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 Urochordata Tunicate 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

Fossilized and modern coelocanths

Life on Land Problems: 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

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 studies of chimpanzees

Major Orders of Mammals (Edentata-Primates)

Major Orders of Mammals (Carnivora-Cetaceans)

Major Orders of Mammals (Perissodactyla-Insectivora)

Human Place the following organisms on the phylogenetic tree in terms of their relationship 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.