Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
PowerPoint® Lecture Presentations for
Biology Eighth Edition
Neil Campbell and Jane Reece
Lectures by Chris Romero, updated by Erin Barley with contributions from Joan Sharp
Chapter 33Chapter 33
Invertebrates
Fig. 33-1
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Overview: Life Without a Backbone
• Invertebrates are animals that lack a backbone
• They account for 95% of known animal species
Fig. 33-2
ANCESTRALPROTIST
Commonancestor ofall animals
Calcareaand Silicea
Eu
me
tazo
a
Bila
teria
Cnidaria
Mollusca/Annelida
Nematoda/Arthropoda
Chordata/Echinodermata
Sponges/“Porifera”
Fig. 33-3a
A sponge A jelly
Phylum Choanocytes Phylum Cnidaria(“Porifera”)
Fig. 33-3a
Phylum Platyhelminthes Phylum Rotifera
A marine flatworm A rotifer (LM)
Fig. 33-3m
An octopus
Phylum Mollusca Phylum Annelida
A marine annelid
Fig. 33-3s
A roundworm A scorpion(an arachnid)
Phylum Nematoda Phylum Arthropoda
Fig. 33-3v
A sea urchin
Phylum Echinodermata Phylum Chordata
A tunicate
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Concept 33.1: Sponges are basal animals that lack true tissues
• Sponges are sedentary, filter feeding animals from the phyla Calcarea and Silicea “Porifera”
• They live in both fresh and marine waters
• Sponges lack true tissues and organs
• Possess collar cells to propel water through the body and strain food particles.
• Food digested intracellularly by amebocytes
• Most asymmetrical
• http://www.youtube.com/watch?v=RmPTM965-1c&feature=related (sponge feeding)
Fig. 33-4
Azure vase sponge (Callyspongiaplicifera)
Spongocoel
Osculum
Pore
Epidermis Waterflow
Mesohyl
Choanocyte
Flagellum
Collar
Food particlesin mucus
Choanocyte
AmoebocytePhagocytosis offood particles
Spicules
Amoebocytes
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Concept 33.2: Cnidarians are an ancient phylum of eumetazoans
• All animals except sponges and a few other groups are animals with true tissues (Eumetazoa)
• Phylum Cnidaria: jellies, corals, sea anemones
• Radial symmetrical carnivores
• Diplobastic - Two body layers: ectoderm & endoderm
• Possess gastrovascular cavity (not a complete tube) and nematocysts
• There are two variations on the body plan: the sessile polyp and motile medusa
Fig. 33-5
PolypMouth/anus
Bodystalk
Tentacle
Gastrovascularcavity
Gastrodermis
Mesoglea
Epidermis
TentacleMouth/anus
Medusa
Fig. 33-6
Tentacle
Nematocyst
“Trigger”
Cuticleof prey
Threaddischarges
Thread(coiled)
Cnidocyte
Thread
Fig. 33-7
(a) Colonial polyps (class Hydrozoa)
(b) Jellies (class Scyphozoa)
Sea wasp (classCubozoa)
(d) Sea anemone (class Anthozoa)
(c)
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Conceptual Summary
• Sponges and cnidarians are almost entirely marine and are considered primitive because they do not possess three body layers nor true organs
• http://www.youtube.com/watch?v=zkF_1r6ll54&feature=related (hydra eating)
• http://www.youtube.com/watch?v=a5oHMjGqjyo (budding in hydra)
Fig. 33-8-1
Feedingpolyp
Reproductivepolyp
Medusabud
Medusa
ASEXUALREPRODUCTION(BUDDING)Portion of
a colonyof polyps
1 m
m
Key
Haploid (n)Diploid (2n)
Fig. 33-8-2
Feedingpolyp
Reproductivepolyp
Medusabud
Medusa
ASEXUALREPRODUCTION(BUDDING)Portion of
a colonyof polyps
1 m
m
Key
Haploid (n)Diploid (2n)
Gonad
SEXUALREPRODUCTION
MEIOSIS
FERTILIZATION
Egg Sperm
Zygote
Fig. 33-8-3
Feedingpolyp
Reproductivepolyp
Medusabud
Medusa
ASEXUALREPRODUCTION(BUDDING)Portion of
a colonyof polyps
1 m
m
Key
Haploid (n)Diploid (2n)
Gonad
SEXUALREPRODUCTION
MEIOSIS
FERTILIZATION
Egg Sperm
Zygote
Planula(larva)
Developingpolyp
Maturepolyp
Medusa producedby asexual budding
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Platyhelminthes: Flatworms
• Acoelomates – solid body, without a body cavity
• Bilateral symmetry and beginnings of cephalization
• Development of true organs, tripbloblastic (three body layers); ectoderm, endoderm, mesoderm
• No coelom (body cavity)
• Digestibe tract incomplete – only one opening that braches throughout the body to distribute food
• http://www.youtube.com/watch?v=5fx-YgcP8Gg (flatworm mating behavior – Rated R)
Fig. 33-9
Fig. 33-10
Pharynx
Gastrovascularcavity
Mouth
Eyespots
Ganglia Ventral nerve cords
Fig. 33-12
Proglottids withreproductive structures
Hooks
Sucker
Scolex
200 µm
• Tapeworms are parasites of vertebrates and lack a digestive system• Tapeworms absorb nutrients from the host’s intestine• Fertilized eggs, produced by sexual reproduction, leave the host’s
