Lab VIII: Survey of the Mammals Flashcards
1
Q
Characteristics of the Mammalian skull
A
- Modified synapsid skull
- Jaw articulation (contact between upper and lower jaw) at dentary-squamosal joint; **dentary bone **is large in size and articulates with cranium on squamosal portion of temporal bone
- Quadrate & articular bones of other amniotes become incus & malleus bones of middle ear. With stapes, gives mammals three middle ear bones
- Two occipital condyles articulate with first cervical vertebra, the atlas
- The secondary palate separates nasal passages from oral cavity
- Tendency toward heterodont dentition (variety of tooth types), including development of double-rooted cheek teeth; most have two sets of teeth
2
Q
Characteristics of mammalian sksleton
A
- Ribs are reduced/lost on cervical and lumbar vertebrae
- Upright limb posture; legs directly below body
- Most have standard **phalangeal formula **of 2-3-3-3-3
3
Q
Characteristics of mammalian integument
A
- Presence of hair
- Integumentary glands - sweat (tubular and long); sebaceous (always associated with hair)
- Mammary glands - modified integumentary glands
4
Q
Characteristics of circulation and respiration in mammals
A
- Tidal ventilation (flow in then out) by lungs with alveoli
- Muscular diaphragm
- 4-chambered heart (complete separation of oxy and deoxy blood)
- Persistent left aorta (major - carries blood from heart to rest of body)
- Non-nucleated, biconcave RBCs
5
Q
Mammalian reproduction
A
- Internal fertilization; eggs develop in uterus with placental attachment (except monotremes - lay eggs)
- Amniotic egg
6
Q
What area of the brain is responsible for coordination, memory, and intelligence in the mammals?
A
- Neopallium
7
Q
What are the three types of integumentary glands in mammals?
A
- Sebaceous (oil) glands - open into hair follicle
- Sweat glands - not associated with hair
- Mammary glands - specialization of one of these two types
8
Q
Where do you often find epidermal scales on mammals?
A
- Epidermal scales are modifications of hardened epithelium, never are bony
- Often found on tails and feet
- Armadillos and pangolins are only mammals with epidermal scales over most of their body
9
Q
What is the formal name for the coat of mammals?
What are the three different types of hair?
A
- Pelage = coat
- Vibrissae hair - long, stiff hairs with well innervated bones. Tactile receptors on nose, legs, and around mouth and eyes = whiskers
- Guard hairs - most conspicuous, serves protective function. Can be modified (porcupine quills) or broad, flat, and overlapping
- Underhair - finely branched; mainly for insulation
10
Q
What affects molting in mammals?
A
- Hormones
- Temperature
- Photoperiod
11
Q
What are the two types of melanin pigments in mammals?
A
- Eumelanin - brown and black pigments
- Pheomelanin - red and yellow
- No pigment - white
12
Q
Characteristics of claws in mammals
Function?
A
- Composed of dorsal sac-like plate (unguis) and ventral plate (subunguis)
- Usually fixed (although retractable in cats)
- Increase traction and stability in mammals, protection, help with digging, help climb trees, hold onto prey, and kill prey (in carnivorous mammals)
13
Q
What mammals have hooves?
Function?
A
- Ungulate mammals (Atriodactyla and Perissodactyla)
- Come into direct contact with ground - good traction and prevent wear
14
Q
What are nails?
What is their function?
A
- Modified claws, cover dorsal end of digit
- Less protection than claws but allow for increased precision in object manipulation and increased tactile perception
15
Q
What mammal has spurs?
Function?
A
- Male monotremes on back of hind leg
- On platypus, spur is grooved for passage of poisonous glandular secretions
16
Q
What are the five major groups of horns and antlers?
A
-
True horns
- Family Bovidae (buffalo, sheep, goats, cattle, antelope, etc.)
- Unbranched, permanent
- Inner bony core formed from frontal bones of skull; outer layer of the horm is formed from keratinized epidermis
- Boths sexes or only male
- Each season’s growth produces ring at base of horn sheath
-
Pronghorns
- Structure similar to true horn except keratinized sheath is branched
- Keratinized sheath is shed annually
- Female pronghorns almost hornless, often lack prongs
-
Antlers
- Most male deer species; both sexes of reindeer and caribou
- Fully grown structures are entirely bony and branched, shed annually
- When antler grows, bone is covered with skin layer (“velvet”) which carries blood vessels and nerves supplying bone growth
- Velvet rubs off, revealing bony structure
- Shed after mating season, new one grows in spring
-
Giraffe “horns”
- Short, unbranched, bony processes arising from anterior region of cranium
- Covered in skin and hair
- Permanent
- Both sexes
-
Rhinoceros horn
- Only living, non-artiodactyl to possess keratinized head ornamentation
- “Horn” = solid mass of epidermal cells that are formed from a cluster of long dermal papillae (protrusions of dermis into epidermis)
17
Q
Describe mammalian teeth
What are the four different types?
