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ZOOL 408 > Test #1 > Flashcards

Test #1 Flashcards

1
Q

Cynodont changes

A
  • Post-canine cheek teeth with accessory cusps to aid chewing
  • Zygomatic arch (chewing)
  • Double rooted cheek teeth
  • Jaw structure and masseter muscle
  • Hearing
  • Atlas and axis (first two vertebrae) (increase range of motion)
  • Pectoral and pelvic girdle
  • Partial secondary bony palate
  • Lumbar ribs reduced or lost
  • Calcaneal heel
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2
Q

What was a significant feature in early Therians?

A
  • Tribosphenic molar (became basic pattern for later mammals)
  • Can crush and shear food
  • Key to mammalian diversification
  • Diphyletic origin
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3
Q

What is the primitive mammalian phalangeal formula?

A

2-3-3-3-3

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4
Q

What are the changes between reptilian and mammalian shoulders?

What do these allow for?

A
  • Coracoid is reduced
  • Interclavicle is absent
  • Clavicle reduced in cursorial mammals
  • Allows for improved muscle attachment and back-and-forth motion
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5
Q

What are the main characteristics of modern mammals?

A
  1. Hair
  2. Mammary and other skin glands
  3. Birth of altricial young
  4. Viviparity
  5. Enucleate RBCs
  6. 4-chambered heart
  7. Muscular diaphragm
  8. One bone in lower jaw, 3 in inner ear (reptiles have one bone in ear; multiple bones in lower jaw)
  9. Limbs rotate 90° from splayed reptilian stance (mechanically more efficient)
  10. Corpus callosum (not in monotremes or marsupials)
  11. True placenta (only in eutherians)
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6
Q

Of the two cetacean families, which have symmetrical skulls and which have asymmetrical skulls?

What is this linked to?

A
  • Mysticetes (baleen) are symmetrical
    • Linked to low-frequency hearing, bulk-straining predation
  • Odontocetes (toothed) are asymmetrical
    • Linked to high-frequency hearing, echolocation
    • Pan-bone thinning of lower jaws, fat pads, isolation of ear region
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7
Q

What is the carnassial pair?

A

P4/M1

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8
Q

In the jaw, which muscles are more deveoped in carnivores vs. herbivores?

Where does the bite force go?

A
  • Carnivores with well developed temporalis muscle with bite force going to tip of jaw (mandibular condyles line up with tooth plane)
  • Herbivores have well developed masseters with bite force going to molars (mandibular condyles above the tooth plane)
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9
Q

What are the four levels in the hierarchy of the distribution of species?

A
  • 1st order selection: Selection at physical/geographical range of a species (species range)
  • 2nd order selection: Home range of an animal
  • 3rd order selection: Use of habitat components within home range
  • 4th order selection: Procurement of foods/micro-habitat from that site (resources from habitat)
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10
Q

What are the faunal regions?

A
  • Palearctic
  • Nearctic
  • Neotropical
  • Ethiopian/Afrotropic
  • Oriental/Indomalay
  • Australian
  • Oceanic
  • Bolded have higest number of endemic families
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11
Q

What is vicariance?

A
  • Existence of closely related forms (vicariants) in different geographical areas which have been separated by formation of natural barriers
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12
Q

What is the difference between ecological dispersal and species dispersal?

A
  • Ecological dispersal: Movement of individuals or groups that leave natal to breed elsewhere (demographically important)
    • Occurs within lifetime of individual, must be successful
  • Species dispersal: Extension of a species range into a previously unoccupied area (important with vicariance) ( = range extension)
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13
Q

What are the three types of routes in dispersal?

A
  • Corridor routes: Minimal resistance
  • Filter routes: Only certain species can pass through (e.g., Beringia)
  • Sweepstakes routes: Some unusual occurrence carries an organism beyone the limits of normal ecological dispersal (rafting or wing event for bats)
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14
Q

What is Rapoport’s rule?

A

Latitudinal breadth of species tends to be larger for species at higher latitudes than for species at lower latitudes (higher latitude species are adapted to broader range of conditions)

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15
Q

What is Bergmann’s Rule?

A
  • Races from cooler climates in species of warm-blooded vertebrates tend to be larger than races of the same species living in warmer climates
  • Mass to surface area ratio will decrease with increasing size - more difficult to dissipate heat
  • Temperature almost as good as latitude for explaining size trends
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16
Q

What is Allen’s rule?

A
  • Races in warm and humid areas are more heavily pigmented than those in cool and dry areas
  • Questionable and poorly studied (could be cryptic colouration, areas could select for different colours)
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17
Q

What is the “resource rule”?

A
  • Mammals will increase or decrease body size with respect to geography or time depending on abundance, availability, and size of resources
18
Q

What are the three main layers of the epidermis?

A
  • Outer layer is the stratum corneum (dead keratinized cells)
  • Stratum granulosum - cells become keratinized
  • Stratum basale - innermost layer where cells are produced by mitosis and move upwards
  • Also have stratum lucidum between stratum corneum and stratum granulosum but only on thick skin
19
Q

What is the dermis layer of skin made up of?

A
  • Connective tissue and vascularized glands
    • Hair follicles
    • Sweat glands
    • Sebaceous glands
    • Nerve endings
20
Q

What is the hypodermis made up of?

