Mammalogy Midterm

Why do we study mammals?
to gain knowledge in histology, animal science, game management, evolutionary adaptation, and ecological theory
What is the Cenozoic Era?
The age of the mammals
What is the Mesozoic Era?
The age of the reptile
Where did the Therapsid arose from?
Who dominated the Permian and early Triassic periods?
Who arosed from Cynodont ancestors during late Triassic slightly after dinasours appeared?
What is the evolutionary process of the Angular, Articular and Quadrate in the Early mammals to reptiles?
What other characteristics may have arisen in the late cynodonts?
Teeth: could chew on one side of the mouth, robust cheek teeth
Secondary Palate: lies under the roof of the mouth, shunts air from the front of the snout to the back of the mount (breathing and eating)
What are Sinocondontids and Morganucodontids?
They are the earlist known mammals, weighing around 20-30 grams.
Had premolars and molars,
3-4 times larger brain and grasping ability
What are Eutricondontids?
They are predators! Somewhat large and dentition was heterodont
Give characteristics about the order Multituberculata?
First mammalian herbivore, highly successful, and could chew on both sides of their mouth.
Monotramata are?
Eutherians are?
Placental mammals
Metatherians are?
what is a species?
groups of actually of potentially interbreeding individuals, which are reproductively isolated from other groups
Groups of individuals that share a common gene pool.
What is the Genus? and the Species when it comes to the latin name?
Genus is the group species is the individual itself.
What is the following of mammals?
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
What is it called when two closely related animals share similar modes of life and thus evolve similar structural adaptations?
what is Convergence?
When two unrelated animals share similar modes of life and thus independently evolve similar traits
What is a cladistics?
classification reflecting on the actual evolutionary history of the group
basically a simple way of ordering species into hierarchical groups.
What is a cladogram?
The order in which something evolves. phylogenetic tree
Hypothetical relatedness of groups of organisms
What is a node on the cladogram?
the last common ancestor and the point at which species separated to follow their own evolutionary pathways
How do yo produce a cladogram?
use data term characters like: DNA, proteins, morphological features
Organisms are grouped on the number of shared derived characters
what is a Synapomorphies?
Similar features within a species.
What is a Symplesiomorphies?
it is the ancestral features (like hair in mammals)
What is a sister group?
when two clades share a common ancestor
What are mammary glands?
Provides nourishment to young
estrogen and progesterone in late pregnancy stimulates growth
nursing stimulates further prolactin secretion and milk production
What are skin glands? (milk)
nursing is associated with social bonding between the mother and young.
Monotremes lack nipples.
whales, dolphins and porpoises have muscles which forces milk into their young's mouth
what are sweat glands?
Promote evaporative cooling.
eliminate some waste product
what are sebaceous glands?
moisturize (or are the reason for pimples)
what are scent/musk glands?
used for mating, marking and communication.
Where is the medulla, cortex and cuticle on the hair?
Medulla is the center of the air (the air space)
Cortex is where the pigment lives
Cuticle is the outside protective layer
What is Keratin?
made of proteins and it strengthens the hair
What is it called when mammals change their coats?
MOLT, usually matches the background environment
What is fat?
Adipose tissue
Not a unique feature to mammals, but essential to survive
what are the 3 major functions of fat?
Energy storage
Source of heat and water
thermal insulation
What are the Duplex, Bipartite, Bicornuate and Simplex uterus?
Where is the Ovary, Oviduct, Uterus, and Vagina?
Male reproductive system: general information?
Contains erectile tissue surrounded by the prepuce (sheath of skin)
in many species contains a bone -- Os penis or Baculum
Can mammals digest cellulose?
No, herbivores have a symbiotic relationship with microbes in their gut to accomplish this
What is the hindgut fermenters?
have the caecum in which fermentation (digestion) of cellulose occurs
What is the foregut fermenters?
(ruminants) have elaborate multi-chambered stomachs to accomplish
Where do mammals exist? (Places/regions)
Tundra and ice
Temperate deciduous forest
Temperate rain forest
Tropical rain forest
What are Latitudinal Species Gradient?
species/mammals richness decreases from the equator to the poles
What are North American mammal latitude Gradients?
Winter temperatures
Annual moisture
Frost-free Periods
Annual Evapotranspiration
What are the Biogeographic regions?
Nearctic Region (North American)
Neotropical Region (South American)
Ethiopian Region
Australian Region
Palearctic Region
Indo-Malayan Region
Oriental Region
Oceanic Region
What is the Palearctic Region?