A
- Two layers of hard material
- Dentine on inner, enamel on outer surface
- Mostly heterodont teeth, several functional types:
- Incisors - chisel-shaped, for nipping/slicing
- Canines - sharp and pointed, for cutting, stabbing, gripping
- Premolars - flat and ridged, for chewing and grinding
- Molars - same as premolars, posterior
18
Q
Define convergent evolution
A
- Independent evolution of similarity between species as a result of their having similar ecological roles and selective pressures
19
Q
Group?
Characteristics of group
Order?
Characteristics
A
- Group Prototheria
- Basal amniote and mammalian characteristics
- Adults lack functional characteristics
- Amniote features include egg-laying; cloaca (single duct from which both excretory and urogenital systems empty); primitive pectoral girdle
- Advanced mammalian characteristics include hair; mammary glands (lack nipples); jaw structure; endothermy
-
Order Monotremata (echidnas and duck-billed platypus)
- Only in Australia
- Echidnas have strong snout and long, sticky tongue for rooting insects and worms; long claws for diggins; body covered with spines
- Duck-billed platypus is semi-aquatic, elongated snout with leathery, moist skin; dorsoventrally flattened tail, webbed feet; eat invertebrates and fish (spurs on males –> elongations of pubis on pelvis)
20
Q
Describe the Theria
A
- Theria = subclass of mammals (Metatheria and Eutheria)
- Live-bearing; mammary glands with nipples; pectoral girdle greatly reduced; functional teeth usually present
21
Q
Group?
Characteristics?
Superorder?
Characteristics?
A
- Metatheria
- Young born in premature condition and complete development while carried by female, usually in marsupium located on abdomen
- Mammary glands open into marsupium
- Cloaca modified to allow some separation of excretory and reproductive outlets
- Superorder Marsupialia
- Very diverse, with species adapted for climbing, burrowing, grazing, and predation
- Many examples of convergent evolution with eutherians
- Only in Australia
- Zygomatic arch near top of head
- Deep jaw sulcus; 2 large holes in palate
23
Q
Order?
Characteristics?
A
- Order cingulata
- Armoured placentals
- Mostly insectivorous, some omnivorous
- Dorsal body and head covered with osteodermal armous
- Fossil forms much larger
- Formerly grouped with sloths and anteaters in clade “Xenartha”
24
Q
Order?
Characteristics?
A
- Order Pilosa
- Sloths and anteaters
- South America, mostly nocturnal
- Medium-sized placentals
- Some with enlarged claws for digging or climbing
- No incisors or canines
- Anteaters - terrestrial or arboreal; feed on termites and soft-bodied invertebrates
- Sloths - arboreal; eat leaves, buds, fruits, other vegetable matter
25
Q
Order?
Characteristics?
A
- Order Pholidota (pangolins)
- Small to medium sized
- Overlapping, keratinized scales cover most of body
- Head elongate
- Teeth absent
- Long, thin, muscular tongue
- Long claws
- Eat termites and insects
- Arboreal or fossorial
- Tropical forests and grasslands of Africa and Asia
26
Q
Order?
Characteristics?
Other mammals in order?
A
- Order Langomorpha
- Medium to large ears
- Tail short or absent
- Soles of feet haired
- Two pairs of upper incisors completely covered with enamel and grow continuously
- Diastema (gap) in place of canines
- Herbivorous, terrestrial, some burrow
- Specializations to vegetation diet include cecum for fermentation and production of two kinds of fecal pellets (one is ingested for further processing)
- Broad, “lacey” skull
- Rabbits and hares also in this order
27
Q
Order?
Characteristics?
