Mammalogy Flashcards
What is binomial nomenclature?
The scientific assignation of species with two parts: Genus and species. These should be italicized or underlined if written in script.
What are species?
Species are groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups and share a common gene pool
What is the hierarchy of classical classification?
Domain Kingdom Phylum Class Order Family Genus species
What are the three types of classification?
- Numerical taxonomy
- Evolutionary taxonomy
- Phylogenetic systematics (cladistics)
What is a clade?
A clade is a monophyletic group
What is a homologous character?
A character state inherited from a common ansestor
What are analogous characters?
Characteristic that has a similar function but arose independently with no common ancestry
What is convergent evolution?
Similar features arise from different ancestors as a result of similar ecological characteristics
What is another name for convergence?
Ecomorph
What is parallel evolution?
Independent modifications from the same ancestor
What is homoplasy?
Similar character state that misrepresents common descent as a result of convergence, parallelism, or reversal
What is molecular phylogeny?
The use of genetic differences in regards to the number of base pairs different to determine divergence on a molecular clock
What are synapomorphies?
Shared derived characteristics
What are symplesiomorphies?
Shared characteristics by the ingroup and outgroup that do not help in phylogenetic relationships
What are the general steps to the reptile mammal transition?
pelycosaurs to primitive therapsids to advanced therapsids (cynodonts) to mammals
What is Synapsida?
a monophyletic group that includes mammals; characters include a single temporal opening below postorbital and squamosal skull elements; dominant in early Triassic and in Cenozoic
What are Pelycosauria?
A paraphyletic group of primitive synapsids; reptile-like posture, skull, lower jaw, dentition; dominant in Permian period
What are Therapsida?
paraphyletic grade betwen pelycosaurs and mammals domiant during late Permain and early Triassic
What is Mammalia?
Established in the late Triassic, this group began in the Mesozoic era, increasing before dinosaurs went extinct, and increasing in size; still present today
What are the different eras in geological history?
Proterozoic Paleozoic -Cambrian -Ordovician -Silurian -Devonian -Carboniferous --Mississippian --Pennsylvanian -Permian Mesozoic -Triassic -Jurassic -Cretaceous Cenozoic -Paleocene -Eocene -Quaternary
What are the pulses of synapsid evolution?
Pulse 1 (Permian) - Pelycosaurs - sprawling posture, ectothermic, tropical Pulse 2 (Early to Mid Triassic) - Therapsids - increased metabolic rate, improved posture, greater jaw musculature, tropical and temperate Pulse 3 (Late Triassic) - Cynodont Therapsids - some endothermy, diaphragm, secondary palate, differentiated dentition, masseter muscle of jaw, separation of articular, quadrate, and angular bones of jaw Pulse 4 (Late Triassic to Early Cretaceous) - early true mammals - lactation, endothermic, wide geography, low diversity Pulse 5 (Cretaceous) - Therian mammals - tribosphenic molars (crush and sheer), placentals and marsupials diverge Pulse 6 (Early Paleocene to Middle Eocene) - Archaic therians and didelphoic marsupials - tropical forest type characters, first carnivores, first semi-aquatic herbivores Pulse 7 (Late Eocene to recent) - Modern therians, confined marsupials - diverse habitats, various sizes
What are the features of a tooth structure?
Crown - above gums Root - below gums Enamel - outer layer Dentin - inner layer Pulp - holds blood vessels and nerves Cementum - spongy, bone-like material hold tooth is socket Periodontal membrane Nerve and blood supply
What are the four major types of teeth implantation?
- Acrodont - attached to the surface of the bone or in a shallow depression
- Pleurodont - teeth are attached on a shelf
- Thecodont - teeth are in a socket (mammals)
- Gomphodont - multiple-rooted teeth (molars)
What is monophyodont, diphyodont and polyphyodont?
Moophyodont - one set of teeth
Diphyodont - two sets of teeth
Polyphyodont - multiple sets of teeth
What types of teeth are there?