Largest terrestrial region
climate is largely temperate
Isolated via Bering Strait, Himalayas and deserts
includes 36 mammalian families
no endemic families
What is the Nearctic Region?
Semi-tropical to Arctic Tundra
includes 30 families
2 endemic families
Aplodontidae (mountain beaver)
Antilocapridae (pronghorn)
What is the Neotropical Region?
tropical or subtropical climatemontagne forest and alpine tundra
was isolated for most of Cenozoic
56 families of mammals
29 endemic families
What is the Afrotropical Region?
Contains deserts, tropical savannas, tropical forest, montagne forest, alpine tundra
Greatest number of mammalian families-58
20 endemic families
What is the Indo-Malayan Region?
Includes india, Indochina, southern china, the malay peninsula, the Philippines, the islands of indoesia East of the Wallace line
tropical climate which was dominated by tropical forest
49 families
8 endemic families
What is the Australasia region?
an island region dominated by Australia but including hundreds of islands of varying degrees of isolation
very diverse climate of large tropical areas
35 families
21 endemic (all marsupial and monotremes)
What is the Oceanic Region?
Species of this region are mainly marine mammals, but bats are also native to this area
What is Antarctica?
Covered in ICE
No terrestrial mammals (but there are marine mammals
Last known mammalian fossil from the Eocene
What is the Wallace Line?
West of the Line = Asian fauna
East of the Line = Asian/Australian fauna
*(Basically through Indonesia)*
Sea level changes, continental shelves and a deep trench
What is the Great American Biotic interchange?
(re) Connection of south America into north America via the Isthmus of Panama
huge faunal interchange between the Americas
Unbalanced interchange
What is the Beringia?
At maximum Beringia was nearly 2000km wide
Mammoth Steppe climate -cold arid, short grassland with exposed ground
Fauna made up of large mammals
(basically like the land bridge)
Avenues of Faunal Interchange: 4 different interchanges
Corridors- a pathway that offers relatively little resistance to mammalian movement
Barriers- physical things that restrict movement
Filter Route- allows the passage of certain mammals but restricts others
Sweepstakes Route- large, long-distant movement by chance (occur by swimming or flying)
What defines mammalian reproduction?
Mammary glands which nourish the young
Long parental (maternal) care
relatively few young but high survival
lack of eggs or live-birth does not define mammalian reproduction
What is a Gamete?
A mature haploid germ cell that is able to unite with another of the opposite sex to form a zygote
What is a spermatogenesis?
Male sperm
What is Oogenesis?
Female ova
What is Mitosis?
Cell division that results in two identical daughter cells w/ same # of chromosomes
What is meiosis?
cell division from diploid to haploid
Rodents are what percent of all mammals?
Only anterior surfaces covered in enamel.
Rodent dental formula....
1/1, 0/0, 2/1,3/3=22
Sub-orders of Rodentia
1. Sciuromorhpa
2. Castorimorpha
3. Myomorpha
4. Anomaluromorpha
5. Hystricomorpha
Family of Aplodontiidae...
Mountain Beaver
Family of Sciuridae
tree and ground squirrels, chipmunks, marmots, prairie dogs
Families in sub-order Sciuromorpha
1. Sciuridae
2. Aplodontiidae
Families in sub-order castorimorpha...
1. Castoridae
2. Geomyidae
3. Heteromyidae
Adaptations of beavers living in the water
1. Well insulated by fine underfur and long guard hairs
2. Webbed hind feet
3. Nictitating membranes
4. Can gnaw and carry branches underwater.
How can beavers carry branches underwater?
1. Intermarial epiglottis
2. Tongue is shaped and elevated so it fits tightly against the palate
Pocket Gophers
Characteristics of pocket gophers
Highly Fossorial
Fur lined external cheek pouches
Lips close behind incisors
The two families that form a monophyletic clade within castorimorpha
Geomyidae and Heteromyidae
Kangaroo rats
Characteristics of Kangaroo Rats
1. Desert Dwellers of the new world
2. Specialized for bipedal jumping
3. External fur-lined cheek pouches
4. Ever-growing cheek teeth
5. Large auditory bullae
Families within Myomorpha...
