Photosynthesis

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(No Transcript)
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Lancelet, Branchiostoma
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Outline

• Chordates
• Non-vertebrate Chordates
• Vertebrates
• Fishes
• Amphibians
• Reptiles
• Birds
• Mammals

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Chordates

• Phylum Chordata
• Four Main Characteristics
• Notochord
• Nerve Cord
• Pharyngeal Pouches
• Tail

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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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Sea squirt, Halocynthia
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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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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
• 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

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Lamprey, Petromyzon
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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

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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

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Cartilaginous fishes
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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

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Ray-finned Fishes
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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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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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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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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)

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Phylogenetic Tree of Reptiles
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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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Reptilian Diversity
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Reptilian Anatomy
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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 Anatomy and Flight
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Bird Beaks
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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

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Monotremes and Marsupials
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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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Placental Mammals
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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

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Review

• Chordates
• Non-vertebrate Chordates
• Vertebrates
• Fishes
• Amphibians
• Retiles
• Birds
• Mammals

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