Transcript The Deuterostomes Chapter 31 Mader: Biology 8th Ed. Outline • • Echinoderms Chordates – Invertebrates – Vertebrates  Fishes  Amphibians  Retiles  Birds  Mammals Mader: Biology 8th Ed.

The Deuterostomes
Chapter 31
Mader: Biology 8th Ed.
Outline
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Echinoderms
Chordates
– Invertebrates
– Vertebrates
 Fishes
 Amphibians
 Retiles
 Birds
 Mammals
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Echinoderms
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Phylum Echinodermata
– Echinoderms have an exoskeleton of
spine-bearing, calcium-rich plates.
 Class Crinoidea - Sea lilies.
 Class Holothuroidea - Sea cucumbers.
 Class Ophiuroidea - Brittle stars.
 Class Asteroidea - Sea stars.
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Sea Stars
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Each arm has a groove lined by tube feet.
– Feeding structure.
 Stomach secretes enzymes.
In each arm, coelom contains a pair of
digestive glands and gonads.
Locomotion depends on water vascular
system.
Simple circulatory system.
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Echinoderms
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Chordates
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Phylum Chordata
– Four Main Characteristics
 Notochord
 Nerve Cord
 Pharyngeal Pouches
 Tail
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Invertebrate Chordates
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Notochord persists and is never replaced by
a vertebral column.
– Lancets (Subphylum Cephalochordata)
– Sea Squirts (Subphylum Urochordata)
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Invertebrate Chordates
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Vertebrates
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Subphylum Vertebrata
– Vertebrate skeleton is living tissue that
grows with the animal.
 Main axis of internal jointed skeleton
consists of vertebral columns and a
skull that encloses the brain.
 Cephalization is accompanied by
sense organs.
 Evolution of jaws and predation.
 Amnion allows reproduction on land.
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Vertebrate Features
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Living endoskeleton with vertebral column.
Closed circulatory system.
Paired appendages.
Efficient respiration and excretion.
High degree of cephalization.
Adapted to active lifestyles.
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Fishes
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Fishes are aquatic, gill-breathing vertebrates
that usually have fins and scale-covered
skin.
– Jawless fishes (Superclass Agnatha)
 Ostracoderms - earliest vertebrate
fossils.
 Lampreys and hagfishes are modernday jawless fishes that lack a bony
skeleton.
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Jawless Fishes
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Fishes With Jaws
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Gnathostomates have jaws.
– Believed to have evolved from first pair of
gill arches of agnathans.
 Placoderms, extinct jawed fishes of
Devonian period, are believed to be
ancestral to early sharks and bony fish.
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Cartilaginous Fishes
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Class Chondrichthyes have a skeleton of
cartilage instead of bone.
– Cartilaginous Fishes
 Sharks, rays, skates
 Lack gill cover of bony fish.
 Utilize lateral line system.
 Filter feeders and predators.
 Pectoral fins can be enlarged into large,
winglike fins.
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Cartilaginous Fishes
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Bony Fishes
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Class Osteichthyes have a skeleton of bone.
– Most are ray-finned fishes.
 Lobe-finned fishes are small subgroup
with fleshy fins supported by central
bones.
– Bony fish have a gas-filled sac (swim
bladder) whose pressure can be altered to
change buoyancy.
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Ray-Finned Fishes
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Amphibians
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Tetrapods (Have four limbs)
– Hypotheses of evolution.
 Lobe-finned fishes had an evolutionary
advantage due to movement capability.
 Supply of food on land and the absence
of predators promoted further
adaptations.
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Lobe-Finned Fish Versus Amphibians
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Diversity of Amphibians
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Amphibians today occur in three groups:
– Salamanders and newts
 Salamanders practice internal
fertilization.
– Frogs and toads
 Tailless
– Caecilians
 Legless, sightless, worm-shaped
Most return to water for reproduction.
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Amphibians
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Amphibian Features
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Usually tetrapods.
Lungs usually present in adults.
Metamorphosis
Smooth and moist skin.
Three-chambered heart.
Ectothermic
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Vertebrate Circulatory Systems
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Reptiles
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Class Reptilia is believed to have evolved
from amphibian ancestors by the Permian
period.
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Phylogenetic Tree
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Reptiles
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Practice internal fertilization and lay eggs
protected by a leathery shell (amniotic
egg).
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Anatomy and Physiology of Reptiles
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Reptiles have a thick, scaly skin that is
keratinized and impermeable to water.
– Usually tetrapods.
– Lungs with expandable rib cage.
– Shelled amniotic egg.
– Dry, scaly skin.
– Ectothermic
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Mader: Biology 8th Ed.
Birds
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Characteristics of Class Aves
– Feathers
– Hard-shelled amniotic egg.
– Four-chambered heart.
– Often winged
– Air sacs
– Endothermic
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Mader: Biology 8th Ed.
Bird Beaks
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Mammals
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Class Mammalia evolved during the
Mesozoic era from therapsids.
– Mammalian skull accommodates a larger
brain relative to body size.
– Chief characteristics and hair and milkproducing mammary glands.
– Infant Dependency
– Internal Development
– Differentiated Teeth
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Mammals
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Monotremes - Hard-shelled amniotic eggs.
Marsupials - Females contain pouch.
Placentals - Females have organ for
exchange of maternal and placental blood.
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Major Orders of Mammals
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Perissodactyla
– Horses
Artiodactyla
– Deer
Carnivora
– Cats
Primates
– Monkeys
Cetacea
– Whales
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Chiroptera
– Bats
Rodentia
– Mice
Proboscidea
– Elephants
Lagomorpha
– Rabbits
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Review
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Echinoderms
Chordates
– Invertebrates
– Vertebrates
 Fishes
 Amphibians
 Retiles
 Birds
 Mammals
Mader: Biology 8th Ed.
Mader: Biology 8th Ed.