A
- Order Rodentia
- Gnawing mammals
- One pair of incisors that grow continuously
- Diastema in place of canines
- Molars well-developed and ridged for grinding
- Adapted to most habitats
- Mostly herbivorous, some omnivorous
- Modified digestive tract for herbivory (e.g., cecum)
- Most nocturnal and active year round
- High reproductive capacity
29
Q
Order
Characteristics
A
- Order Macroscelidea (elephant shrew)
- Small African species with long, “trunk-like” noses
30
Q
Order
Characteristics
A
- Order Afrosoricida (tenrecs and golden moles)
- Insectivores of South Africa and Madagascar
- Used to be grouped with “Soricimorpha” - clade now paraphyletic
- On golden mole, can’t see eyes (on marsupials you can)
- True moles hve large hands, golden mole only has claws
31
Q
Order
Characteristics
Other mammals in order
A
- Order Eulipotyphla
- Small, primitive placentals with reduced external ears and small eyes
- 5 clawed toes
- Mostly nocturnal and burrowing
- Insectivorous, some carnivorous/omnivorous
- Shrews have a long pointed nose, rodents do not
- Solenodons, hedgehogs, moles, and shrews are in this order
32
Q
Order
Characteristics
A
- Order Scandentia (tree shrews)
- Small, squirrel-like mammals of south east Asian forests
- Pointed face, less bushy tail than squirrels, five claws in forelimbs
- Skeleton - post-orbital bar, can see entire eye
33
Q
Order
Characteristics
A
- Order Primates (includes lemurs, tarsiers, monkeys, apes, humans)
- Varying sizes
- Well developed cerebral hemispheres
- Eye sockets surrounded by bone ad directed forward = complete orbit
- 5 digits on each limb; opposable thumbs and toes
- Most omnivorous, some carnivorous/herbivorous
- More primitive species are nocturnal
- Most sp. arboreal; some with prehensile tail and/or long forelimbs for swinging, jumping
- Worldwide in tropical forests and grasslands
34
Q
Order
Characteristics
A
- Order Dermoptera
- Colugos or “flying lemurs”
- Not true lemrs, glide from tree to tree using large, furred membrane that extends from neck to manus and finally to tail
- Skeleton in lab
35
Q
Order
Characteristics
A
- Order Chiroptera
- True flying mammals
- Bones of palm greatly elongated and covered by double membrane called a patagium (skin), which is connected to the body and extends posteriorly to anke
- Some with uropatagium (further membrane behind hind feet surrounding tail)
- Most insectivorous; some tropical/semitropical eat fruit, pollen, bood, fish etc.
- Most hibernate
- Most nocturnal, hunt and navigate with echolocation
36
Q
Order
Characteristics
A
- Order Carnivora
- Small incisors, large canines
- All predatory (except pandas)
- Terrestrial carnivores with at least 4 claws on fore and hindlimbs
- All environments, some well adapted for arboreal life
- Aquatic carnivores (pinnipeds) breed on land (have limbs modified into flippers; large eyes; tail and external ears reduced/absent; typically homodont teeth; blubber for insulation)
37
Q
Family
Characteristics
A
- Family Mustelidae (weasel family)
- Marten, fisher, weasels, mink, wolverine, badger, otter, skunks
- All continents except Australia and Antarctica
- Mouth has fewer, but more specialized, teeth
- Kill prey with a bite to the neck that severs spinal cord
- Long, streamlined bodies relative to short limbs
- Long tails enhance movement, enhance balance when running and making sharp right turns
- Well-developed anal glands that produce musk and figure prominently in communication and defense
38
Q
Genus species
A
Martes americana
39
Q
Genus species
A
Mustela nivalis
Very small
40
Q
Genus species
A
Gulo gulo
41
Q
Genus species
A
Taxidea taxus
42
Q
Genus species
A
Lontra canadensis
43
Q
Genus species
A
Mephitis mephitis
44
Q
Order
Mammals in group
Characteristics
A
- Order Artiodactyla (even-toed mammals)
- Swine, hippos, camels, deer, elk, caribou, moose, giraffe, antelope, sheep, goat, bison, cattle
- Large
- Limbs end with modified 3rd and 4th digit covered with hoof
- Upper incisors reduced or absent
- Many with horns/antlers
- Most herbivorous grazers in grasslands - complex grinding teeth
- Foregut fermentation and producing cud (=ruminants)
45
Q
Order
Characteristics
A
- Order Cetacea
- Fully aquatic
- Skin overlying thick layer of blubber (no hair)
- No external ears
- Front limbs developed into flippers
- No hind limbs
- Tail modified into fluke situated in horizontal plane
47
Q
Order
Characteristics
Other mammals in order?
A
- Order Perissodactyla (odd-toed hoofed mammals)
- Horses, tapirs, rhino
- Large, bulky mammals with main axis of foot terminating on third digit with nail modified as hoof (looks like one solid hoof, as opposed to one that is split in Artiodactyla)
- All herbivorous grazers in open grasslands, with complex grinding teeth
- Rely on hindgut fermentation
48
Q
Order
Characteristics
A
- Order Tubulidentata (Aardvarks)
- Monospecific (single species) anteater-like mammal of sub-Saharan Africa with very little hair
- “Tube-like”/”peg-like” teeth
49
Q
Order
Characteristics
A
- Order Hyracoidea
- Hyraxes
- Rodent-like mammals of Africa and Middle East
- Closely related to elephants
- Whiskers all over body - sensory for mountainous regions
50
Q
Order
Characteristics
A
- Order Proboscidia
- Nose elongated into trunk
- Skin thick and leathery, nearly hairless
- Incisors modified into tusks on upper jaws
- Molariform teeth successing one another from behind
- Herbivores, graze on open grasslands
- Large, single nasal cavity
51
Q
Order
Characteristics
A
- Order Sirenia
- Manatees and dugongs
- No hindlimbs; forelimbs = flippers
- Tail modified as paddle
- Very small eyes
- No external ears
- Body hairless except for bristles around mouth
- Teeth modified and reduced
- Feed on aquatic vegetation
- Inhabit shallow rivers and estuaries in tropical and subtropical regions