Jerboas, jumping mice, and birch mice
Characteristics of Dipodidae
1. Very large auditory bullae
2. Cheek teeth at hypsodont
3. Elongated hindlimbs
1. Desert Species
2. Plug burrows during the day to conserve water
3. Nocturnal
4. Eat Seeds
5. Hibernate in the winter
Jumping and Birch Mice
1. Occupy boreal forest regions
2. Hibernate in the winter
3. Eat a variety of food
Characteristics of Spalacidae
1. Compact, stoutly built rodents
2. Mostly fossorial and adapted to digging
3. largely reduce ear pinnae
4. Vestigial Tail
5. Eyes small and covered
Blind mole rat
1. Smalls eyes covered in skin
2. Eat above and below ground parts of plants
3. Burrows in water saturated ground
4. Elevated heart rate
5. Maintain stable pulse
6. Density of capillaries in muscles and heart are nearly double
Family Cricetidae
1. Hamsters, new world rats and mice, voles and lemmings
2. Second largest family of mammals
3. Widely distributed
Characteristics of Hamsters (Cricetinae)
1. Palearctic distribution
2. Varied diet of plant matter
3. carry foot in internal cheek pouches
4. store food overwinter
5. Nocturnal or crepuscular
6. Hibernate over winter
Voles, lemmings, and muskrats
Regional heterothermy
Extremities are a lower temp than the core
Temporal heterothermy
Body temp fluctuates daily or seasonally
Advantages of endothermy or homothermy
1. Adapt to a large variety of environments
2. Active any time of the day
3. Maintain very high activity levels
Thermal Neutral Zone
Range of ambient temperature in which no metabolic energy is expended to regulate Tb.
Lower Critical Limit
The point which below metabolic rate must be increased
What determines the rate the rate the metabolism increases?
The insulation of the animal
Upper Critical temperature
The point above which the metabolic rate must be increase to maintain Tb
Why is it strenuous on animals when the Ta reaches the UCT?
The animal must balance evaporative cooling with water loss
Basal Metabolic Rate
Minimum metabolic rate necessary to sustain maintenance of body within the TNZ
Resting Metabolic rate
Similar to Basal but less strict
Field metabolic rate
Animals complete energy expenditure over a 24 hour period
What factors affect metabolic rate?
1. Body size
2. Ambient Temperature
3. Water
4. Food Availability
Challenges of coping with the cold
1. High MR
2. Large energy input
3. Low conductance
Ways to cope with the cold...
1. Bear it
2. Hibernate
3. Leave
Strategies of lowering energy costs when bearing cold Ta...
1. Be Big
2. Tons of insulation
3. Only heat what's necessary, when necessary
Bergmann's Rule
Populations and species of larger size are found in colder environments, and species of smaller size are found in warmer regions.
Allen's Rule
Extremities of the animals living in cold climates tend to be shorter in animals of the same species living in warmer climates.
Benefits of being larger in colder climates.
1. Conserve heat better
2. Surface area to volume ratio is lower
3. Carry more insulation
4. Carry more energy reserves
Insulation value of fur increases with __________?
Advantages of blubber
1. Does not compress underwater
2. Can dissipate heat
3. Energy storage
4. Aids in bouyancy
5. Helps in streamlining
Two ways to heat what necessary
Regional heterothermy
Countercurrent Heat exchange
A seasonal interval when an endotherm significantly decreases activity and continuously depresses metabolism and/or body temperature
Preparation of hibernation
1. Gain substantial mass in the summer
2. Begin Tb decrease and MR decrease during the summer
3. Cache food
Low Tb and Metabolic rate
Obligate Hibernator
Must hibernate
Facultative Hibernator
May or may not hibernate
Problems cause by the heat
1. Animals produce considerable amounts of metabolic heat
2. Animals absorb large amounts of heat from the environment
3. Must maintain water balance
4. Animals must eat
Solutions to problems caused by heat
1.Dissipate heat
2. Carry high heat load
3. Reduce heat production
4. Avoid hottest parts of the day
Evaporative cooling
Evaporation of of saliva of sweat from the body surface
Advantages of panting over sweating
No salt loss
Adequate ventilation
Adaptive hyperthermia
Increasing body temperature during the hot parts of the day, and then dissipating the heat in the cooler afternoon.
Ways to avoid the hottest parts of the day
1. Nocturnal behavior
2. Fossorial
3. Active above ground during cool parts of the day
Passive rewarming used to arouse from torpor and raise body temperature without the need to spend energy
Mammals are approximately _______ water by mass.
