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BIOL 2210 > Final Exam (Lectures 25 - 35) > Flashcards

Final Exam (Lectures 25 - 35) Flashcards

1
Q

When did the dinosaurs go extinct? **memorize this date

A

65 mya (end of the Mesozoic)

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2
Q

What are the two groups of Mesozoic diapsids?

A

1) lepidosauromorpha (lepidosaurs+extinct relatives)

2) archosauromorpha (archosaurs+extinct relatives) “ruling reptiles”

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3
Q

Name some marine Lepidosauromorphs.

A
  • are secondarily aquatic
  • NOT dinosaurs
  • placodonts, plesiosaurs, ichthyosaurs, mosasaurs
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4
Q

Placodonts: Characteristics

A
  • “plate tooth”
  • extensive bone development to reduce buoyancy for diving, including dermal armour
  • some turtle-like and some dugong-like (herbivores)
  • convergent evolution
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5
Q

Plesiosaurs: Characteristics

A
  • long-necked and short-necked
  • pelagic predators
  • trunk rigid, likely rowed through water with limbs
  • hyperphalangy / hyperdactyly
  • viviparous
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6
Q

Pelagic

A

live at the surface of the ocean

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7
Q

Hyperphalangy / hyperdactyly

A

an increased number of phalanges

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8
Q

Ichthyosaurs: Characteristics

A
  • pelagic predators
  • shark, dolphin or cetacean-like
  • hypocercal tail, forelimbs and hindlimbs
  • hyperphalangy / hyperdactyly
  • viviparous
  • born tail first like extant cetaceans
  • convergent evolution
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9
Q

Mosasaurs: Characteristics

A
  • varanid lizards or sister to varanids (monitor lizard)
  • pelagic predators
  • swam using trunk musculature
  • up to 17 m
  • highly kinetic skulls
  • viviparous
  • born tailfirst like extant marine mammals
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10
Q

Archosaur: synapomorphies

A
  • antorbital fenestra on each side
  • orbit shaped like inverted triangle
  • mandibular fenestrae
  • laterally compressed teeth, set in sockets
  • fourth trocanter on femur (site of insertion of caudofemoral muscle)
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11
Q

Which are the holes in the skull of Archosaurs? What are their functions?

A
  • orbit, mandibular fenestrae, antorbital fenestra

- provides additional sites of muscle attachment and lightens the skull

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12
Q

What are two subgroups of Archosauromorpha? Give some examples.

A

1) Crurotarsi: Phytosaurs (extinct) and Crocodilians (extant)
2) Ornithodira: Pterosaurs (extinct), “dinosaurs” (extinct) and birds (extant)

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13
Q

Archosauromorpha: Crurotarsi: Characteristics

A
  • “cross ankles”
  • diagonal hinge
  • sprawling posture
  • skull often massive
  • neck short and strong
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14
Q

Archosauromorpha: Crurotarsi (high degree of convergence): Phytosaurs: Characterisics

A
  • “plant reptile”
  • large (up to 12m long)
  • long snouts, heavily armoured
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15
Q

How are phytosaurs different from crocodiles?

A
  • nostrils near or above level of eyes (rather than end of snout)
  • lacked bony secondary palate separating nasal passages from mouth
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16
Q

Archosauromorpha: Crurotarsi (high degree of convergence): Crocodilians: Characteristics

A
  • familiar-looking crocodiles appeared in Late Jurassic, after extinction of phytosaurs
  • radiation during Cretaceous
  • extension of warm climates into higher latitudes
  • semi-aquatic, predatory
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17
Q

Order the important time periods from oldest to most present.

A

Triassic (oldest)
Jurassic
Cretaceous (most present) *end of Cretaceous 65mya when dinosaurs went extinct

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18
Q

Archosauromorpha: Crurotarsi (high degree of convergence): Extinct Crocodilians: Sarcosuchus imperator

A
  • “flesh crocodile emperor”
  • up to 12m, 8 tons
  • in Africa, approx. 100 mya
  • eye sockets rotated upwards
  • likely fed on land animals
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19
Q

Archosauromorpha: Ornithodira: Characteristics

A
  • “bird neck”
  • long anterior cervical vertebrae
  • interclavicles absent, clavicles reduced or absent
  • upright posture
  • horizontal hinge
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20
Q

Archosauromorpha: Ornithodira: Pterosaurs: Pterodactyls

A

-where we see the evolution of powered flight fifty million years ago (before birds)

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21
Q

Why are “dinosaurs” in brackets?

A

because it is paraphyletic if birds are excluded from dinosaur lineage

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22
Q

Archosauromorpha: Ornithodira: Pterosaurs: Characteristics

A
  • “wing lizards”
  • Pterodactylus (small) and Quetzalcoatlus (large)
  • 50 my before birds
  • wing morphology completely different from birds (independent evolution of wings-Pteranodon)
  • elongate 4th finger supported by membrane attached to side of body
  • powered flight due to crests on bones for attachment of flight muscles
  • walking ability on hind limbs
  • NOT dinosaurs
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23
Q

Archosauromorpha: Ornithodira: Pterosaurs: Why do they have high degree of convergence with birds?

A
  • hollow long bones
  • well-developed sternum (although without keel)
  • good vision, balance, coordination
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24
Q

Archosauromorpha: Ornithodira: Pterosaurs: Feeding specializations

A
  • sharp conical teeth
  • fine teeth for straining
  • forceps-like jaws
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25
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Two lineages?

A

1) Ornithischia
2) Saurischia (includes birds)
* paraphyletic group if birds are excluded

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26
Q

Are pterodactyls dinosaurs?

A

NO

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27
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: What characteristics indicate dinosaurs had a bipedal common ancestor?

A
  • moving legs under body shortened pubofemoral and ischiofemoral muscles
  • shorter muscles less effective
  • both lineages therefore “reorganized” pubis and ischium but in different ways
  • both lineages with secondarily quadrupedal forms
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28
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Ornithischian: Characteristics

A
  • birds don’t belong in this group
  • “bird hips” = pubis downward, toward the tail, parallel with ischium, resembles modern bird hip (but secondarily derived in birds)
  • all herbivores
  • predentary (unique) and premaxilla form beak for grasping vegetation
  • low-crowned cheek teeth
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29
Q

Bird hips vs lizard hips

A

bird hips=pubis downwards, toward tail, parallel with ischium
lizard hip=pubis forward

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30
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Ornithischian: How do they differ to saurischians?

A
  • Ornithischians radiated into more diverse morphological forms than did herbivorous saurischians
  • not as bipedal as large saurischians
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31
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Ornithischian: What are the three groups?

A

1) Thyreophora: “shield bearers”, quadrupedal, armoured dinosaurs (stegasaurs, ankylosaurs)
2) Ornithopoda: “bird feet”, bipedal, hadrosaurs (duck-billed dinosaurs, parasaurolophus), iguanodon, hypsilophodon
3) Marginocephalia: “ridge head”, bipedal pachycephalosaurs, quadrupedal ceratopsian (triceratops, protoceratops, pentaceratops)

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32
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Ornithischian: Thyreophora: Stegasaur

A
  • front legs shorter than hind legs
  • grazed on low-growing plants
  • horny beak at front of jaws
  • teeth unspecialized
  • two pairs of spikes on tail
  • two rows of plates along vertebral column as armour for protection and heat exchange (highly vascularized)
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33
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Ornithischian: Thyreophora: Ankylosaur

A
  • fused osteoderms in skin of neck, back, hips, tail
  • bony plates on skull, jaws, eyelids
  • short tails with mace-like club
  • fused, distended vertebrae
  • horny spines on back and sides
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34
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Ornithischian: Ornithopoda: Iguanodon

A
  • first recognized dinosaur fossil
  • “bird feet” = three-toed feet (but many early forms with four)
  • no armour
  • more mobile
  • horny beak
  • bipedal, but some quadrupedal while eating
  • one of the most successful herbivore groups in Cretaceous due to sophisticated chewing apparatus (hypsilophodon)
  • specialized teeth (unusual in anything but mammals)
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35
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Ornithischian: Ornithopoda: Hadrosaurs (Duck-billed dinosaurs)

