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Vertebrate Diversity IVertebrate Diversity I
The ProtochordatesThe ProtochordatesSubphylum Vertebrata Subphylum Vertebrata
BIO 112
Q1: Deuterostomes
1) Have radial, indeterminate cleavage
2) Are ancestrally enterocoelous
3) Develop the mouth as the second gut opening
4) All of the above
Deuterostomes and Chordates
• Generic deuterostome characteristics:– Radial, indeterminate cleavage
– Enterocoely
– Deuterostomy
• The four Chordate characteristics:– Notochord
– Pharyngeal gill slits
– Post-anal tail
– Dorsal hollow nerve chord
(+ trends toward segmentation and cephalization)
The “Protochordates”• Ph. Hemichordata
• Ph. Chordata– Subph. Urochordata
– Subph. Cephalochordata
Q2: The only chordate character retainedby adult tunicates is the
1) Notochord
2) Pharyngeal gill slits
3) Dorsal hollow nerve chord
4) Post-anal tail
Q3: The closest protochordatevertebrate ancestors are the
1) Echinoderms
2) Hemichordates
3) Urochordates
4) Cephalochordates
Sub-ph. VertebrataCentral characteristics:
• segmented vertebral column (i.e., backbone) • cranium (brain case: bone or cartilage)• closed circulatory system• neural crest cells
– become teeth, part of cranium, adrenal glands
• nephritic kidneys• semicircular vestibular canals• seconarily schizocoelous
Sub-ph. VertebrataBases for classification
(shared derived traits) :cranium and jaws
lateral appendages
consolidation of vertebrae
cartilagenous vs. bony skeleton
tetrapody and petadactyly
anamniotic vs. amniotic egg
endothermy vs. ectothermy
scales, feathers, fur
milk
extended parental care
Q4: Which of the following is NOTa distinguishing vertebrate character?1) Neural crest cells
2) Nephritic kidneys
3) Radial symmetry
4) A segmented backbone
Class (or Superclass) Agnatha
• Jawless fishes– circular mouths; specialized feeding– notochord persists through life– lack paired appendages– single dorsal nostril
• 2 extant taxa:– Myxini: hagfish– Cephalaspidomorphi: lamprey
Ostracoderms: extinct agnathans
The lamprey -- an ectoparasite
Lamprey on prey
Lamprey mouth -- yikes!
Lamprey ammocoetes larva:(clear affinity with cephalochordates)
A gravel-dwelling filter feeder when young
Hagfish -- a scavenger
This is why it’s called the “slime hag”!
Q6: “Agnathans” derive their namefrom their lack of
1) Paired nostrils
2) Jaws
3) Paired lateral appendages
4) A segmented backbone
Jaws or No Jaws?
• Superclass Agnatha:– Cl. Myxini
– Cl. Cephalaspidomorphi/
Petromyzontia
• Superclass Gnathostomata– Cl. Chondrichthyes
– Cl. Osteichthyes
– C. Amphibia
– Cl. Reptilia
– Cl. Mammalia
– Cl. Aves
The Placoderms: first jawed fishes (now extinct)
Evolution of Jaws from Gill Arches
Cl. Chondrichthyes
• Cartilaginous fishes: sharks, skates, rays– light-weight, elastic skeleton
• Gills
• Paired fins (pectoral and pelvic fins)
• Large oily liver for buoyancy
• Heterocercal tail
• Scavengers or predators
Sharks
Heterocercal tail
Shark jaws with choppers . . .
If jaws evolved from gill arches, where did teeth come from?
Denticles on shark skin
Skates
Manta Ray (or, “BayWatch meets the Chondrichthyes”)
Cl. Osteichthyes
• Bony fishes: about half of all vertebrates!
• Gills with operculum: gill cover
• Swim bladder for buoyancy– derived from outpocketing of pharynx
• flexible pectoral fins– can provide propulsion (not in shark)
Q6: The Osteichthyes differ from the major Chondrichthyes groups in having
1) A swim bladder
2) A bony skeleton
3) Gill covers (opercula)
4) All of the above
Examples of bony fishes
Fish with swim bladder
2 sub-classes of Bony fishes:
• Sub-Cl. Actinopterygii– “ray-finned fish”
– actino = ray
– Very diverse: the majority of fish!
