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Parazoa
Eumetazoa
Bilateria
The Animal Kingdom:
The Deuterostomes
Echinodermata
Mollusca
Annilda
Deuterostomia
Arthropoda
Tardigrada
Onychophora
Protostomia
Hemichoradates
Coelomates
Pseudocoelomates
Rotifera
Nemerteans
Ctenophora
Porifera
Cnidaria
Acoelomates
Nematoda
Platyhelminthes
Radiata
Segmentation
Segmentation
Deuterostome
development
Pseudocoelom
True coelom
Radial
symmetry
Chapter 31
Protostome development
Three tissue layers (mesoderm)
Bilateral symmetry
Tissues (ectoderm and endoderm)
Multicellularity
Choanoflagellate ancestor
Fig. 29-7, p. 627
Parazoa
Eumetazoa
Bilateria
• Shared derived characters
– radial, indeterminate cleavage
– blastopore becomes anus
– larva have a loop-shaped ciliated band used for
locomotion
Echinodermata
Mollusca
Annilda
Deuterostomia
Arthropoda
Onychophora
Tardigrada
Rotifera
Protostomia
Hemichoradates
Coelomates
Pseudocoelomates
Nematoda
Nemerteans
Ctenophora
Porifera
Acoelomates
Cnidaria
Deuterostomes
Platyhelminthes
Radiata
Segmentation
Segmentation
Pseudocoelom
Deuterostome
development
True coelom
Radial
symmetry
Protostome development
Three tissue layers (mesoderm)
Bilateral symmetry
Tissues (ectoderm and endoderm)
Multicellularity
Choanoflagellate ancestor
Fig. 29-7, p. 627
Phylum Echinodermata
(bilateral ciliated larvae)
• ~7,000 (sea stars, sand dollars, urchins, sea
cucumbers
• Marine animals with
– spiny “skin”
– water vascular system
– tube feet
– Endoskeleton
– Radial symmetry – (pentaradial symmetry)
• Larvae exhibit bilateral symmetry
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Class Asteroidea
• Sea stars
– central disc with five or more arms
– use tube feet for locomotion
Class: Asteroidea
(sea stars)
• skin gills
• carnivorous (mollusks, annelids)
• metabolic wastes exits by diffusion
• water vascular system
• able to regenerate appendages
• Endoskeleton covered by thin epidermis
• coelom
Madreporite
- complete digestive system
Stone canal
• no brain - - nerve rings around mouth
• sexes separate - external fertilization
• Poorly
developed circulatory system
Ampulla
Sea Star Body Plan
Fig. 31-1, p. 669
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Parazoa
Eumetazoa
Bilateria
Phylum: Hemichordata
Echinodermata
Mollusca
Annilda
Deuterostomia
Arthropoda
Tardigrada
Onychophora
Protostomia
Hemichoradates
Coelomates
Pseudocoelomates
Rotifera
Nemerteans
Ctenophora
Porifera
Cnidaria
Acoelomates
Nematoda
Platyhelminthes
Radiata
Sedentary worm-like marine animals
Segmentation
Segmentation
Deuterostome
development
Pseudocoelom
True coelom
Radial
symmetry
Protostome development
Three tissue layers (mesoderm)
Bilateral symmetry
Tissues (ectoderm and endoderm)
Multicellularity
Choanoflagellate ancestor
Fig. 29-7, p. 627
Parazoa
Hemichoradates
Echinodermata
Mollusca
Annilda
Deuterostomia
Arthropoda
Onychophora
Tardigrada
Protostomia
Rotifera
Nemerteans
Coelomates
Pseudocoelomates
Nematoda
Platyhelminthes
Ctenophora
Porifera
Cnidaria
Acoelomates
Choradates
Eumetazoa
Bilateria
Radiata
Phylum Chordata: Characteristics
• At some time during life cycle have:
Segmentation
Segmentation
Pseudocoelom
Deuterostome
development
True coelom
Radial
symmetry
–
–
–
–
–
flexible, supporting notochord
dorsal, tubular nerve cord
pharyngeal (gill) slits
muscular postanal tail
endostyle (or thyroid gland)
Protostome development
Three tissue layers (mesoderm)
Bilateral symmetry
Tissues (ectoderm and endoderm)
Multicellularity
Choanoflagellate ancestor
Fig. 29-7, p. 627
Chordate Body Plan
Phylum Chordata
• Subphylum Urochordata (Invertebrate)
• Subphylum Cephalochordata (Invertebrate)
• Subphylum Vertebrata (Vertebrate)