A
  • derived ornithopods
  • many diverse rear teeth that are rapidly replaced
  • stiff tail strengthened by ossified tendons for balance (no drag on the ground)
  • evidence of extended parental care (ex-Maiasaura=”good mother reptile”)
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36
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Ornithischian: Ornithopoda: Hadrosaurs (Duck-billed dinosaurs):
Parasaurolophus

A
  • with or without crests formed by nasal and maxillary or premaxillary bones
  • nasal passages ran through crests that may have been used for species-specific vocalization and visual displays (especially in hollow-crested forms)
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37
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Ornithischian: Ornithopoda: Hadrosaurs (Duck-billed dinosaurs):
Maiasaura

A
  • “good mother reptile”
  • migrated to well-defined nesting grounds
  • warming of eggs likely provided by vegetation (seen in extant crocodilians and some birds)
  • extended parental care
  • parent may have responded to high-frequency vocalizations of juveniles
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38
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Ornithischian: Marginocephalia: Pentaceratops

A
  • “ridge head or fringe head”
  • shell of bone extending back over occipital region of skull
  • highly specialized herbivores
  • last group of ornithischians to appear in fossil record
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39
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Ornithischian: Marginocephalia: Pachycephalosaur

A
  • “thick headed”
  • bipedal
  • thick bony dome on skull roof not used as battering ram but for flank-butting or wrsetling
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40
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Ornithischian: Marginocephalia: Ceratopsians

A
  • early forms bipedal with no head frill
  • later forms obligate quadrupeds (ex-Protoceratops)
  • frill past shoulders in more derived forms
  • origin for powerful jaw muscles
  • knifelike teeth for shearing vegetation
  • sexual dimorphism in frills also suggest role in mating
  • frills may also have functioned in thermal regulation (large surface area)
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41
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Ornithischian: Marginocephalia: Ceratopsians:
Protoceratops

A
  • modest frill over neck formed by enlargement of parietal and squamosal bones
  • without nasal horn
  • obligate quadruped
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42
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Ornithischian: Marginocephalia: Ceratopsians: Triceratops

A

-nasal and brow horns in derived forms likely for defense and intraspecifc combat

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43
Q

Quadruped vs tetrapod vs bipedal

A

Quadruped: four feet
Tetrapod: a phylogenetic grouping that have four feet
Bipedal: uses only two legs for walking

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44
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Saurischian: Characteristics

A
  • “lizard hips” = pubis forward

- true bird hip seen in modern birds evolved later within this lineage, in the maniraptors

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45
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Saurischian: What are the two lineages?

A

1) Sauropodomorpha: mostly quadrupedal herbivores

2) Theropods: bipedal carnivores, includes birds

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46
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Saurischian: Sauropodomorpha

A
  • “long necks” due to shifts from low-growing flora to taller conifers during late Triassic
  • Prosaurapods and Sauropods
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47
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Saurischian: Sauropodomorpha:
Sauropods: Characteristics

A
  • Brachiosaurus=”arm lizard”
  • Diplodocus with teeth only at front of mouth
  • Apatosaurus=Brontosaurus? with longer arms, longer forelegs than hindlegs
  • largest terrestrial vertebrates known
  • one of the most long-lived groups of dinosaurs
  • found on all continents except Antarctica
  • long necks and tails for defense or combat
  • tail stiffened by hemal arches
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48
Q

Gastrolith

A
  • a stomach stone or gizzard stone, is a rock held inside a gastrointestinal tract
  • are retained in the muscular gizzard and used to grind food in animals lacking suitable grinding teeth
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49
Q

Since Sauropods like the Diplodocus has teeth at only the front of the mouth (unlike Hadrosaurs), very little of the food processing occurs in the mouth (compared to Hadrosaurs). What adaptation do Sauropods have to help break down the food?

A

not gastroliths but likely a symbiotic microorganism that helps with the long passage time of food during digestion

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50
Q

What adaptations are seen in Sauropods for their extreme size?

A
  • vertebrae with pleurocoels (hollow) for air sacs
  • massive vertebrae with well-developed neural arches
  • ligaments transmitted force from one arch to adjacent ones
  • head and tail supported by heavy ligament
  • track marks show tail carried, not dragged
  • massive elephant-like feet
  • limbs held directly under the body
  • knees locked when walking
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51
Q

Pleurocoels

A

set of hollow depressions on the lateral portions of the vertebrae in dinosaurs, which served to decrease the weight of these bones without sacrificing strength

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52
Q

What did early paleontologists believe about Sauropods due to their huge weight and size?

A
  • thought weight could not be supported on land
  • must be semi-aquatic
  • contradicted by recent mechanical analyses of the skeleton
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53
Q

What can be said about the metabolism of Sauropods?

A
  • high and stable body temperature without elevated metabolic rates
  • “gigantothermy”
  • energy requirement for endotherm probably would have been prohibitively high
  • not endothermic or Exothermic but gigantothermic
  • are probably both warm blooded and cold blooded
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54
Q

What can be said about Sauropods’ behaviours?

A
  • trackways suggest herdlike behaviour with young in the middle
  • laid eggs in nests dug in soil
  • nests are too close together to allow incubation (so no incubation)
  • no direct evidence of parental care (unlike Hadrosaurs)
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55
Q

What was found in Argentina in 1998 about Sauropods?

A
  • thousands of sauropod eggs found
  • found in clusters up to five feet long
  • cover one square mile
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56
Q

Compare Sauropods and Hadrosaurs.

A

Sauropods:

  • single row of teeth
  • food processing does not occur in the mouth but by a symbiosis with a microorganism
  • no direct evidence of parental care

Hadrosaurs:

  • multiple rows of teeth
  • lots of food processing occurs in the mouth
  • evidence of parental care
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57
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Saurischian: Theropoda

A
  • bipedal carnivores
  • includes birds
  • have furcula (wishbone, formed by fusion of clavicles, preceded appearance of flight, a synapomorphy shared with birds)
  • some with protofeathers = single hollow filaments, composed of beta keratin unique to feathers
  • reports in 1996 of non-avian dinosaurs with feathers in more derived theropods
  • early offshoots are ceratosaurs and carnosaurs
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58
Q

Furcula

A
  • wishbone
  • formed by fusion of clavicles
  • preceded appearance of flight
  • synapomorphy of Theropoda and birds
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59
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Saurischian: Theropoda: Coelurosaur

A
  • “coel”=hollow, “uro”=tail, “saur”=lizard
  • monophyletic subgroup of theropods
  • excludes ceratosaurs and carnosaurs
  • includes tyrannosaurs and maniraptors (dromeosaurs and birds)
  • synapomorphy=light bones, hollow tail vertebrae
  • many with feathers
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60
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Saurischian: Theropoda: Coelurosaur: Tyrannosaurs

A
  • early tyrannosaurs were small with long arms and legs
  • there was an increase in skull, jaw, teeth size and strength then overall size
  • ex) T-rex
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61
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Saurischian: Theropoda: Coelurosaur: Tyrannosaurs: T-rex

A
  • from Late Cretaceous
  • short front legs
  • only 2 small fingers on each hand
  • not a fast runner
  • used skull as a weapon
  • a lizard hip due to pubis forward
  • large head but lightened by antorbital and mandibular fenestrae
  • powerful jaw muscles (alligator and tasmanian devil only extant species capable of exerting comparable force)
  • serrated teeth up to 15cm long (bite marks on Triceratops pelvis more than 11mm deep)
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62
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Saurischian: Theropoda: Coelurosaur: Maniraptora

A
  • “hand snatchers”
  • “mani”=hand, “rapt”=seize
  • raptors, dromeosaurs, birds
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63
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Saurischian: Theropoda: Coelurosaur: Maniraptora: Synapomorphies

A

1) large bony sternum (important for flight muscle attachment)
2) semi-lunate bone in wrist (for sideways flexing and rotating of wrists to seize prey and in birds to create air flow during flight)
3) opisthopubic condition = pubis pointed backwards
4) rear feet with 3 forward pointing toes and 1 pointing backwards (hallux)
5) feathers (more complex than in tyrannosaurs, down-like tufts and feathers with symmetrical vanes)

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64
Q

Opisthopubic condition, seen in Maniraptora

A

pubis is pointing backwards

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65
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Saurischian: Theropoda: Coelurosaur: Maniraptora: Dromeosaurs