Animals experience massive physiological stress at _____________% water loss. Death occurs at ________% water loss.
10-15; 20
Water Balance
Adaptations of the camel (Must be important, it took up 6 slides)
1. Very large decrease in Tb overnight, slow passive rise in Tb during day
2. Able to withstand considerable hyperthermia
3. No Evotranspiration
4. Can concentrate its urine and reabsorb water feces very efficiently
5. Can maintain blood fluidity and its ability to disipate heat when water loss equal 20% of its body weight
What happens when water loss equals 12% body weight?
1. Blood becomes viscous
2. Heart has difficulty moving blood
3. Rate of circulation decreases
4. Can't dissipate metabolic heat
5. Rise in Tb
Dietary water
Reliance of food for water
____________ and _______________ get all necessary water from food.
Carnivores and insectivores
Metabolic Water
Water released by the metabolism of food
Urine-Concentrating Ability
Adaptions of the kidney's of desert dwelling rodents to reduce urinary water loss.
Hygroscopic layer
water absorbant layer of dried mucous and cellular debris that coats nasal passages, which dry exhaled air.
___________ causes significant water loss in females.
How do females recycle water loss?
Reingesting waste of offspring
Producing highly concentrated milk that contains little water.
Characteristics of Monotremes
1. Oldest surviving mammalian lineage
2. Cloaca
3. Oviparous
4. low reproductive rate (1 clutch/year)
5. highly specialized feeders
6. fossorial
7. Hibernation
Derived features of Monotremes
1. Bill of platypus and Beak of echidnas
2. Reduced detition
Families within the order Monotremata
Where are echidnas endemic to?
Australia and New Guinea
Characteristics of Echidnas
1. Temporarily develops pouch-like structure to incubate and protect young
2. 1-3 eggs laid directly into pouch
3. Feed on termites, ants, earthworms, and soil arthropods
4. Hibernation and/or torpor
Characteristics of Platypi
1. No pouch
2. .5-2 kg
3. Lays 2 nests in burrow
4. semiaquatic with dense pelage
5. webbed feet with clawed digits
6. feeds on plants, aquatic crustaceans, insect larvae, etc
7. Males have vemon delivered by the hindfoot
When did Therians diverge?
100 mya (mid-Cretaceous)
What are the two important strongholds of Metatherians?
Australian and Neotropic Regions
What are the Metatherians named from?
Marsupium- pouch for there young
Extinct Metatherians
1. Procoptodon goliah
2. Diprotodon
3. B. Thylacosmilus
What were the main causes of the most recent Australian extinctions?
Livestock, grazing, land clearing, introduced species
Orders of South American Metatherians
Opposums and mouse opposums
Shrew-opposum or rat opposum
Monito del monte
Australasian Metatherian orders
Three families within Dasyuromorphia
Dasyuridae- Tasmanian Devil
Myrmecobiidae- banded anteater
Thylacinidae- Tasmanian wolf (extinct)
Characteristics of Dasyuridae
Variety of Terrestrial Habitat, some arboreal
Underdeveloped Marsupium
Size range from shrew to small dog
Characteristics of Myrmecobiidae
small, long snouted animal
Long, protrusible tongue
Heavily predated by invasive red fox
Characteristics of Thylacinidae
Medium to large size dog
Stiff tail
Abdominal Pouch
Families within Peramelemorphia
Peramerlidae- Bandicoots
Thylacomyidae- 2 species of bilbies
Characteristics of Thylacomyidae
Eat invertebrates
Hide during the day
Family within Notoryctemorphia
Notorycidae- 2 species of marsupial moles
Characteristics of Notoryctidae
Inhibit sandy soils in arid NW and central AU
Mouse sized with fossorial adaptions
Vestigial eyes, ears lack pinnae, nose slits
Families within Diprotodontia
Vombatidae- Wombats
Phascolarctidae- koala
Phalangeridae- 27 species of possums and cuscuses
Macropodidae= Kangaroo, euros, wallabies
Characteristics of Vombatidae
Stocky animals, small eyes, 35 kg
Characteristics of Phascolarctidae
Highly specialized herbivore
Tufted ears, naked nose, tailless, 8-12 kg
Sedentary, feeds on Eucalyptus
Characteristics of Phalangeridae
Forests- Alpine, eucalyptus, tropical
Prehensile tail
1-6 kg
Characteristics of Macropodidae
Great size diversity
Can run up to 70 km/hr