Download porifera cnidaria

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
Animal Diversity
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
Evolutionary Tree
deuterostome
development
Chordates
Echinoderms
bilateral symmetry
3 tissue layers
body cavity
molting of
cuticle
tissue
layers
Arthropods
Annelids
trochophore
Molluscs
multicellularity
ancestral protist
Ttrochozoa
protostome
development
Protostomia
Bilateria
Roundworms
Ecdysozoa
common ancestor
Deuterostomia
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Flatworms
Cnidarians
radial symmetry
2 tissue layers
Sponges
Radiata
Rotifers
30.1 Evolutionary Trends Among Animals
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dorsal
ventral
radial symmetry
posterior
anterior
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
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
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:
1.
2.
3.
Cleavage
Fate of blastopore
Coelom formation
• Deuterstomes – echinoderms and chorodates
• Protostomes
•
•
Ecdysozoa – roundworms and arthropods
Trochozoa – have trochophore larvae
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Deuterostomes
Cleavage
Protostomes
top view
side view
top view
Cleavage is spiral and
determinate.
side view
Cleavage is radial and
indeterminate.
Protostomes
Deuterostomes
mouth
blastopore
anus
primitive gut
anus
primitive gut
mouth
Fate of blastopore
blastopore
Blastopore becomes the anus.
Protostomes
Deuterostomes
Coelom formation
Blastopore becomes mouth.
mesoderm
gut
Coelom forms by a
splitting of the mesoderm.
mesoderm
gut
Coelom forms by an
outpocketing of primitive gut.
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
Simple Sponge Anatomy
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a. Yellow tube spoge,Aplysina fistularis
© Andrew J. Martinez/Photo Researchers, Inc
Simple Sponge Anatomy
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osculum
sponge wall
H2O out
spicule
pore
H2O in
through
pores
amoebocyte
epidermal
cell
central
cavity
c.
collar
d.
collar cell (choanocyte)
nucleus amoebocyte
flagellum
b. Sponge organization
Simple Sponge Anatomy
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osculum
sponge wall
H2O out
spicule
pore
H2O in
through
pores
amoebocyte
epidermal
cell
central
cavity
c.
collar
nucleus amoebocyte
flagellum
a. Yellow tube spoge,Aplysina fistularis
b. Sponge organization
a: © Andrew J. Martinez/Photo Researchers, Inc
d.
collar cell (choanocyte)
Fig. 15-4b, p. 296
Basket Sponge
Luffa sponge
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
Cnidarian Diversity
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mouth
tentacle
gastrovascular
cavity
planula
mesoglea
zygote
Polyp
asexual
budding
fertilization
mesoglea
gastrovascular
cavity
sperm
egg
mouth
a.
tentacle
Medusa
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Fig. 30.5b
b. Sea anemone, Corynactis
© Azure Computer & Photo Services/Animals Animals
Fig. 30.5c
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c. Cup coral, Tubastrea
© Ron & Valerie Taylor/Bruce Coleman, Inc
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Fig. 30.5d
d. Portuguese man-of-war, Physalia
© Runk/Schoenberger/Grant Heilman Photography
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Fig. 30.5e
e. Jellyfish, Aurelia
© © Amos Nachoum/Corbis
Giant Jelly Fish
Coral Reef
Coral spawning
Portuguese Man of War
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
Anatomy of Hydra
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bud
© CABISCO/Visuals Unlimited
Anatomy of Hydra
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mouth
tentacle
gastrodermis
gastrovascular
cavity
epidermis
Anatomy of Hydra
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coiled thread
trigger
cnidocyte
before discharge
of nematocyst
lid
nematocyst
filament
cnidocyte
after discharge
of nematocyst
spines
barb