Download Lecture 13a - BlakeMathys.com

4/7/2011
Invertebrates
• 95% of all known animals
• Mammals, birds, reptiles, amphibians, and fishes are a small part of animal diversity
Invertebrate Diversity
Invertebrate Diversity
Phylum Placozoa
• One Species: Trichoplax adhaerens
• A few thousand cells, no organs
• Mostly asexual reproduction
“Sponges”
• 2 Phyla: Calcarea and Silicea
• Filter Feeders
• No true tissues
– Cell Types:
Choanocytes (collar cells): Feeding cells, with flagella
Amoebocytes: digestion, food transport, skeletal production
2 cell layer, separated by gelatinous mesohyl
“Sponges”
• 2 Phyla: Calcarea and Silicea
• No true tissues
• Suspension Feeders
“Sponges”
• Reproduction
– Hermaphroditic (both sperm and eggs)
– Sequential
– Gametes from choanocytes
Gametes from choanocytes or amoebocytes
or amoebocytes
• Sperm released, carried into other individuals
• Zygote develops into flagellated, swimming larva
• Some produce antibiotics
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Phylum Cnidaria
Phylum Ctenophora (Comb Jellies)
• True Tissues: Diploblastic
• Radial Symmetry
• 8 “combs” of cilia
Phylum Cnidaria
• True Tissues: Diploblastic
• Radial Symmetry
• Two basic body plans
Phylum Cnidaria – 4 Classes
• Carnivorous
• Cnidocytes
Cubozoa
– Contain cnidae
• exploding organelles
– Some specialized into nematocysts
• Venomous
Hydrozoa
• Mostly Marine
Scyphozoa
Anthozoa
Phylum Cnidaria – 4 Classes
Phylum Cnidaria – Reproduction
• Cubozoa Defenses
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Phylum Acoela
• Bilateral symmetry
• Simple flatworms
• Formerly placed with Platyhelminthes
with Platyhelminthes
Phylum Platyhelminthes
• Flatworms; Acoelomate
– Turbellarians: Free Living
Phylum Platyhelminthes
• Parasitic Flatworms
– Monogeneans, Trematodes, Tapeworms
– Mimic surface proteins
Blood fluke
Blood fluke
Lophotrochozoa
• Triploblastic
• Bilateral Symmetry
• 18 phyla
Phylum Platyhelminthes
• Parasitic Flatworms
– Monogeneans, Trematodes, Tapeworms
– External parasites of fish
Phylum Platyhelminthes
• Parasitic Flatworms
– Monogeneans, Trematodes, Tapeworms
Live in intestine: no mouth
Up to 0
Up to 20m
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Phylum Rotifera
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Small (max 2mm)
2 opening digestive tract
Pseudocoelomate
Many use parthenogenesis only
Phylum Mollusca
Lophophorates
• Lophophore
• Phylum Ectoprocta
– “Bryozoans”
• Phylum Brachiopoda
• Coelomate
Phylum Mollusca
• Soft‐bodied, many secrete shell
• Coelomate
• Foot, visceral mass, mantle
– Some have mantle cavity
• Contains gills, anus, excretory pores
• Many have a radula
– Scrapes food
• Many have trochophore larva
Phylum Mollusca
• Class Polyplacophora – Chitons
– Shell w/ 8 plates
• Scrapes algae with radula
Phylum Mollusca
• Class Gastropoda – Snails, Slugs, Nudibranchs
• Torsion
– 180° twist during development
• Many eat algae or plants
– Some modified radula
for drilling or as poison dart
• Shell present in snails
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Phylum Mollusca
Phylum Mollusca
• Class Bivalvia – Oysters, Mussels, Scallops, etc.
• Shell w/ 2 halves; adductor muscles
• No radula; filter feeders
• Class Cephalopoda – Squid, Octopi, Nautili
• Active predators, fast movements
• Shell reduced/internal or absent
– Except nautilus
Video
• Closed circulatory system
• Tentacles and beak
• Good eyes, smart
Phylum Mollusca
• Class Cephalopoda – Squid, Octopi, Nautili
– Can get to enormous size
– Move by shooting water jets through
water jets through excurrent siphon
Phylum Annelida
• Segmented Worms
• Coelomate
• Up to 3m
Phylum Annelida
• Oligochaetes – Earthworms
– Few bristles (made of chitin)
– Extract nutrients from soil
• Polychaetes
P l h t – Many bristles
M
b i tl
– Mainly marine
• Leeches
– Predators and parasites
Phylum Annelida
• Clitellum
– Secretes mucus, which picks up eggs and sperm
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• Some can reproduce by fragmentation
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