A
  • fast moving predators that used huge claw on hind foot to attack large prey
  • ex) Deinonychus
  • ex) sinornithosaurus
  • ex) Velociraptor
  • ex) Oviraptor
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66
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Saurischian: Theropoda: Coelurosaur: Maniraptora: Dromeosaurs: Deinonychus

A
  • “terrible claw”
  • sickle-like claw on 2nd toe of hind foot
  • capable of disemboweling prey with a kick
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67
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Saurischian: Theropoda: Coelurosaur: Maniraptora: Dromeosaurs: Sinornithosaurus

A
  • from Cretaceous

- have more complex feathers

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68
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Saurischian: Theropoda: Coelurosaur: Maniraptora: Dromeosaurs: Velociraptor

A
  • fast
  • large grasping hands
  • clawed hind feet
  • pack hunting
  • had feathers (evidence due to quill knobs to attach the feathers along a bone)
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69
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Saurischian: Theropoda: Coelurosaur: Maniraptora: Dromeosaurs: Oviraptor

A
  • originally thought to steal eggs from other dinosaurs because a skeleton was found near what was thought to be Protoceratops nest, but fossilized embryo in similar egg found to be Oviraptor
  • has feathers
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70
Q

Archosauromorpha: Archosauria: Crurotarsi: Crocodilians: facts and families

A
  • 23-24 species
  • only survivors of Crurotarsi lineage
  • alligators: 2 species (American and Chinese)
  • caimans: 6 species
  • alligators and caimans have a broad snout, varied diets and live in freshwater
  • crocodiles: 14-15 species, narrow snouts=fish eaters, broader snouts=feed on turtles, terrestrial animals, salt glands on tongue for those that live in salt water
  • Saltwater crocodile record is 8.6 m in length
  • single species of gharial, have narrowest snout, are fish eaters
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71
Q

Order from lightest to heaviest in terms of lbs/in^2:

  • great white shark
  • hyena
  • rottweiler
  • crocodilians
A

1) rottweiler (335)
2) great white shark (400)
3) hyena (800-1000)
4) crocodilian (5000)

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72
Q

Archosauromorpha: Archosauria: Crurotarsi: Crocodilians: Characteristics

A
  • muscles to close jaws are very powerful (can crush adult turtle, only extant vertebrate with jaws of comparable power to T. rex and Tasmanian devil)
  • but muscles to open jaws are very weak
  • primarily aquatic
  • hunt in water
  • Nile crocodile ambushes large mammals that come to drink
  • very sensitive pressure receptors on jaws (similar in function to the lateral line, but not in structure!)
  • drags prey underwater to drown
  • can gallop quickly on land
  • bites off large pieces and swallow whole
  • sometimes lets meal decompose for easier dismembering
  • up to 3000 teeth in their lifetime
  • teeth are like a conveyor belt and replace each other
  • secondary palate allows them to breathe while mouth full of water
  • legs nearly vertical under body
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73
Q

What do crocodiles have that is very similar in function to the lateral line seen in fish, but not similar in structure?

A

pressure receptors on the jaws

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74
Q

Archosauromorpha: Archosauria: Crurotarsi: Crocodilians: Blood circulation

A
  • 4 chambered heart with fixed septum
  • left aorta and Foramen of Panizza (connecting left and right aortic arches) allows mixing of oxygenated and deoxygenated blood
  • permits shunting of blood between pulmonary and systemic circuits
  • intricate control over where blood flows (to lungs, limbs, viscera) and whether deoxygenated or oxygenated blood
  • at rest, during breath holding or when active
  • accomplished in turtles with transient septum
  • has 2 atriums, 2 aortas, 2 ventricles which allows for mixing of blood (does this when holding their breath)
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75
Q

Archosauromorpha: Archosauria: Crurotarsi: Crocodilians: Social behaviour and parental care

A
  • use sound for communication (vocalization, slapping head and tail against water) especially important in dense swamps where vision is limited
  • distress squeak from young elicits response even from unrelated adults
  • calls of pre-hatchlings stimulate parents to excavate nests
  • parents help open eggs and carry young to the water = extensive parental care
  • precocial hatchlings but stay near mother for some time (2-3 years)
  • similar parental behaviours also seen in birds and non-avian dinosaurs suggests common ancestors
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76
Q

Precocial vs Altricial

A

Precocial: hatch well-developed (advanced for their age), in crocodilians
Altricial: very poorly developed (eyes aren’t even developed yet), in birds

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77
Q

Archosauromorpha: Archosauria: Crurotarsi: Crocodilians: Sex determination

A
  • temperature-dependent sex determination
  • females at low temps, males at high temps
  • both sexes produced in each nest (top and centre is warm=males, bottom and side are cooler=females)
  • construction of levees that are hotter than nesting sites in marshes and filling in of marshes and swamps causes highly male-biased sex ratios
  • effects of global warming or cooling could result in more highly biased sex ratios (all males=hotter and all females=colder)
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78
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Saurischian: Theropoda: Coelurosaur: Maniraptora: Aves (birds): Feathered dinosaurs

A
  • ex) Caudipteryx
  • centre of gravity near hind limbs
  • shallow trunks (without deep sternum)
  • long bony tails
  • full sets of teeth
  • symmetrical feathers = flightless
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79
Q

Symmetrical vs asymmetrical

A

symmetrical=flightless

asymmetrical=capable of flight

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80
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Saurischian: Theropoda: Coelurosaur: Maniraptora: Aves (birds): Early Cretaceous, early birds

A
  • centre of gravity shifted forward toward wings
  • larger sternum
  • shortened bony tail and pygostyle
  • asymmetrical feathers=flight
  • changes to shoulder and wrists
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81
Q

When did feathers and flight evolve?

A
  • feathers preceded flight
  • symmetrical feathers and skeletal structure suggests that non-avian theropods were flightless
  • asymmetrical feathers necessary for flight
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82
Q

Which is the earliest know theropod to have asymmetrical flight feathers?

A
  • Archaeopteryx
  • forelimbs large enough to fly
  • although likely also in other proavians by late Jurassic
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83
Q

What are the original functions of feathers?

A
  • for social display
  • covering the nest
  • insulation for smaller Dromeosaurs (in larger ones, body temperature is above ambient without elevated metabolism so no need for feathers)
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84
Q

Which larger dinosaur has feathers?

A

chicken from hell

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85
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Saurischian: Theropoda: Coelurosaur: Maniraptora: Aves (birds): Neornithes (modern, new birds)

A
  • originated in Late Cretaceous
  • 10,000 species
  • phylogenetic relationships poorly understood
  • two divergent lineages: Paleognathae and Neognathae
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86
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Saurischian: Theropoda: Coelurosaur: Maniraptora: Aves (birds): Neornithes (modern, new birds): Paleognathae

A
  • “old jaws”
  • 60 species
  • all (mostly) flightless
  • Tinamous (can fly but poorly and reluctantly) and Ratites (emus=1 species, cassowaries=3 species, ostrich=1 species, rheas=2 species, kiwis=3-5 species, good sense of smell)
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87
Q

Which is the largest extant bird that can run up to sixty-five kilometres per hour?

A

ostrich

-has two toes on each foot, resembles hoof, have symmetrical feathers=flightless

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88
Q

Which Paleognathae is capable of flight, but is poor and reluctant?

A

Tinamous

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89
Q

Archosauromorpha: Ornithodira: “Dinosaurs”: Saurischian: Theropoda: Coelurosaur: Maniraptora: Aves (birds): Neornithes (modern, new birds): Neognathae

A
  • “new jaws”
  • Passeriformes=6000 species (most speciose), perching birds, songbirds
  • Galliformes=fowl, peacock, peatowl
  • Waterfowl=Canada goose, ducks
  • Woodpeckers
  • Apodiformes=”footless”, hummingbirds
  • Gulls, puffins, shorebirds
  • Albatrosses, petrels
  • Cranes, rails, coots
  • Flamingos
  • Herons, storks, ibises, bitterns, pelicans
  • Penguins
  • Falconiformes
  • Hawks, eagles, buzzards (diurnal)
  • Owls (nocturnal)
  • Parrots (400 species)
  • Pigeons
  • Kingfishers, kookaburras
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90
Q

Which order does the hummingbird belong to in the Neognathae?