body in feces
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Rotifera
• Pseudocoelomates – body cavity between digestibe tract and body wall is not completely lined by mesoderm
• Rotifers have an alimentary canal, a digestive tube with a separate mouth and anus (complete digestive tract) that lies within a fluid-filled pseudocoelom
• http://www.youtube.com/watch?v=PALgTXQOqQo&feature=related (rotifer feeding)
Fig. 33-13
Jaws Crownof cilia
AnusStomach 0.1 mm
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Nematoda: Roundworms
• Nematodes, or roundworms, are found in most aquatic habitats, in the soil, in moist tissues of plants, and in body fluids and tissues of animals
• Pseudocoelomates
• They have an alimentary canal, but lack a circulatory system
• Reproduction in nematodes is usually sexual, by internal fertilization
• http://video.google.com/videoplay?docid=-2019570087567872766# (C. elegans crawling)
Fig. 33-25
25 µm
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Conceptual Summary
• Flatworms and roundworms have bilateral symmetry, the beginnings of cephalization, and three body layers with well developed tissues and organs. Phyla include many important parasites of humans.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
• All of the animals that we cover from this point on are coelomates – body cavity (coelom) is completely lined by mesoderm. Groups are divided as protostomes or deuterostomes
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Mollusca
• Phylum Mollusca includes snails and slugs, oysters and clams, and octopuses and squids
• Basic body plan of muscular head-food, with body on top a loosely covered mantle which may secrete a shell
• Gastropods have a well defined head, tentacles and elongated flattened foot
• Marine and freshwater filter feeders have a body flattened between two valves of a hinged she. Bivalvia
• Cephalopods are on the the most advanced invertebrate groups (octopus, squid, nautilus)
• Protostomes
Fig. 33-15
Nephridium Visceral mass
Coelom
Mantle
Mantlecavity
Heart
Intestine
Gonads
Stomach
Shell
Radula
MouthEsophagusNerve
cordsFoot
Gill
Anus
Mouth
Radula
Fig. 33-16
Fig. 33-17
(a) A land snail
(b) A sea slug
Fig. 33-19
Fig. 33-20
Mouth
Digestivegland
MantleHinge area
Gut
Coelom
Heart Adductormuscle
Anus
Excurrentsiphon
Waterflow
IncurrentsiphonGillGonad
Mantlecavity
Foot
Palp
Shell
Fig. 33-21
Octopus
Squid
Chambered nautilus
http://www.youtube.com/watch?v=OBg0k9GbHiw&feature=fvwrel (squid inking)
http://www.youtube.com/watch?v=QMFqV4SJLWg (nautilus)
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Annelida: Segmented Worms
• Possess a coelom and closed circulatory system
• Body segmented - septa
• Protostomes
Fig. 33-22
Epidermis
Circularmuscle
Longitudinalmuscle
Dorsal vessel
Chaetae
Intestine
Nephrostome
Fusednervecords
Ventralvessel
Metanephridium
Septum(partitionbetweensegments)
CoelomCuticle
Anus
Metanephridium
Crop
Intestine
Gizzard
Ventral nerve cord withsegmental gangliaBlood
vessels
Subpharyngealganglion
MouthCerebral ganglia
Pharynx
Esophagus
Clitellum
Giant Australian earthworm
Fig. 33-23
Parapodia
Fig. 33-24
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Arthropoda: (jointed foot)
• Major evolutionary advances over other invertebrate groups include exoskeleton (chitin) and jointed appendages
• Open circulatory system in which fluid called hemolymph is circulated into the spaces surrounding the tissues and organs (fig. 42.3 pg. 900)
• Main groups are arachnids (spiders, ticks), crustaceans (lobsters, crabs, shrimp, krill), and insects
• Rotostomes
Fig. 33-29
Cephalothorax
Antennae(sensoryreception) Head
Thorax
Abdomen
Swimming appendages(one pair locatedunder eachabdominal segment)
Walking legs
Mouthparts (feeding)Pincer (defense)
Fig. 33-30
Fig. 33-31
Scorpion
Dust mite
Web-building spider
50 µm
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• Arachnids have an abdomen and a cephalothorax, which has six pairs of appendages, the most anterior of which are the chelicerae
• Gas exchange in spiders occurs in respiratory organs called book lungs
• Many spiders produce silk, a liquid protein, from specialized abdominal glands
Fig. 33-32
Intestine
HeartDigestivegland
Ovary
Anus
Spinnerets
Silk gland
Gonopore(exit for eggs) Sperm
receptacle
Book lung
Chelicera Pedipalp
Poisongland
Eyes
Brain
Stomach
Fig. 33-33
Fig. 33-34
Fig. 33-35
