Vertebrate Diversity I
The Protochordates
Subphylum Vertebrata
BIO 112
Q1: Deuterostomes
1)
2)
3)
4)
Have radial, indeterminate cleavage
Are ancestrally enterocoelous
Develop the mouth as the second gut opening
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 retained
by adult tunicates is the
1)
2)
3)
4)
Notochord
Pharyngeal gill slits
Dorsal hollow nerve chord
Post-anal tail
Q3: The closest protochordate
vertebrate ancestors are the
1)
2)
3)
4)
Echinoderms
Hemichordates
Urochordates
Cephalochordates
Sub-ph. Vertebrata
Central 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. Vertebrata
Bases 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 NOT
a distinguishing vertebrate character?
1)
2)
3)
4)
Neural crest cells
Nephritic kidneys
Radial symmetry
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 name
from their lack of
1)
2)
3)
4)
Paired nostrils
Jaws
Paired lateral appendages
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)
2)
3)
4)
A swim bladder
A bony skeleton
Gill covers (opercula)
All of the above
Examples of bony fishes
Fish with swim bladder
2 sub-classes of Bony fishes:
• Sub-Cl. Actinopterygii
• Sub-Cl. Sarcopterygii
– “ray-finned fish”
– actino = ray
– “lobe-finned fish”
– sarco = flesh
– Very diverse: the
majority of fish!
– 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
Tiktaalik roseae
– the “fishapod”
~ 380mya
The muscular, bony, lobed fins were nicely preadapted for locomotion on land
Q7: The most successful and speciose
group of bony fish are the
1)
2)
3)
4)
Chondrichthyes
Actinopterygii
Dipnoi
Crossopterygii
Q8: The bony fish most closely
related to our ancestors are the
1)
2)
3)
4)
Chondrichthyes
Actinopterygii
Dipnoi
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)
2)
3)
4)
They all have smooth, thin skins
They all must return to the water to reproduce
They are all external fertilizers
They all have multiple larval forms
O. Urodela -- salamanders
• Have Legs and tails (uro = “tail”)
• May have lungs or be lungless
• Terrestrial or aquatic
Spotted salamander
Red-backed salamander
Red eft -- terrestrial stage
Hellbender -- huge aquatic sally!
O. Anura: frogs, toads
• Tail-less (a + uro)
• Jumpers or hoppers
• aquatic larval stage
(the tadpole)
Leopard frog (Rana pipiens)
American Toad
Green Frog
O. Apoda -- caecilians
• Legless, burrowing amphibians!
• Mostly tropical
Q10: Salamanders belong to what
class of amphibians?
1)
2)
3)
4)
Salientia
Apoda
Urodela
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)
2)
3)
4)
Leathery, amniotic eggs
Epidermal scales
Internal fertilization
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 spawn 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)
2)
3)
4)
Endothermy (warm-bloodedness)
Four-chambered hearts
Parental care
All of the above
Q13:
1)
2)
3)
4)
What is particulary peculiar
about turtle anatomy?
They have four legs and flexible necks
They have scaly skins and clawed feet
They lay leathery, amniotic eggs
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
Killdeer
Red-shouldered Hawk
Red-headed
Woodpecker
Sandhill Crane
Ruby-throated Hummingbird
Mourning Dove
Order Passeriformes
Summer tanager
Red-winged Blackbird
Loggerhead Shrike
Carolina Wren
Chestnut-sided Warbler
Blue Grosbeak
Q14: Feathers were most likely
originally an adaptation for
1)
2)
3)
4)
flying
swimming
courtship display
retaining body heat
Q15: Birds are the correctly classified as
descendants and members of what very
successful vertebrate group?
1)
2)
3)
4)
Insectivora
Chelonia
Dinosauria
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:
1)
2)
3)
4)
“Heterodont” means
Having more than one type of tooth
Having different appearing sexes
Having four limbs
Having five toes on each limb
Monotremes - Protherians
The Platypus – Not good as pets - males
have poison spurs on their hindlegs!
The other monotreme
Echidnas - “spiny
anteaters”
Marsupials
• Pouched mammals
(the marsupium)
• Order Marsupialia
• Best represented in
Australia
• Only one North
American
representative
Marsupials - Metatherians
Baby koala
Tasmanian Devil
Marsupial mole
Wombat
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)
2)
3)
4)
Protherians have no hair
Protherians are oviparous (lay eggs)
Protherians are external fertilizers
Protherians bite
Q18: What is the “marsupium” for
which the marsupials (metatherians) are
named?
1)
2)
3)
4)
A pouch
A unique set of teeth
A heavy tail for balancing
A hopping gait
Q19: Even though marsupials originated
in South America, there is now only one
North American species. What is it?
1)
2)
3)
4)
The armadillo
The deer
The opossum
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)
2)
3)
4)
Production of milk
Live birth
Care of the young
Nourishment of embryos by a placenta
Q21: To which order of mammals do
you belong?
1)
2)
3)
4)
Cetacea
Proboscidea
Rodentia
Primates
Q22: Which of the following is not an
order of ungulates (toe-nail walkers)?
1)
2)
3)
4)
Artiodactyla
Perissodactyla
Carnivora
All of the above are ungulates