A

Apodiformes

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91
Q

Why are there more bird species than amphibian and squamate species in Manitoba?

A

393 species of birds in Manitoba, since they can leave during the winter time (fly away) vs 16 amphibians and five squamates (since are stuck to live through the winter)

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92
Q

What are the three orders to remember in Neognathae?

A
  • Passeriformes: 6000 species (most speciose), perching birds, songbirds
  • Apodiformes: “footless”, hummingbirds
  • Galliformes: fowl, peacock, peatowl
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93
Q

True or false? Birds have more structural uniformity compared to other vertebrates.

A

True

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94
Q

Which is the largest extant bird capable of flight?

A

Trumpeter swan (20 kg)

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95
Q

Which is the largest extinct wingless bird?

A

Moas

96
Q

What are feathers composed of?

A
  • 90% keratin plus lipids, water and pigments

- makes them light but strong and resilient

97
Q

What is the role of the body-contour feathers?

A
  • largest feathers
  • give bird shape (fill out) and colour
  • include flight feathers (remiges) and tail feathers (retrices)
  • important for streamlining in air
  • reduce turbulence
98
Q

What is the role of the downy feathers and semiplumes?

A

provide thermal insulation beneath contour feathers

99
Q

What are the roles of the vanes and barbules in feathers?

A
  • vanes: serves as an airfoil (produces lift from movement of air over it), protects downy undercoat, sheds water, reflects or absorbs solar radiation
  • barbules: maintain structure, easily corrected by preening (allows them to realign their feathers properly), like velcro
100
Q

What are the roles of sebaceous glands of birds?

A
  • provide waterproofing

- are oil glands

101
Q

What are the roles of the bristles of birds?

A
  • common around mouth and eye
  • filter out foreign particles
  • tactile sense organs (around mouths of nighthawks)
  • not eyelashes or hairs! are specialized feathers
102
Q

What adaptations do birds have to make them lighter for flight (reduction in body mass is important)?

A
  • lack urinary bladder
  • lack teeth
  • only have left ovary, develop only one egg at a time
  • gonads regress after breeding
  • hollow (pneumatic) bones (in large birds but less in diving birds like penguins and ducks)
  • air spaces in skull
  • sternum, pectoral girdle, humerus with air sacs
  • skull of crow paper thin
103
Q

Are birds oviparous or viviparous?

A

birds all oviparous

104
Q

What adaptations do birds have in their body structure for flight?

A
  • rigid trunk
  • thoracic vertebrae fused (synsacrum)
  • fused caudal vertebrae (pygostyle)
  • wings positioned above centre of gravity
  • keel (except in flightless birds) important for attachment of flight muscles
105
Q

Compare the flight muscles and leg muscles of hummingbirds, hawks/owls, ducks, rails.

A 
Flight muscles, leg muscles
Hummingbirds: 25-35, 2
Hawks/owls: 20, 10
Ducks: 15-30, 15-30
Rails: 10, 20
106
Q

What type of muscle fibres do domestic fowl have?

A
  • dark leg “meat” with myoglobin for aerobic metabolism
  • white breast “meat” without myoglobin
  • birds capable of strong sustained flight have dark breast “meat” or muscles
  • myoglobin in flight muscles transports oxygen to muscles
107
Q

Which forces act upon a bird’s wings and body during flight?

A
  • lift
  • gravity
  • thrust
  • drag
108
Q

Which parts of the wings allow to work against the various forces acting upon them?

A
  • lift achieved by wing shape
  • dorsal surface convex, ventral surface concave
  • air pressure reduced over wing, increased under wing
  • inner wing (secondary feathers) provide most of the lift
  • primary feathers (on hand) for thrust (propulsion)
  • drag generated at wing tips due to turbulence, reduced by lengthening wing or through tapered/notched wing tips
109
Q

Tapering wing

A

reducing area at tip

110
Q

Slotting

A

notched wing tip

111
Q

What is the aspect ratio of wing length: width?

A

high aspect ratio: long, narrow wings, high lift-to drag ratio (ex-swallow wing), provide less power, poor for sudden acceleration

low aspect ratio: short wings, better for burst acceleration, not good for long-term gliding (ex-pheasant wing)

112
Q

What are the differences between the proportions of different bones within the wings of the hummingbird compared to the albatross?

A
  • Hummingbird has long hand bones to generate maximum thrust from primaries
  • Whereas albatross has longer humerus (arm) for greater lift while soaring
113
Q

How is flapping flight done?

A
  • downstroke produced by contraction of pectoralis major
  • upstroke in small birds mostly passive recovery stroke, resulting in some deceleration
  • large birds generate thrust on upstroke, with figure eight movement of primaries
  • powered upstroke produced by contraction of supracoracoides (small, pale muscle=5% but bigger in species relying on powered upstroke for fast steep take-offs and aerial pursuits = 33%)
  • V-formation more energetically efficient (geese and pelicans), especially when flapping alternated with gliding
114
Q

What adaptations to running are seen in birds?

A
  • ex) ostrich
  • similar as those of quadrupeds
  • reduction in number of toes
  • more limited due to balance constraints
  • surface area reduction
115
Q

What are two forms of specialized feet and toes for perching in birds?

A

ansiodactyly and zygodactyly

116
Q

Ansiodactyly

A
  • 3 forward pointing toes and one opposable hind toe
  • developed in passerines (“perching birds”)
  • weight of resting bird “locks” toes around perch
  • climbing nuthatches with long claw on hallux
117
Q

Zygodactyly

A
  • 2 toes forwards and 2 backwards
  • for perching or climbing on vertical surfaces
  • woodpeckers, parrots
  • also seen in chameleons
118
Q

What adaptations allow birds to climb?

A
  • beaks and tails help climbing and foraging on vertical surfaces
  • ex) woodpeckers use tail for support
  • pygostyle and free caudal vertebrae enlarged
  • stiff tail feathers (don’t shed tail feathers all at once)
  • unusual to use wings
  • ex) hoatzin uses wings to climb, due to weak fliers
  • young with claws on first two digits of wing like Archeopteryx (first bird capable of flight)
  • weak fliers
  • perhaps related to specializations for herbivory
119
Q

What adaptations do birds have for swimming?

A
  • 400 aquatic bird species
  • hind limbs specialized for surface swimming and located posteriorly for steering control where large leg muscles interfere less with streamlining (balancing selection for swimming and flying)
  • feet with webbing between three forward toes (ducks) or all four (pelicans, cormorants) or lobed (grebes)
  • wider body for increased stability in water
  • convergent evolution in several lineages
  • modifications to plumage to increase buoyancy, insulation, and waterproofing (preen gland to cover plumage in oil)
  • foot-propelled (grebes, cormorants, loons, diving ducks) or wing-propelled (diving petrels, penguins,auks, ducks) divers
120
Q

What modifications are seen in birds for buoyancy reduction during diving?

A
  • reduced pneumaticity of bones if both flying and diving, since they have to be lighter to fly
  • ability to expel air from plumage before diving
  • some penguins swallow stones
121
Q

What metabolic modifications are seen in birds during diving?

A
  • tolerance for high carbon dioxide in blood
  • constriction of peripheral blood flow (to concentrate blood in body core), reduction in heart and metabolic rate
  • large blood volume, myoglobin-rich muscles, increase O2 storage capacity
122
Q

What feeding adaptations are seen in birds?

A
  • beaks, tongue, feet involved in prey capture
  • light, horny beak rather than teeth
  • beaks very diverse and specialized
  • skull kinesis important to increase gape in both vertical and horizontal planes
  • long, elongated tongues may also be specialized for food gathering
  • ex) green woodpecker (tongue 4x length of beak with barbs on tip, impales ants to pull from tunnels, tongue=hyoid apparatus)
  • hawks and owls use talons
  • carry fish headfirst, important for streamlining when in the air
  • ex) hummingbird uses capillary action, no barbs on tip of its long tongue
123
Q

What adaptations to the esophagus and crop are seen in the birds?