• Sub-Cl. Sarcopterygii– “lobe-finned fish”
– sarco = flesh
– Only 4 genera, but very interesting, evolutionarily
– 2 Orders: Dipnoi, Crossopterygii
The dipnoans
• Lung fish (also have gills . . . )
• “Dipnoan” = double breathing
• Fresh water
• 1 genus each in Africa, Australia, S. America
The Queensland Lung fish
Australian speies
Order Crossopterygii
• The only extant species is the Coelocanth – (Latimeria)
• a living fossil known from 70 m.y. old fossils
• Re-discovered in 1938 in W. Indian Ocean
• the lobed fins evolved into the 4 limbs of the tetrapods” (terrestrial verts)
Can’t get enough of that Latimeria!
The “fishapod” – a likely transition from fish to amphibian
The muscular, bony, lobed fins were nicely pre-adapted for locomotion on land
Tiktaalik roseae – the “fishapod”
~ 380mya
Q7: The most successful and speciosegroup of bony fish are the
1) Chondrichthyes
2) Actinopterygii
3) Dipnoi
4) Crossopterygii
Q8: The bony fish most closelyrelated to our ancestors are the
1) Chondrichthyes
2) Actinopterygii
3) Dipnoi
4) Crossopterygii
Class Amphibia
• Most return to water to reproduce; larvae often have gills
• Amphi-bios = “double life”
• need moist skin for gas exchange– small, inefficient lungs
• fertilization usually external
• are ectotherms
Class Amphibia
• Order Urodela (salamanders)
• Order Anura (toads, frogs)
• Order Apoda (caecilians)
Q9: Why are amphibians called “amphibians”?
1) They all have smooth, thin skins
2) They all must return to the water to reproduce
3) They are all external fertilizers
4) They all have multiple larval forms
O. Urodela -- salamanders
Spotted salamander
• Have Legs and tails (uro = “tail”)
• May have lungs or be lungless
• Terrestrial or aquatic
Red-backed salamander
Red eft -- terrestrial stage
Hellbender -- huge aquatic sally!
O. Anura: frogs, toads
Leopard frog (Rana pipiens)
• Tail-less (a + uro)• Jumpers or hoppers• aquatic larval stage
(the tadpole)
American Toad
Green Frog
O. Apoda -- caecilians
• Legless, burrowing amphibians!
• Mostly tropical
Q10: Salamanders belong to what class of amphibians?
1) Salientia
2) Apoda
3) Urodela
4) Anura
Class Reptilia -- reptiles
• Dry, scaly epidermis -- keratin scales
• lungs
• can reproduce on dry land: – terrestrial (amniotic) egg with shell– internal fertilization
• think about parallels with evolution of plants for a terrestrial existence!
The 3 orders of Reptiles
• O. Chelonia -- turtles
• O. Squamata -- lizards and snakes
• O. Crocodilia -- alligators, crocodiles, caimans
Q11: Which of the following is NOT an adaptation which frees Reptilia from an aquatic developmental stage?
1) Leathery, amniotic eggs
2) Epidermal scales
3) Internal fertilization
4) Live birth
O. Chelonia: turtles
Eastern box turtles
Leatherback sea turtle
An Ogden Nash limerick
The turtle lives 'twixt plated decks
Which practically conceal its sex.
I think it clever of the turtle
In such a fix to be so fertile
Green sea turtle
O. Squamata: lizards and snakes
The Texas horned lizard
Just another pretty face? . . . .
Or the Or the spawnspawn of the Devil!? of the Devil!?
Horned lizard squirting blood from its eyes!
Black rat snake
O. Crocodilia
Crocodile
American Alligator
Nests/Maternal care in Alligators!
Newborn alligator -- terrestrial egg
Q12: In what way are the crocodilians more like birds than like
other reptiles?1) Endothermy (warm-bloodedness)
2) Four-chambered hearts
3) Parental care
4) All of the above
Q13: What is particulary peculiar about turtle anatomy?
