Transcript Photosynthesis - Sylmar High School

Chapter 31
The Vertebrates
Lancelet, Branchiostoma
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The Vertebrates
Outline
Chordates
Non-vertebrate Chordates
Vertebrates
- Fishes
- Amphibians
- Reptiles
- Birds
- Mammals
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The Vertebrates
Chordates
Phylum Chordata
Four Main Characteristics
- Notochord
- Nerve Cord
- Pharyngeal Pouches
- Tail
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The Vertebrates
Invertebrate Chordates
Notochord persists and is never replaced by a
vertebral column
Lancets (Subphylum Cephalochordata)
Sea Squirts (Subphylum Urochordata)
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Sea squirt, Halocynthia
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The Vertebrates
Vertebrates
Subphylum Vertebrata
Internal jointed skeleton of vertebrates is living
tissue that grows with the animal
Main axis of 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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Phylogenetic Tree of the Chordates
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The Vertebrates
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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The Vertebrates
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Fishes
Fishes:
Aquatic, gill-breathing vertebrates
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
Lamprey, Petromyzon
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The Vertebrates
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Fishes With Jaws
Gnathostomates have jaws
 Jaws thought to have evolved from first pair of
gill arches of agnathans
 Placoderms
- Extinct jawed fishes of Devonian
- Thought to be ancestral to sharks and bony fish
The Vertebrates
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Cartilaginous Fishes
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, wing-like
fins
Cartilaginous fishes
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The Vertebrates
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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
Swim bladder
- Gas-filled sac in bony fishes
- Volume can be altered to change buoyancy
Ray-finned Fishes
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The Vertebrates
Amphibians
Tetrapods (four limbs)
Hypotheses of tetrapod evolution
Lobe-finned fishes had an evolutionary
advantage due to movement capability
further adaptations promoted by:
- Supply of food on land, and
- Absence of predators
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Lobe-finned Fish vs. Amphibian
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The Vertebrates
Diversity of Amphibians
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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The Vertebrates
Amphibian Features
Usually tetrapods
Lungs usually present in adults
Metamorphosis
Smooth and moist skin
Three-chambered heart
Ectothermic
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Metamorphosis
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Vertebrate Circulatory Pathways
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The Vertebrates
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Reptiles
Class Reptilia
Thought to have evolved from amphibian
ancestors by the Permian period
Practice internal fertilization
Lay eggs protected by a leathery shell (amniotic
egg)
Phylogenetic Tree of Reptiles
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The Vertebrates
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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Reptilian Diversity
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Reptilian Anatomy
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The Vertebrates
Birds
Characteristics of Class Aves
Feathers
Hard-shelled amniotic egg
Four-chambered heart
Often winged
Air sacs
Endothermic
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Bird Anatomy and Flight
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Bird Beaks
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The Vertebrates
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Mammals
Class Mammalia
Thought to have 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
Monotremes and Marsupials
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The Vertebrates
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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
Placental Mammals
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The Vertebrates
Major Orders of Mammals
Perissodactyla
Horses
Artiodactyla
Chiroptera
Bats
Deer
Rodentia
Carnivora
Mice
Cats
Primates
Monkeys
Cetacea
Whales
Proboscidea
Elephants
Lagomorpha
Rabbits
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The Vertebrates
Review
Chordates
Non-vertebrate Chordates
Vertebrates
- Fishes
- Amphibians
- Retiles
- Birds
- Mammals
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Ending Slide Chapter 31
The Vertebrates