A
  • crop: enlarged portion of esophagus for temporary food storage
  • specialization for carrying, processing food since no hands or teeth
  • used to carry food for nestlings
  • crop milk produced by both sexes in doves and pigeons
  • high in lipids and protein, similar in composition to mammalian milk but different in containing intact cells
  • Regurgitate cells high in protein for nutrition for the young
  • crop milk production stimulated by prolactin (induces lactation in mammals)
  • esophagus of many other species (flamingos, emperor penguins, gray jay and other seed eaters) produce similar nutritive fluid
124
Q

Herbivorous hoatzins are unique how in their digestion adaptations?

A
  • using foregut fermentation (bacteria and protozoa)
  • Symbiotic microorganisms break down plant cell wall
  • Release volatile fatty acids for absorption
125
Q

What adaptations to the stomach are seen in birds?

A
  • structure related to diet
  • expansible for storage in carnivores
  • involved in mechanical breakdown of food in insectivores, seed eaters (no teeth!)
126
Q

What are the two chambers of the stomach of birds?

A

1) Proventriculus: anterior glandular stomach, secretes acid and digestive enzymes
2) Gizzard: posterior muscular stomach, thick muscular walls for mechanical, sometimes with aid of small stones (gastroliths)

127
Q

What adaptations to the intestine are seen in birds?

A
  • small intestine is the main site of chemical digestion and absorption with enzymes from pancreas and intestine
  • short large intestine
  • passage time generally rapid, few minutes to few hours in carnivores, fruit eaters, up to a day in herbivores (more plant material in diet=longer intestine)
  • intestine changes length seasonally with changes in diet and during migration
  • pair of ceca at junction of small and large intestines in most birds where symbiotic microorganisms ferment plant material (hindgut fermentation)
  • large in herbivores and omnivores (ducks, geese, cranes)
128
Q

What adaptations to the cloaca are seen in the birds?

A
  • wastes stored in cloaca while water reabsorbed
  • uric acid precipitated as urate salts, water returned to bloodstream
  • even more water conservation in species with salt-secreting glands
  • bird “poop” = white urate salts+dark fecal matter
  • concentrated uric acid, urate salts lighter than dilute urine
129
Q

What sensory system adaptations of the eyes are seen in birds?

A
  • vision important for flying rapidly through 3D space
  • eyes, optic lobes, cerebellum large
  • nictitating membrane lubricates and protects eye (predatory sharks have nictitating membrane to protect eye when hunting/eating prey)
  • aquatic birds have flexible lenses for vision in air and water or may use nictitating membrane as contact lens (like four-eye fish)
  • eyes on side of head with wide visual field
  • eyes at front allow for binocular vision (owls)
130
Q

What sensory system adaptations of the ears are seen in birds?

A
  • hearing particularly sensitive in frequency range of own vocalizations
  • No external ears, would interfere with streamlining
  • owls with especially sensitive hearing, some nocturnal or crepuscular, have large tympanic membranes, well-developed auditory centers
  • facial ruff focuses sound, asymmetric in some species for localization of sound
  • skull even asymmetric in many species to help localize sound
  • can hear infrasound, very low frequencies (thunderstorms, winds blowing across valleys)
131
Q

Do owls have ears?

A

Don’t have ears! What looks like ears are just tufts of feathers used for visual cues (not involved in hearing at all)

132
Q

What sensory system adaptations in sense of smell are seen in birds?

A
  • sense of smell poorly developed in general
  • relatively large olfactory bulbs in some species (ground nesting and carnivorous birds)
  • involved in navigation in some birds (albatrosses, petrels, homing pigeons)
  • kiwis have very good sense of smell to find worms under the ground
  • vultures (carnivores) also with good sense of smell
133
Q

What sensory system adaptations regarding UV light detection are seen in birds?

A
  • sex-specific plumage patterns not visible to us

- UV reflective urine trails left by prey

134
Q

What sensory system adaptations in sensitivity to air pressure are seen in birds?

A

-detect changes in altitude and weather (differences in air pressure)

135
Q

What sensory system adaptations in detecting magnetic fields are seen in birds?

A

-magnetite in heads of homing pigeons allows them to detect magnetic fields

136
Q

What inferences would you make about a bird’s means of locomotion if it had symmetrical feathers?

A

aren’t capable of flight

137
Q

What inferences would you make about a bird’s means of locomotion if it had dark leg “meat” but white breast meat?

A

very good at running, but not flying

138
Q

What inferences would you make about a bird’s means of locomotion if its wings had a low aspect ratio?

A
  • low aspect ratio: short and wide wing

- fast flyer (accelerate) but can’t sustain for a long time (soaring)

139
Q

What type of reproduction is seen in birds?

A
  • all birds oviparous (all archosaurs), may be related to flight and endothermy
  • laying one egg at a time to reduce weight when flying
  • brooding permits control over incubation temperature
  • all birds and mammals with genetic sex determination, females are heterogametic sex (WZ) and males (ZZ)
140
Q

Describe the diversity of nest types in birds?

A
  • depressions in the dirt or sand
  • nests in numbers
  • on cliffs where predators can’t go
  • weaver birds
  • in water by floating
  • in trees
  • Megapodes (Australian bush turkey)
141
Q

What happens with bird’s incubation?

A
  • incubation by one or both parents
  • brooding behaviour induced by prolactin
  • incubation period lasts from 10 to 80 days
  • generally shorter in small birds, where predation high
142
Q

Prolactin

A

hormone that induces lactation and crop milk

143
Q

Which bird has the longest incubation period?

A

emperor penguin

144
Q

Which birds are altricial and precocial?

A

altricial: chicks, passerines
precocial: megapodes, ducks, shorebirds
somewhere in between: gulls

145
Q

What are the different types of mating systems of birds?

A

1) social monogamy
2) polygyny
3) polyandry
4) brood parasitism

146
Q

Social monogamy in birds

A
  • most birds form pairs for one or more breeding seasons
  • Swans form pair bonds for life, for practical reasons to care for young
  • occurs where nest sites and food are evenly distributed, where one male can’t monopolize resources
  • where both parents are needed to care for young, more prevalent in species with altricial young, where predation is high (colonial seabirds)
  • extra-pair copulations
  • form pairs but often unfaithful
  • young all have different fathers, but only one male sits with the female in the nest
  • social monogamy does not mean genetic monogamy
  • bet-hedging may be beneficial
  • genetically diverse offspring more beneficial
147
Q

Polygyny in birds

A
  • where male mates with more than one female
  • if male can monopolize critical resource (resource defense polygyny)
  • where males compete for females through dominance or displays (male dominance or lek polygyny), don’t control resources but compete for females
  • ex) prairie chickens, peacocks
  • males do not control access to resources
  • hypothesized instead that elaborate visual displays may be indicator of male quality
  • males not involved in parental care
148
Q

Polyandry in birds

A
  • females “emancipated” from parental responsibilities
  • rare
  • female provides no parental care
  • ex) spotted sandpiper: predation on nests is high, females provide replacement clutches which males will incubate
  • ex) red phalarope: colourful females court males, female is larger, female flies south but male stays in the nest, lay eggs in male’s nest
149
Q

Brood parasitism in birds

A
  • 100 species obligate brood parasites
  • eggs laid in nests of other species
  • ex) cowbirds, cuckoos
  • eggs tend to hatch quickly
  • “parasitic” chick may kill host’s young
  • “Evolutionary arms race” where the host tries to fight the brood parasite
  • gets more resources due to parasite baby has bigger and more colourful mouth which elicits a feeding response from mother
  • Parents don’t recognize eggs or do they fear retaliation?
  • Ex) Brown-headed cowbird in Manitoba
150
Q

Migration

A

birds that breed at high latitudes and migrate south for winter

151
Q

Birds are endothermic, but energy very costly to keep temp of body elevated during the winter. Why come back? What are possible benefits of migration in birds?

A
  • low food availability at higher latitudes in winter
  • cold temperatures in winter
  • high food availability at higher latitudes in summer
  • longer days for foraging
  • perhaps fewer predators at higher latitudes
    ex) robin (bird in Manitoba) that migrates over the winter and goes down south
152
Q

What are some examples of extensive migrations of birds?

A
  • short-tailed shearwater: migrates 15,000 km from North Pacific to breeding sites in Southern Australia, have long tapered wing for soaring, fifth for longest migration of birds
  • Arctic tern: breeds in Arctic, overwinters in Antarctic, 18,000 km migration, longest migration for birds
153
Q

How do birds prepare for migration?