A
  • Innermost layer
  • Consists of fatty (adipose) tissue
  • Base of hair follicles
  • Fat serves as:
    • Energy store
    • Body contouring
    • Cushion against blows
    • Insulation
21
Q

What are armadillo tiles connected by?

A
  • Non-mineralized collagen fibers called Sharpey’s fibres
22
Q

What are the three types of guard hairs?

A
  1. Spines: Stiff, enlarged guard hairs with determinate growth
  2. Bristles: Stiff, enlarged guard hairs with angora growth
  3. Awns: Definitive growth, expanded distal end, firm tips, weak base
23
Q

What are the four types of underhairs?

A
  1. Wool: Long, soft, curly (angora growth)
  2. Fur: Most common underhair, closely spaced, fine, short hair
  3. Velli: Very short, very fine hair; includes embryonic fur
  4. Lanugo: Embryonic fur shed in utero or shortly after birth
24
Q

What is the Flehmen response?

A
  • Lip curling in mammals to facilitate transfer of scent to Jacobson’s organ
25
Q

What are the four requirements for walking or running?

A
  1. Support and stability
  2. Propulsion
  3. Maneuverability
  4. Endurance
26
Q

What are the main evolutionary changes seen in horses over time?

A
27
Q

What are the differences between an ambulatory gait and a cursorial gait?

A
  • Ambulatory animals have each foot on the ground at least half of the time
  • Cursorial animals have each foot in contact with the ground less than half the time
28
Q

Symmetrical vs. asymmetrical gaits

A
  • Symmetrical: Spacing of feet is equal and makes contact with ground at even time intervals (walking, pacing, trotting)
    • More stable
  • Asymmetrical: Contact with ground at uneven intervals (galloping or bounding)
29
Q

Difference between fast twitch and slow twitch

A
  • Fast twitch: Contract quickly and powerfully but fatigue quickly (strength)
  • Slow twitch: Contract for long periods with little force (endurance)
30
Q

Difference between jumping and ricocheting

A
  • Jumping uses all four feet
  • Ricocheting involves only hind limbs
  • Collectively known as saltatorial locomotion
    • Gain efficiency in locomotion using elasticity in tendons
    • Posterior shift in centre of body mass
    • Enlarged hip muscles
    • Pelvic girdle modified to accommodate shift in body mass
    • Larger hind feet
    • Longer tail for balance
31
Q

Difference between amphibious, aquatic, and marine mammals?

A
  • Amphibious: Spend time in both terrestrial and aquatic habitats
  • Aquatic: Live most of the time in water but come on land for some activities (e.g., seals)
  • Marine: Mammals that never come onto land
32
Q

How does pectoral and pelvic oscillation differ in pinnipeds in aquatic and land environments, specifically the phocids and oteriids?

A
  • Otariids:
    • Aquatic - Pectoral oscillation - flap forelimbs, no hind limbs
    • Terrestrial - Pectoral oscillation - posture (hind facing forward) allows for weight on all four limbs
  • Phocids:
    • Aquatic - Pelvic oscillation - alternating hind limbs, forelimbs for steering; or hind limbs used in alternating force with forelimbs as rudders or paddles
    • Terrestrial - Pelvic oscillation - do not use hind limbs in terrestrial locomotion - vertical or lateral undulations called “gallumphing”; or hind limbs can be rotated forwards (like otariids) with belly supporting more of body than limbs
33
Q

What are the three ways to counteract loss of stability in marine mammals?

A
  • Pitch (for slip)
  • Roll (for surge)
  • Yaw (for heave)
34
Q

What are chevron bones?

A
  • Site for muscle attachment for downward tail motion in cetaceans
35
Q

What is Dehnel’s phenomenon?

What is Cope’s rule?

A
  • Dehnel’s phenomenon: Observation that the reduction in the body size of the common shrew in autumn is accompanied by shrinkage in the size of the skull
  • Cope’s rule: Population lineages tend to increase in body size over evolutionary time
36
Q

What is the peninsular effect?

A
  • Mammal species decline toward terminal end of peninsulas
37
Q

What is crypsis?

A
  • Colouration where mammal’s colour matches colour of substrate
38
Q

What are scent glands?

A
  • Modified hair or sweat glands that may release pheremones (chemical signals that convey information between members of the same species)
39
Q

What are the differences between claws, nails, and hooves?

A
  • Claws: Most primitive form
    • Two parts: Dorsal unguis and ventral subunguis
  • Nails: Cover only dorsal portion of phalanx
  • Hooves: Characteristic of ungulates and are derived from claws, unguis completely surrounds subunguis
40
Q

Differences between horns and antlers

A
  • Horns are only found in bovid species and have an inner core of dermal bone covered by a keratinized sheath
  • Antlers are branched ornaments made entirely of bone and are highly vascularized; shed annually
41
Q

What is the hyoid apparatus?

A
  • Located in throat region and consists of H-shaped array of small bones that support the tongue and larynx
42
Q

What are somatic muscles?

A
  • Muscles that orient the body in the external environment
    • Either striated (presence of sacromeres), skeletal (attached to bones and tendons), and voluntary (can be contracted at will)

ZOOL 408 (12 decks)

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