four key chordate characteristics. invertebrate chordates cephalochordata -lancelets/amphioxus...
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Four Key Chordate Characteristics
Invertebrate Chordates• Cephalochordata
-Lancelets/Amphioxus• Urochordata
–Tunicates/Sea Squirts• Vertebrates may have
evolved from a sexually mature larval urochordate
• Metamorphosis is eliminated
Subphylum Cephalochordata: the Lancelet Branchiostoma
Lancelet Anatomy
Subphylum UrochordataTunicate Anatomy
Subphylum: Vertebrata
• Cephalization (Craniates are chordates with a head)
• Vertebrate skeleton
• Brain protected by skull
• Closed circulatory system
• Gills or lungs
• Kidneys for excretion
Fishes• Very successful vertebrates–Fast streamlined body plan–Excellent sensory organs,
lateral line system–Highly developed organs for
osmoregulation–Complex behavior–2 chambered heart–Swim bladder
Fish
A Sea Lamprey (Class Cephalospidomorphi)
A Hagfish (Class Myxini)
Hypothesis for the evolution of vertebrate jaws from two pairs of skeletal rods
Gnathostomes Are Vertebrates That Have Jaws
Class Chondrichthyes
Ray-finned Fishes; Yellow Perch; Have thin bony spines connected by a layer of skin to form the fins
Ray-finned Fishes (Class Actinopterygii): long-snouted sea horse
A coelocanth (Class Actinistia), a Lobe-finned Fish, has rod-shaped bones and few bones in its fin bases
Coelacanth at the Field Museum - Chicago
Life on LandProblems:
• No support on land
• Gills stick together
• Ammonia no longer a good source of excretory waste
• Dehydration
• Sound/light /smell is perceived differently on land
Solutions• cartilage bone• Lungs• Excrete
concentrated urea uric acid
• Skin and scales• Adapt ability to
perceive sound, smell and light differently
Skeleton of Acanthostega, a Devonian tetrapod fish
Class Amphibia• Shoulder hip and girdles act to
strengthen limbs for life on land• Heart with 3 chambers• They are not completely free from
water–Reproduction–Dessication (skin must stay wet)
Amphibian Orders: Newt (left) Order Urodela, frog (right) Order Anura
Frogs
“Dual life” of a frog (Rana temporaria)
Class Reptilia
• Completely free from water• Amniotic egg• Scaly skin• 3-4 chambered heart• Uric acid as nitrogenous waste• Ectothermic
Extant Reptiles: Desert tortoise (top left), lizard (top right), king snake (bottom left),
alligators (bottom right)
Banded Gecko, Coleonyx varigatus
Emerald Tree Boa
Sea Turtle
Archaeopteryx
Archaeopteryx
Cretaceous theropod dinosaurs with putative feathers from Chinese
sediments: Caudipteryx
Class Aves• Evolved from reptiles• Flying dinosaurs• Bones and feathers are
adapted for flight• 4 chambered heart• Endothermic• Efficient 1 way lungs• Excrete uric acid
A small sample of birds: Blue-footed boobies (top left), male peacock (top right), penguins (bottom left), perching bird (bottom right)
Class Mammalia• Hair• Mammary glands• Placenta connects fetus to mom
(missing in marsupials)• Diaphragm for ventilation of
lungs• 4 chambered heart• Endothermic• Large brains• Diverged from reptilian
ancestors earlier than the birds
Major Groups of Mammals• Monotremes:
–Platypuses, spiny anteater - lay eggs
–Mixture of reptilian and mammalian traits
• Marsupials–Non-placental – Kangaroo, opossum –Young born early and complete
development within pouch• Placental Mammals – bats, dogs, us!
Major Orders of Mammals (Monotremata-Sirenia)
Major Orders of Mammals (Edentata-Primates)
Major Orders of Mammals (Carnivora-Cetaceans)
Major Orders of Mammals (Perissodactyla-Insectivora)
Hypothetical Cladogram of Mammals
A Phylogenetic Tree of Primates
Primate Diversity
Prosimians: Lemurs
A Capuchin, a New World Monkey (left), and a Vervet, an Old World Monkey (rt)
Arboreal, no sitting pads or estrus swelling, prehensile tail
Sitting pads, estrus swelling, generally larger
Others: squirrel monkey, spider monkey, howler monkey
Others: baboon, macaque,Colobus, Rhesus
Apes: Gibbon (top left), orangutan (top right), gorilla (bottom left), chimpanzee (bottom right)
Bonobo with Infant
Jane Goodall, well known for her studiesof chimpanzees
Major Orders of Mammals (Edentata-Primates)
Major Orders of Mammals (Edentata-Primates)
Major Orders of Mammals (Carnivora-Cetaceans)
Major Orders of Mammals (Perissodactyla-Insectivora)
HumanPlace the following organisms on the
phylogenetic tree in terms of theirrelationship to the human:spider monkey, bush baby,orangutan, baboon, siamang.
Chimp
1) Name two Anthropoids.
2) What behavior in chimpanzees was Jane Goodall the first to document?
3) Name one animal from which Ken Miller showed several transitional fossils.
4) What two things are necessary for speciation to occur?
5) The Kaibab and Abert squirrel live on either side of the Grand Canyon and over 10,000 years ago were one species. This demonstrates…
6) If many species evolve from one common ancestor such as occurred with Darwin’s finches this demonstrates the concept of:
7) Other than the chimpanzee, name one other Great Ape.
8) All of the great apes have ______ chromosomes in each of their cells.