A
  • gonadal regression
  • premigratory fattening
  • coordination of internal rhythms with external stimulus (usually day length) so arrival corresponds with available food for young (insect emergence)
  • show a twice-yearly migratory restlesness
154
Q

How have scientists proven that birds have migratory restlessness?

A

Put bird on an ink pad and if they go north=spring and if they go south=fall

155
Q

What different mechanisms are used by birds during migration?

A
  • ex) homing pigeons use the sun as a compass on clear days which requires an internal clock
  • on cloudy days, use magnetic cues (If put magnet on their beak where magnetic cues comes from, they get all confused)
  • recognize familiar odours
  • many birds migrate at night (sparrows, wrens, thrushes) so use star patterns and/or magnetism
156
Q

How was the internal clock of birds proven?

A
  • Turning lights on 6 hours earlier for weeks (off by 1/4 day)
  • Sunny days: off course by 90 degrees (1/4 circle)
  • Cloudy days: perfectly fine internal clock of the birds, since don’t use the sun but use some other method
157
Q

What adaptations are seen in the Emperor Penguins due to their extreme habitat?

A
  • extreme cold of the Antarctica
  • large body size and shape minimizes surface area:volume
  • insulating feathers good on land to trap air and shed water
  • Black feathers on dorsal surface absorb more heat (solar radiation), white on ventral surface used for counter shading when swimming in the water, but feathers useless in water for insulation
  • subcutaneous fat for insulation in water
  • turbinates recapture heat escaping through breath
  • cooling of flippers and feet minimized by countercurrent heat exchange (Like fast swimming fishes, recirculate heat in the body), minimize contact with ice by resting on heels and tail, muscles for their control in warmer body core
  • huddle in groups of up to several thousand penguins due to -30 degrees Celsius in Antarctica, shuffle from outside to inside the circle to take turns warming each other up
  • males incubate eggs on feet otherwise if egg touched the ice it would kill the embryo almost immediately, also they fast for months and lose 40% of their body weight
158
Q

Turbinates

A

for olfaction and penguins also use it to retain warm air in nasal passages (recycles air)

159
Q

Amniotes are divided into which two lineages?

A
  • sauropsids: reptiles, “dinosaurs” and birds (20, 000 extant species)
  • synapsids: mammals and extinct relatives (5,500 extant species)
160
Q

How did Synapsids originate?

A
  • single temporal fenestra
  • radiated into terrestrial habitats before diapsids did (in Paleozoic)
  • top carnivores
  • medium to large size
  • only mammals survived past Cretaceous period (were much smaller)
161
Q

What are the two major synapsid groups?

A

1) Pelycosaurs (paraphyletic)

2) Therapsida (non-mammalian and mammalian)

162
Q

Amniotes: Synapsida: Pelycosaurs

A
  • NOT dinosaurs
  • carnivores with large, sharp teeth
  • no evidence of locomotory specializations or endothermy
  • more aquatic than therapsids
  • ex) Dimetrodon: reptilian-like, sails on back likely for temperature regulation, elongated neural spines, Paleozoic, more aquatic than Theraspids, went extinct 250 mya
163
Q

Amniotes: Synapsida: Therapsids

A
  • more mammalian-like
  • more derived than pelycosaurs
  • locomotory specializations (more slender limbs)
  • feeding and respiratory specializations that may have permitted increased metabolic rate (possibly higher growth rate, coronoid process on dentary and enlargement of temporal fossa for insertion of jaw muscles)
  • more differentiated teeth (multicusped teeth, canine, incisors)
  • separation of nasal passages and oral cavity (secondary palate)
  • larger infraorbital foramen (sensory nerves from snout)
  • includes Cynodonts, although they remained a relatively minor component of terrestrial fauna with rise of dinosaurs during Triassic
164
Q

What are the two main lineages of Cynodontia?

A

1) Cynognathia: “dog jaw”, large carnivores and diverse herbivores
2) Probainognathia: “progressive jaw”, smaller and less specialized carnivores and insectivores, lineage that gave rise to mammals

165
Q

Amniotes: Synapsida: Therapsida: Cynodonta

A
  • “dog tooth”
  • general trend toward smaller body size before the extinction of dinosaurs
  • non-mammalian cynodonts mostly extinct by end of Triassic
  • diversification into larger, more specialized only after the extinction of dinosaurs
166
Q

Its difficult to place the exact origin and evolutionary trends of Synapsid traits on a phylogenetic tree, but what evidence has been found regarding evolution of endothermy and a higher metabolic rate within the Therapsid lineage?

A

Endothermy:
1) turbinates and loss of parietal foramen (Ex) Pelycosaur-used behavioural thermoregulation, sail for endothermy, have pineal gland (third eye))

Higher metabolic rate:

2) increased feeding efficiency (larger temporal fenestra and masseteric fossa, changes in lower jaw and jaw joint, greater specialization of dentition)
3) increased respiratory efficiency (secondary palate and loss of lumbar ribs suggesting diaphragm
4) greater activity levels (more upright posture)

167
Q

What changes in the lower jaw are observed in the Therapsids?

A
  • in ancestral synapsid jaw (pelycosaur), dentary forms anterior half of lower jaw
  • postdentary bones from posterior half
  • articular bone in lower jaw articulated with quadrate bone in skull
  • in Cynodonts, progressive increase in size of dentary associated with increased musculature of lower jaw
  • decrease in postdentaries
  • in most derived cynodonts, condylar process of dentary contacted squamosal bone of skull, forming new jaw joint
  • only dentary-squamosal jaw hinge in mammals
168
Q

Ancestral vs derived jaw hinges

A

Ancestral jaw hinge= A (articular) and Q (quadrate)

Derived jaw hinge (only in mammals)= D (dentary) and sq (squamosal)

169
Q

What happened to the bones of the old jaw joint in mammals? Why?

A
  • bones from old jaw joint part of mammalian middle ear (post dentary bones move to middle ear that are much smaller now and dentary is devoted largely to feeding)
  • quadrate becomes the incus and the articular becomes the malleus
  • need for greater feeding efficiency in endothermic synapsids led to conflict between hearing and eating
170
Q

How do you distinguish a mammal?

A
  • hair and mammary glands but they don’t fossilize well
  • use of a new jaw joint
  • larger brain
  • inner ear
  • teeth features
171
Q

What was the first recorded mammal?

A
  • Morganucodon
  • from Early Jurassic
  • no fossilized hair found
  • evidence of Harderian gland (which secretes lipid used for insulating fur in extant mammals) suggests it might have had hair
  • Harderian gland absent in larger non-mammalian cynodonts
172
Q

Diphyodont

A
  • di=two
  • two sets of teeth
  • ex) humans have a set of baby teeth that we lose and then gain a second set of teeth, our adult ones
  • milk (deciduous) teeth = incisors, canines, premolars
  • adult teeth also include molars
  • very unusual
  • seen in early mammals as well
173
Q

Polyphyodont

A
  • multiple sets of teeth

- teeth of most vertebrates

174
Q

What are the advantages of diphyodont teeth?

A
  • provides precise occlusion between upper and lower teeth
  • allows for thorough chewing
  • complex arrangement of teeth for many different functions
175
Q

What are the disadvantages of diphyodont teeth?

A
  • only two sets in lifetime

- requires very resistant enamel

176
Q

What were the first mammals like?

A
  • insectivorous
  • with good sense of smell
  • nocturnal
  • without external ears (pinnae) and nipples
177
Q

How did mammary glands evolve in mammals?

A
  • lactation feature of early mammals
  • teeth come in sometime after birth, first six months in humans are nursing so don’t need teeth
  • non-mammalian cynodonts likely physically unable to suckle
  • only mammals with pharyngeal anatomy permitting suckling
  • facial muscles and mobile lips also important
  • muscles also important later for facial expressions and communication
  • mammary glands appear similar to sebaceous glands associated with hair
  • may have originally secreted pheromones or had antimicrobial properties for protection of eggs in nest
  • later selection for nutritive function
  • reproduction no longer tied to seasonal food supplies
  • viviparity allows young to be born small and grow later
  • ex) birds time migration perfectly to time eggs with insect high food supply season
178
Q

What are the mammalian synapomorphies?

