Vertebrate Diversity I The Protochordates Subphylum Vertebrata BIO 112

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!

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 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