1) They have four legs and flexible necks
2) They have scaly skins and clawed feet
3) They lay leathery, amniotic eggs
4) Their pectoral and pelvic girdles are inside their rib cages
Class Aves -- birds
• Feathers: modified scales (keratin)
• Flight skeleton– hollow bones; no heavy teeth– fused skeletal elements
• Flow-through lung
• 4-chambered heart
• Endothermic
• Terrestrial (amniotic) egg
Bird Feathers
Contour feather
Archaeopteryx lithographica
Bird Bones and Feathers
The flight skeleton (chicken)
Non-passeriform Birds
Red-shouldered Hawk
Killdeer
Sandhill Crane
Ruby-throated Hummingbird Mourning Dove
Red-headed Woodpecker
Order Passeriformes
Summer tanagerLoggerhead Shrike
Red-winged Blackbird
Carolina Wren Blue GrosbeakChestnut-sided Warbler
Q14: Feathers were most likely originally an adaptation for
1) flying
2) swimming
3) courtship display
4) retaining body heat
Q15: Birds are the correctly classified as descendants and members of what very
successful vertebrate group?1) Insectivora
2) Chelonia
3) Dinosauria
4) Serpentia
Class Mammalia -- mammals
• Endothermic– hair of keratin (for insulation)– 4-chambered heart– diaphragm
• Mammary glands
• Placenta (not all species)• Teeth: highly modified and specialized
Heterodont dentition (dog)
3 Groups of Mammals:
• Order Monotremata• Egg laying mammals!
• Order Marsupialia• Pouched mammals
• Eutherian Mammals• ~17 orders of placental mammals
Q16: “Heterodont” means
1) Having more than one type of tooth
2) Having different appearing sexes
3) Having four limbs
4) Having five toes on each limb
Monotremes - Protherians
The Platypus – Not good as pets - males have poison spurs on their hindlegs!
Marsupials
• Pouched mammals (the marsupium)
• Order Marsupialia
• Best represented in Australia
• Only one North American representative
Marsupials - Metatherians
Baby koala Tasmanian DevilWombat
Marsupial mole Sugar Glider
Virginia Opossum
This female has nine (!) babies in her marsupium! (no wonder she looks testy!)
Newborn Opossum
Evolutionary Convergence of Placentals and
Marsupials
Q17: What distinguishes the protherians (montremes) from the
therian mammals?1) Protherians have no hair
2) Protherians are oviparous (lay eggs)
3) Protherians are external fertilizers
4) Protherians bite
Q18: What is the “marsupium” for which the marsupials (metatherians) are
named?1) A pouch
2) A unique set of teeth
3) A heavy tail for balancing
4) A hopping gait
Q19: Even though marsupials originated in South America, there is now only one
North American species. What is it?
1) The armadillo
2) The deer
3) The opossum
4) The aardvark
Placental Mammals - Eutherians
• ~17 Orders of mammals
• A very diverse, successful group
• The young complete their development within the mother’s womb -- the placenta helps provide them with nourishment and does gas exchange
The four biogeographical clades of placental mammals
• Xenarthra – sloths, true anteaters, armadillos• Afrotheria – elephants, manatees, sengis,
aardvarks• Laurasiatheria – ungulates, whales and dolphins,
insectivores, bats, carnivores, scaly anteaters• Euarchontoglires – rodents, rabbits and picas, tree
shrews, colugos, primates
Representative Placental Mammals
Clockwise from top left: Probiscidea, Sirenia, Cingulata, Primates, Lagomorpha, Rodentia
More Mammalian Orders:
Clockwise from top left: Carnivora, Cetartiodactyla, Cetartiodactyla, Perissodactyla, Chiroptera, Soricomorpha
Order Primates
Top: Gibbon Bottom: Spider monkey Gorilla
Primate Phylogenetic
Tree
Q20: What distinguishes the placental mammals from marsupials and
monotremes?1) Production of milk
2) Live birth
3) Care of the young
4) Nourishment of embryos by a placenta
Q21: To which order of mammals do you belong?
1) Cetacea
2) Proboscidea
3) Rodentia
4) Primates
Q22: Which of the following is not an order of ungulates (toe-nail walkers)?1) Artiodactyla
2) Perissodactyla
3) Carnivora
4) All of the above are ungulates