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Chordate Evolution
Subphylum Urochordata
• Tunicates
– Invertebrate
– marine animals with tunics
– suspension-feeders
• Larvae are free swimming
– Most adults are sessile
Incurrent siphon
Ganglion
Oral tentacles
Pharynx with
slits
Excurrent
siphon
Atrium
Endostyle
Tunic
Intestine
Esophagus
Testis
Digestive
gland
Ovary
Heart
Stomach
Fig. 31-5b, p. 672
Tunicate
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Pharynx
with
slits
Incurrent
opening
Larva
Atrium
Excurrent
opening
Nerve cord
Adhesive
papilla
Notochord
Heart
Stomach
0.5 mm
Subphylum Cephalochordata
• Lancelets
– Invertebrate, small, segmented, fishlike animals
Vertebrata
Cephalochordata
(lancelets)
Urochordata
(tunicates)
Chordata
Hemichordata
(acorn worms)
Echinodermata (sea
stars, sea urchins)
Fig. 31-5c, p. 672
Deuterostome
ancestor
Fig. 31-5a, p. 672
Chordate Evolution
Vertebrate Evolution
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Vertebrate Characteristics
• Vertebral column: skeletal axis of body
• Cranium: braincase
• Neural crest cells: determine development of
many structures
• Pronounced cephalization
• Complex brain
• Muscles attached to endoskeleton for
movement
Vertebrate Evolution
KEY CONCEPTS
• Shared derived characters of vertebrates include a
vertebral column, cranium, neural crest cells, and an
endoskeleton of cartilage or bone
Jawless Fishes
• Ostracoderms (extinct)
– among earliest known vertebrates
• Agnathans (hagfishes)
– class Myxini
• Lampreys
. class Cephalaspidomorphi
• no jaws or paired fins; cartilage, gills,
notochord
Jawless Fish: Hagfish
Vertebrate Evolution
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Lampreys
Vertebrate Evolution
Class Chondrichthyes
(Cartilaginous Fishes)
• Includes sharks, rays, skates
• Cartilaginous fishes have
– jaws
– two pairs of fins
– placoid scales
Shark Structure
Early Jawed Fishes
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More developments of Cartilaginous fishes:
- development of sense organs
• Oviparous
• electrorecptors in head
• lateral line organs
Shark Reproduction
– lay eggs
(all fish)
• Ovoviparous
• Internal fertilization
– young enclosed by eggs
– incubated in mother’s body
• Viviparous
– young develop in mother’s uterus
– nutrients transferred from mother’s blood
Vertebrate Evolution
Bony fishes – “Osteicthyes”
24,000 spp.
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Characteristics of Bony fishes
Bony Fishes
•
•
•
•
• Class Actinopterygii
– ray-finned fishes
• Class Actinistia
– coelacanths
skeleton of bone
most oviparous
swim bladder (not all)
bony dermal scales
Modern bony
fishes
• Class Dipnoi
– lungfishes
Lung fishes (3 genera
(lungs – enamel)
Ray-finned
Lobe-finned (lungs)
Lobe-finned fishes (1)
(Coelocanth)
bony ancestor
(lungs)
Modern Bony Fishes
Modern day boney fish
Swim bladder Nerve cord
Dorsal fins
Kidney
Ureter
Caudal fin
Brain
Nostril
Pharynx
Gills
Heart
Gonad
Liver
Stomach Pelvic fin Intestine
Urinary
bladder
Anal fin
Cloaca
Fig. 31-13, p. 680
Lung fish branch: Sarcopterygii
We used to think
• Gave rise to
– lungfishes (class
Dipnoi)
Lungfishes
– coelacanths
(class Actinistia)
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Sarcopterygii
Vertebrate Evolution
• Lungfishes gave rise to tetrapods
– land vertebrates
• Tiktaalik - transitional between fishes and tetrapods
Early Tetrapods
• Early amphibians
– mainly aquatic
– moved onto land to find food, escape predators
– had limbs strong enough to support body weight
on land
Class: Amphibia
- salamanders, frogs, toads, caecilians
• metamorphosis
aquatic larvae
terrestrial adult!!!!