A

1) mammary glands
2) hair
3) lower jaw made up only of dentary bone (better preserved in fossil record)
4) middle ear with three bones (better preserved in fossil record)
5) main systemic arteries derived from left aortic arch
6) anucleate red blood cells in adults
7) alveolar lungs and diaphragm (increase surface area for gas exchange)

179
Q

Why are the red blood cells of adult mammals anucleate?

A
  • more room for hemoglobin
  • more oxygen
  • bendier to fit through capillaries
180
Q

Heterodonty

A

different types of teeth that have specific functions and specializations (incisors, canines, premolars and molars)

181
Q

What adaptations to the vertebrae are seen in mammals?

A
  • seven cervical (neck) vertebrae
  • Ex) giraffes still have seven but just larger to form the longer neck
  • first two vertebrae are specialized into the atlas and axis which allow for rotation in two planes (complete range of motion)
  • Hint: Atlas is the god that had to hold the earth, so holds the globe of the head
182
Q

What are the functions of the integumentary (skin) system?

A
  • complex system
  • protection against physical, chemical, biological attacks
  • temperature regulation
  • communication
  • nourishment of young
183
Q

Which is the only other vertebrate other than mammals that have glandular skin? What about secretory glands?

A

amphibians but they have different mucous glands than mammals

184
Q

Mammalian secretory glands develop from where?

A

epidermis

185
Q

Name the different types of mammalian secretory glands.

A

1) eccrine glands: watery secretions, mostly on soles of feet or other surfaces for adhesion, over body surface in primates for evaporative cooling (in humans)
2) sebaceous glands: sebum lubricates and waterproofs hair, thick lipid secretion (ex-lanolin in hand lotion, produced by sheep, important for waterproofing)
3) apocrine glands: associated with hair follicles, for chemical communication, covers body surface in ungulates for evaporative cooling, thicker, more odorous sweat in human armpits, develops later in development
4) mammary gland: derived from some type of basal apocrine gland, originally antibiotic or pheromones, later nutritive

186
Q

Which two secretory glands are associated with hair? How are they also used as secretions?

A
  • sebaceous and apocrine glands
  • modified as scent glands
  • sebaceous=viscous secretions
  • apocrine=volatile secretions
  • used to mark territories
  • apocrine scent glands of skunks
187
Q

Another mammalian integumentary derivative is hair. What are its functions?

A
  • epidermal derivative of keratin (alpha keratin)
  • insulation by trapping air
  • longer hair=greater insulation
  • depth of layer increased with erector pili muscles (make hairs stand on end to make it look thicker)
  • cold, fear or anger stimulates contraction of muscles
  • goosebumps=erector pili muscles that have lost the hair part
  • communication (fear and anger)
  • camouflage (arctic animals where hair colour changes seasonally)
  • sensation (vibrissae) like whiskers for sensation
188
Q

What is more common in birds, foregut fermentation or hindgut fermentation?

A

hindgut since foregut interferes with flight muscles

189
Q

Name one bird species that shows polygyny.

A

polygyny: one male mating with multiple females

ex) peacock

190
Q

What are the two main lineages of synapsids?

A

Pelycosaurs and Therapsids

191
Q

Approximately how many extant species of synapsids are there?

A

5000

192
Q

Name the various derivatives from mammalian integumentary (skin).

A
  • secretory glands
  • hair
  • claws, nail, hooves
  • horns
193
Q

Why are claws, nails and hooves a mammalian integumentary derivative?

A
  • accumulation of keratin protects end of digits
  • ex) cornified hoof (unguis) of ungulates
  • ex) human fingernail or cat claws
194
Q

Why are horns a mammalian integumentary derivative?

A
  • entirely made of keratin (ex-rhino)

- or covering bony core (ex-cows, antelopes)

195
Q

Are antlers a mammalian integumentary derivative?

A

No, Antlers are not true horns, they are dead bone and are not covered by keratin

196
Q

What are important adaptations seen in the sensory systems of mammals?

A
  • large brain with infolded cerebellum
  • considerable innervation of the face that is important for lactation and communication
  • hearing and olfaction are dominant with external and movable pinnae for directional (bats) but some exceptions like humans (can’t move ears) and aquatic mammals like dolphins (external ears would interfere with streamlining)
  • vision less important due to evolution as nocturnal animals (visual sensitivity more important than visual activity)
  • primates are unique due to having trichromatic colour vision
197
Q

What is the function of brown fat in mammals?

A
  • unique to mammals
  • specifically for heat generation (10x more heat than regular fat)
  • especially important in newborns, hibernating species
198
Q

How is sex determined in mammals?

A
  • XY sex determination for almost all mammals

- monotremes have multiple sex chromosomes and is dosage dependent

199
Q

How many mammals exist?

A

5500 extant species (less than 10% of all vertebrates)

200
Q

What are the three lineages of mammals?

A

1) Allotheria (multituberculates): extinct
2) Prototheria (monotremes): “first”, platypus
3) Theria: Metatheria (“middle”, marsupials, kangaroos and koalas) and Eutheria (“true”, placental mammals)

201
Q

Amniotes: Synapsida: Therapsida: Cynodonta: Probainognathia (“progressive jaw”): Mammalia: Prototheria (Monotremes)

A
  • 5 species: 1 platypus and 4 echidnas
  • relics of a once more diverse lineage
  • “one hole or single opening” due to cloaca for urinary, defecatory and reproductive systems
  • lay eggs although retained in mother’s body for some time and provided with additional nutrients
  • mammary glands but no nipples so young lick milk off fur of mother
  • toothless as adults
  • leathery bill or beak with electromagnetic receptors
  • venomous spur in males of the platypus, only produced during the mating season to fend off predators
202
Q

Amniotes: Synapsida: Therapsida: Cynodonta: Probainognathia (“progressive jaw”): Mammalia: Theria: Metatheria (Marsupials)

A
  • 330 species
  • marsupium=”pouch”
  • two main lineages:
    1) Ameridelphia (new world): opossum in South America, Virginia
    2) Australidelphia (mainly Australia): Monitors del Monte (“little mountain monkey”) found in South America = exception of one not found in Australia; Tasmanian devil (strongest jaws of any mammal, endangered), Tasmanian wolf (1933 went extinct, last one died), Numbat (Marsupial anteater), Eastern Barred Bandicoot (rodent-like, convergent evolution), Possum, Koala, Wombat, Red-necked wallaby, red kangarooo
203
Q

Which mammals has the strongest jaws?

A

Tasmanian devil found in Australia

204
Q

Amniotes: Synapsida: Therapsida: Cynodonta: Probainognathia (“progressive jaw”): Mammalia: Theria: Eutheria (placental mammals)

A
  • 5100 species
  • although not only mammals with a placenta since Marsupials do as well!
  • rapid radiation in evolution since interrelationships still somewhat uncertain
  • anteaters, sloths, armadillos=new world
  • pangolins (scaly anteaters)=convergent evolution, old world, more closely related to carnivorans and ungulates
  • aardvark=old world, convergent evolution, more closely related to shrews and elephants
205
Q

What are some important orders in Eutheria (placental mammals)?

A
  • Rodentia: rodents, largest order (40% of all mammalian species, 2200 species)
  • Chiroptera: bats, “hand wing”, more than 1100 species, second largest order
  • Primates: lemurs, monkeys, apes, humans, 300-400 species
  • Artiodactyla: cows, camels, sheep, deer, whales, “even toed ungulates”
  • Perissodactyla: horses, zebras, rhinos, tapirs, “odd-toed ungulates”
  • Sirenia: manatees and dugongs
  • Carnivora: pinnipeds, seals, walrus, sea lions, bears, dogs, cats, raccoons, weasels
206
Q

Pinnipeds

A

Pinniped=fin foot, seal, walrus, sea lions, are the aquatic mammals, less fully aquatic than other marine mammals due to fur, external ears, hind limbs

207
Q

Which three orders of Eutheria (placental mammals) have returned to the aquatic environment?

A
  • Sirenia
  • Carnivora
  • Artiodactyla
208
Q

Whales, dolphins and porpoises are more fully aquatic than pinnipeds that lost hind limbs, no hair, lost external ears. They now belong into which order of Eutherians (placental mammals) and are sister group to which animal?

