mader: biology 8 th ed. the deuterostomes chapter 31
TRANSCRIPT
Mader: Biology 8th Ed.
The Deuterostomes
Chapter 31
Mader: Biology 8th Ed.
Outline
• Echinoderms• Chordates
– Invertebrates– Vertebrates
FishesAmphibiansRetilesBirdsMammals
Mader: Biology 8th Ed.
Echinoderms
• 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
• 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
• Phylum Chordata– Four Main Characteristics
NotochordNerve CordPharyngeal PouchesTail
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Invertebrate Chordates
• 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
• 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
• 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
• 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 modern-day jawless fishes that lack a bony skeleton.
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Jawless Fishes
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Fishes With Jaws
• 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
• Class Chondrichthyes have a skeleton of cartilage instead of bone.– Cartilaginous Fishes
Sharks, rays, skatesLack 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
Mader: Biology 8th Ed.
Bony Fishes
• 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
• 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
• Amphibians today occur in three groups:– Salamanders and newts
Salamanders practice internal fertilization.
– Frogs and toadsTailless
– CaeciliansLegless, sightless, worm-shaped
• Most return to water for reproduction.
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Amphibians
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Amphibian Features
• 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
• 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– Practice internal fertilization and lay eggs
protected by a leathery shell (amniotic egg).
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Anatomy and Physiology of Reptiles
• 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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Birds
• Characteristics of Class Aves– Feathers– Hard-shelled amniotic egg.– Four-chambered heart.– Often winged– Air sacs– Endothermic
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Bird Beaks
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Mammals
• Class Mammalia evolved during the Mesozoic era from therapsids.– Mammalian skull accommodates a larger
brain relative to body size.– Chief characteristics and hair and milk-
producing mammary glands.– Infant Dependency– Internal Development– Differentiated Teeth
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Mammals
• 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
• Perissodactyla– Horses
• Artiodactyla– Deer
• Carnivora– Cats
• Primates– Monkeys
• Cetacea– Whales
• Chiroptera– Bats
• Rodentia– Mice
• Proboscidea– Elephants
• Lagomorpha– Rabbits
Mader: Biology 8th Ed.
Review• Echinoderms• Chordates
– Invertebrates– Vertebrates
FishesAmphibiansRetilesBirdsMammals
Mader: Biology 8th Ed.