• lungs + skin for gas exchange
• chambered heart:
systemic circulation
pulmonary circulation
• most oviparous - Water!!
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Amniote Evolution
Have body covering that retards water loss
Have physiological mechanisms that
conserve water
Amniotic membrane
Amniotic Egg
(from drying out – temperature)
• Protection
• Keeps from
drying out
• Temperature regulation
Class Reptilia
• A paraphyletic group
– dinosaurs, turtles, lizards, snakes, alligators
• Biologists classify amniotes in two main
groups: diapsids and synapsids
Amniotes
• Diapsids
– turtles, ichthyosaurs, tuataras, squamates
(snakes and lizards), crocodiles, pterosaurs,
saurischian dinosaurs, birds
Diapsids
• Many biologists consider birds as
feathered dinosaurs
– classify birds and most
reptiles as diapsids
• Synapsids
– gave rise to therapsids, which gave rise to
mammals
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Therapsid
Amniote Evolution
4 Groups of Extant Reptiles
Reptile Characteristics
1. Turtles, terrapins, tortoises
2. Snakes
• Reproduction
– internal fertilization
– leathery protective shell around egg
– embryo develops protective membranes
(including amnion)
3. Tuataras
4. Crocadiles, alligators, caimans
Reptile Characteristics
Class: Aves (birds) around 9,000 species
- derived from dinosaurs
• Dry skin with horny scales
• Lungs with many chambers
• Three-chambered heart
– some separation of oxygen-rich and oxygen-poor
blood
- adaptations to flight
• feathers
• streamlined bodies
• light bones (fenestrated)
• No
teeth
- efficient lungs and
circulatory systems
- 4 chambered heart
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Modern Birds
Archaeopteryx
Reptile-like
- reptile teeth
- long tail
- wings w/claws
Bird-like
-wings
- feathers
- furcula
Birds
Birds
• Adaptations for powered flight
– feathers
– wings
– light, hollow bones containing air spaces
• Excrete solid metabolic wastes (uric acid)
• Four-chambered heart
• Well-developed nervous system
• Very efficient lungs
• Excellent vision and hearing
• Endotherms
– maintain constant body temperature
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Mammal Evolution
Mammals
• Characterized by
–
–
–
–
hair
mammary glands
differentiated teeth
three middle-ear bones
• Have highly developed nervous system and
muscular diaphragm
• Are endotherms
Subclass: Holotheria (monotremes)
**** Oviparous!!!!
Subclass: Metatheria (Marsupials)
- Marsupium
-- Viviparous
Marsupials (Subclass Metatheria)
• Include pouched mammals
– kangaroos, opossums
• Young are born in embryonic stage
• Complete development in mother’s
marsupium
– nourished with milk from mammary glands
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Placental Mammals
(Subclass Eutheria)
• Characterized by placenta
– for exchange between embryo and mother
Subclass: Eutheria (Placental mammals)
Viviparous
-
Placenta (organ of exchange
between mother and embryo)
No loss of eggs
Maternal bond
Resources
MYA
On seeing the marsupials in Australia for the
1st time and comparing them to placental
mammals:
200
225
290
“An unbeliever might exclaim „surely two
distinct creators must have been at work”
C. Darwin
350
Mammalia
mammals
(4,600 species)
Aves
birds
(9,000 species)
Reptilia
reptiles
(6,500 species)
Amphibia
amphibians
400
Osteicthyes
Bony fishes
(4,000 species)
400
Chondricthyes
Cartilagenous fishes (850 species)
450-500
Agnatha
Jawless fishes
(24,000 species)
(60 species)
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