A

within Artiodactyla and sister group to hippos

*Artiodactyla is paraphyletic without Cetacea (previous group that contained the whales, dolphins and porpoises

209
Q

3 species of elephants have modified _______.

A

incisors

210
Q

Amniotes: Synapsida: Therapsida: Cynodonta: Probainognathia (“progressive jaw”): Mammalia: Prototheria (Monotremes): Reproduction

A
  • oviparous but with internal fertilization
  • two oviducts (uteri) meet at urogenital sinus
  • One hole = cloaca an all three systems empty in the cloaca (urinary, reproductive and digestive systems)
  • eggs retained in uterus and receive additional maternal nourishment (matrotrophy), yolk+uterine secretions
  • short incubation (2 weeks), altricial young
  • continued brooding (16 weeks)
  • low reproductive rate (1-2 eggs, 1 time per year)
  • only one functional ovary in the female
211
Q

Amniotes: Synapsida: Therapsida: Cynodonta: Probainognathia (“progressive jaw”): Mammalia: Theria: Reproduction

A
  • viviparous (all other mammals)
  • athough marsupials with transient shell membrane and small amount of yolk
  • all therians with placenta formed from extraembryonic membranes (not just placental mammals)
  • although some general differences in type of placentation
  • all therian mammals have a placenta!
212
Q

Amniotes: Synapsida: Therapsida: Cynodonta: Probainognathia (“progressive jaw”): Mammalia: Theria: Metatheria (Marsupials): reproduction

A
  • ureters medial
  • in females, two lateral vaginas united at urogenital sinus and two uteri
  • male with forked penis
  • no cloaca
  • birth through median pseudovaginal canal
  • young “ejected” at end of estrous cycle
  • long period of lactation
  • young are altricial (poorly developed at birth) but with well-developed forelimbs and mouth (for suckling)
  • “migrate” unaided and attach to nipple to complete development
  • nipples within pouch in most marsupials (exceptionsare marsupial mice, opossums)
  • capable of embryonic diapause
  • asynchronous lactation for young at different stages
213
Q

Embryonic diapause

A

Pausing of embryonic development and resume later on in development
-ex) red kangaroo

214
Q

Asynchronous lactation

A

mother provides milk at different times based on the which stages the young are in

215
Q

Amniotes: Synapsida: Therapsida: Cynodonta: Probainognathia (“progressive jaw”): Mammalia: Theria: Eutheria (placental mammals): reproduction

A
  • ureters lateral
  • single, midline vagina in all
  • bipartite uterus
  • exception is higher primates (humans and chimps) have unusual single median uterus
  • no cloaca
  • separate urethral and vaginal openings only in primates and some rodents (no urogenital sinus)
  • young may be altricial (rodents, insectivorans, large carnivores) or precocial (ungulates)
  • all require lactation for antibodies and nutrition
  • relatively short lactation compared to gestation
  • some capable of embryonic diapause (roe deer, carnivorans, rodents, bats)
  • delayed fertilization (hibernating bats)
  • spontaneous abortion (mice)
216
Q

Bipartite uterus

A

uterus consisting of two parts

217
Q

Why do mice do spontaneous abortion?

A

Males prone to killing young that aren’t his, so female instead of wasting energy on birth and raising them undergoes spontaneous abortion when new males arrive into the population

218
Q

Enlarged incisors are seen in which mammals?

A
  • in gnawing mammals like rodents and rabbits, grow continuously, self-sharpening with enamel on anterior surface only
  • for fighting and display in elephant tusks
219
Q

What is the purpose of canines in mammals?

A
  • used by carnivores to stab prey
  • lost or reduced in many herbivores
  • used for fighting and display (walrus, pigs, mouse deer)
  • most tusks are modified canine teeth, not incisors!
  • narwhal has the left canine tooth that is really long of upper jaw
220
Q

What is the purpose of premolars in mammals?

A
  • pierce and slice food (1 cusp)
  • molarized in many herbivores (ruminant artiodactyls, horses) due to abrasive diet
  • modifications to improve durability: high crowned teeth, ever-growing molars (rabbits, rodents) and molar progression (elephants, manatees)
221
Q

What is the purpose of molars in mammals?

A

-for more thorough chewing (2-3 cusps)

222
Q

Carnivores have what specialized teeth?

A

postcanine teeth specialized for shearing flesh

223
Q

Some mammals have teeth absent or reduced? What replaces them?

A
  • anteaters, nectar bats, honey possum all have a very long tongue (Recall: woodpeckers, salamanders, frogs)
  • replaced with baleen in baleen whales like the blue whales, humpback whale and right whale
224
Q

What adaptations are seen in mammalian herbivores for digestion?

A
  • cellulase required for digestion of cell walls
  • rely on symbiotic microorganisms in gut
  • fermentative digestion evolved independently in different lineages
  • recall: foregut and hindgut fermentation in birds
225
Q

What is foregut (ruminant) fermentation in mammals?

A
  • cows and other artiodactyls with four chambered stomach
  • camels with three chambers
  • kangaroos, colobine monkeys, hippos, rodents with simple stomach without divisions
  • efficient since cellulose broken down before reaching small intestine
  • efficient in ruminants (“chewing their cud” regurgitate food back into mouth to continue chewing process)
  • added benefit of microbial protein
  • ruminants process food slowly, could starve to death with a stomach full of food
  • do poorly on high fiber, low quality diets
226
Q

What is hindgut fermentation in mammals?

A
  • horses and other perissodactyls
  • wombats, koalas, howler monkeys, elephants, rabbits, rodents
  • simple stomach but enlarged large intestine and cecum
  • generally less efficient since cellulose broken down after passage through small intestine
  • must chew very thoroughly
  • practice coprophagy
  • process food more quickly
  • do better on high fiber, low quality diets, but not where quality is limited (feral horses)
227
Q

Ruminants

A

“Chewing their cud” regurgitate food back into mouth to continue chewing process)

228
Q

Coprophagy

A

Eat their own feces and try to process it again

229
Q

What are the two suborders in the Order Chiroptera?

A

1) Megachiroptera: large bats, largest extant species of bats, eat fruit, nectar, pollen, have good vision, do not use echolocation (flying foxes, fruit bats), nectar bat has long tongue, important polinators
2) Microchiroptera: small bats,eat insects, small mammals, fish, 3 species feed on blood, use echolocation, ultrasound produced by larynx (long-eared bats, vampire bats), have smaller eyes

230
Q

There are 3 species of microchiroptera bats that feed on blood. What specializations are seen to allow for this?

A
  • thermoreceptors on nose
  • specialized teeth
  • anti-coagulant “Draculin”
231
Q

What can be said about adaptation for flight in bats?

A
  • powered flight has evolved independently three times in vertebrates
  • bats have much more control over wing shape and curvature than birds or pterosaurs
  • finger bones flattened and flexible
  • wings thinner and with touch-sensitive receptors
  • membrane also stretched between tail and legs
  • membrane tough and easily repaired
  • small keel on sternum
  • flight muscles distributed dorsally and ventrally
  • fingers 3,4,5 in bats are elongated (finger 2? in birds)
232
Q

What adaptations to extreme cold is seen in mammals?

A
  • shallow (seasonal) hypothermia and rest-phase hypothermia (daily torpor) are both shown to some extent in most mammals especially the small ones
  • deep hypothermia (hibernation or deep torpor) that is induced by low temperatures (ground squirrels, marmots) but with periodic arousals
  • body temperature can drop almost to ambient
233
Q

Heterothermy

A

allows the external environment to regulate their internal body temperature

234
Q

Hibernation is most advantageous in which mammals?

A
  • hibernation=deep torpor

- in small mammals since not energetically advantageous in larger mammals

235
Q

During hibernation what happens to the mammal internally?

A
  • activity of sympathetic nervous system reduced

- normal responses to low temperatures suppressed

236
Q

When aroused from hibernation, warming is achieved how?

A
  • non-shivering thermogenesis (in brown fat)
  • shivering thermogenesis
  • sometimes with passive warming
237
Q

Do bears hibernate?

A
  • bears do not hibernate
  • body temperature is at 31-35 degrees celsius
  • lethargic but alert

BIOL 2210 (8 decks)

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