Natural bath sponge.
Fig. 15-4b, p. 296

14. Basket Sponge

15. Luffa sponge

16. 30.2 Introducing the Invertebrates
Cnidarians: Phylum Cnidaria
True Tissues with two germ layers
Tubular or bell-shaped animals with radial symmetry
All aquatic, mostly marine
Named for cnidocytes
Contains nematocyst used in prey capture
Body is two layered sac with gastrovascular cavity
Two basic body forms – polyp and medusa
Includes corals, jellyfish, and hydrozoans
Corals - polyps
Jellyfish - medusae
Hydrozoans - may have both forms

17. Cnidarian Diversity a. mouth tentacle gastro- vascular cavity planula
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mouth
tentacle
gastro-
vascular
cavity
planula
mesoglea
zygote
Polyp
asexual
budding
fertilization
mesoglea
gastrovascular
cavity
sperm
egg
mouth a.
tentacle
Medusa

18. Fig. 30.5b b. Sea anemone, Corynactis
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Fig. 30.5b
b. Sea anemone, Corynactis
© Azure Computer & Photo Services/Animals Animals

19. Fig. 30.5c c. Cup coral, Tubastrea
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
c. Cup coral, Tubastrea
© Ron & Valerie Taylor/Bruce Coleman, Inc

20. Fig. 30.5d d. Portuguese man-of-war, Physalia
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
d. Portuguese man-of-war, Physalia
© Runk/Schoenberger/Grant Heilman Photography

21. Fig. 30.5e e. Jellyfish, Aurelia
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
e. Jellyfish, Aurelia
© © Amos Nachoum/Corbis

22. Giant Jelly Fish

23. Coral Reef

24. Coral spawning

26. Portuguese Man of War

27. 30.2 Introducing the Invertebrates
Cnidarians: Phylum Cnidaria
Hydra – a representative cnidarian (Class Hydrozoa)
Freshwater, attaches to rocks and plants
Small tubular polyp, sac-like body plan with a single opening
Outer tissue layer: epidermis from ectoderm
Inner layer: gastrodermis from endoderm
Longitudinal and circular muscle fibers present
Diffuse nerve net
Digestion begins in gastrovascular cavity, completed in cells
Can reproduce sexually and asexually (budding)
Sexual reproduction
Hydra develops an ovary or testis in body wall
No medusae

28. © CABISCO/Visuals Unlimited
Anatomy of Hydra
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
bud
© CABISCO/Visuals Unlimited 28

29. Anatomy of Hydra mouth tentacle gastrodermis gastrovascular cavity
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
mouth
tentacle
gastrodermis
gastrovascular
cavity
epidermis

30. Anatomy of Hydra coiled thread trigger cnidocyte before discharge
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
coiled thread
trigger
cnidocyte
before discharge
of nematocyst
lid
nematocyst
filament
spines
cnidocyte
after discharge
of nematocyst
barb 30