Abdomen Thorax Head
Compound eye
Antennae
Heart
Dorsalartery Crop
Cerebral ganglion
Mouthparts
Nerve cords
Tracheal tubesOvary
Malpighiantubules
Vagina
Anus
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• Flight is one key to the great success of insects
• An animal that can fly can escape predators, find food, and disperse to new habitats much faster than organisms that can only crawl
• Many insects undergo metamorphosis during their development
• In incomplete metamorphosis, the young, called nymphs, resemble adults but are smaller and go through a series of molts until they reach full size
• Insects with complete metamorphosis have larval stages known by such names as maggot, grub, or caterpillar
• The larval stage looks entirely different from the adult stage
• http://www.youtube.com/watch?v=NnJA_BkPF_Y (butterfly metamorphosis)
Fig. 33-36
(a) Larva (caterpillar)(b) Pupa
(c) Later-stage pupa (d) Emerging
adult
(e) Adult
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• Most insects have separate males and females and reproduce sexually
• Individuals find and recognize members of their own species by bright colors, sound, or odors
• Some insects are beneficial as pollinators, while others are harmful as carriers of diseases, or pests of crops
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Crustaceans
• While arachnids and insects thrive on land, crustaceans, for the most part, have remained in marine and freshwater environments
• Crustaceans, subphylum Crustacea, typically have branched appendages that are extensively specialized for feeding and locomotion
• Most crustaceans have separate males and females
Fig. 33-38
(a) Ghost crab
(b) Krill (c) Barnacles
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Conceptual Summary
• The chitinous exoskeleton of arthropods, with its many jointed appendages modified for a variety of jobs, proved so versatile that the arthropods have undergone impressive adaptive radiation with more species and individuals than any other phylum
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Concept 33.5: Echinoderms and chordates are deuterostomes
• Sea stars and other echinoderms, phylum Echinodermata, may seem to have little in common with phylum Chordata, which includes the vertebrates
• Shared characteristics define deuterostomes (Chordates and Echinoderms)
– Radial cleavage
– Formation of the mouth at the end of the embryo opposite the blastopore
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Echinodermata: Sea urchins, sea stars and sea cucumbers
• Sea stars and most other echinoderms are slow-moving or sessile marine animals
• Deuterostomes
• Vertebrates are more closely related to echinoderms than to annelids, mollusks or arthropods based on studies of embryonic development
• Echinoderms have a unique water vascular system, a network of hydraulic canals branching into tube feet that function in locomotion, feeding, and gas exchange
• Possess a skeleton of calcium carbonate just under the skin
• Immature have bilateral symmetry, however, most adults have pentaradial symmetry
• http://www.youtube.com/watch?v=A100m5EpfFI&feature=related (sea star feeding)
Fig. 33-39
AnusStomach
Spine
Gills
Madreporite
Radialnerve
Gonads
Ampulla
Podium
Tubefeet
Radial canal
Ringcanal
Central disk
Digestive glands
Fig. 33-40a
(a) A sea star (class Asteroidea)
Fig. 33-40b
(b) A brittle star (class Ophiuroidea)
Fig. 33-40c
(c) A sea urchin (class Echinoidea)
Fig. 33-40d
(d) A feather star (class Crinoidea)
Fig. 33-40e
(e) A sea cucumber (class Holothuroidea)
Fig. 33-40f
(f) A sea daisy (class Concentricycloidea)
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Chordates
• Phylum Chordata consists of two subphyla of invertebrates as well as hagfishes and vertebrates
• Chordates share many features of embryonic development with echinoderms, but have evolved separately for at least 500 million years
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You should now be able to:
1. List the characteristics of the phylum “Porifera”
2. List the characteristics of the phylum Cnidaria that distinguish it from other animal phyla
3. List the characteristics of Platyhelminthes
5. List the characteristics of Mollusca
6. List the characteristics of Annelida
7. List the characteristics of Nematoda
9. List three features that account for the success of Arthropods
10. Describe the developmental similarities between echinoderms and chordates