Incisors - on premaxilla and dentary
Canines - on maxilla and dentary
Cheek teeth (premolar and molar) - post-canine, maxilla, and dentary
What is homodont and heterodont?
Homodont - similar tooth structure in mouth
Heterodont - different types of teeth in mouth
What is edentulous?
No permanent teeth
What is integument?
Glands of several types, hair follicles, fatty tissue, sensory endings, claws, hooves, nails, etc.
What are the functions of integuments?
Insulation, protection, sweating (homeostasis), reception of sensory information
What is pelage?
Whole body hair. This includes underfur (down or wool), and overfur (guard hairs).
What are the five stages of hair development?
- Follicle development - prenatal
- Anagen - hair growth, phase determines length
- Catagen - regression, cell division stops, apoptosis push up the follicle
- Telogen - rest, just below sebaceous gland, club shaped instead of bulb shaped
- Exogen - exit of hair shaft from follicle
What are hairs made of?
Three layers of keratin - a central core or medulla, layer of cortex surrounding the medulla, and an outermost layer called the cuticle
What are vibrissae?
Whiskers; specialized sensory hairs
What are the three skin glands? What are their purposes
Allow evaporative cooling and elimination of some wastes
Sebaceous glands - oily secretion for lubricating hair and skin to keep pelage dry
Scent and musk glands - social communication, marking territory, attracting mates, protection
What are mammary glands?
lobules of glandular tissue enclosed in connective tissue capsules the converge to a nipple or cistern for lactation
What are the purpose of claws, nails, and hooves?
Claws - tools and protect underlying tissues
Nails - protect the tips of terminal phalanges (toes and fingers)
Hooves - specialized claw
What are horns?
Keratinized sheaths around bony cores that do not branch except in pronghorns
What are antlers?
Bone laid down by epidermal growth layer (velvet) and typically shed annually
What are ossicones?
Similar to horns, derived from bony elements and no relation to horns or antlers (on giraffes and okapi)
What are monotremes?
remnant mammals from an early lineage; several synapsid traits including eggs, incubation, and cervical ribs; specialization
What is oviparity?
Egg-laying
What is a cloaca?
Vent for digestive wastes, kidney excretions, reproductive system products found in monotremes
What is Metatheria?
Marsupials; vacuities in palate, auditory bullae by alisphenoid bone, medially inflected angular process in dentary bone
How are metatherian teeth replaced?
Incisors and canines - vestigial, never erupt for replacement
Premolars one and two - not replaced
Premolar three - replaced by secondary teeth
Molars - secondary or permanent teeth
What is a marsupium?
Marsupial pouch not present in all marsupials
What occurs during metatherian reproduction?
Uterus is duplex, lateral vaginae on either side of canal; placenta lack villi so intrauterine gestation is short; extra-embryonic membranes include the choriovitelline (yolk-sac) placenta
How do metatherians develop?
Born with rudimentary features (lungs, forelimbs, sucking structures); long gestation
What are the differences between metatherians and eutherians?
Metatherians less diverse
Metatherians have no large social behavior
Metatherians are smaller in size
Metatherians are not as widely distributed
Metatherians have a shorter gestation period
Metatherians have precocious young
Metatherians have less endothermic ability
Metatherians have larger litter sizes
Metatherians have slower population growth
Metatherian cerebral cortexs develop more slowly
Metatherians have less behavioral plasticity
Metatherians lack highly developed antipredator behavior
What is Eutheria?
placental mammals; auditory bullae, foramina in bones of the skull that indicate changes in circulatory patterns with the brain, last incisor near canine lies in maxilla, all teeth except molars are replaced
What is the purpose of historical zoogeography?
to explain the sequence of events for the origin, dispersal, and extinction of species
What are refugia?
Pockets of suitable habitat isolated by glaciers or changes in habitat and climate
What does the movement of mammals depend on?
dispersal ability of species, tolerance of environmental conditions, and presence of barriers
How did mammals disperse?
corridors, filters, sweepstakes routes
What is a filter route?
A route that allows some species to bass but not others (i.e. the Isthmus of Panama)
What is a sweepstake route?
most restrictive route involving traversing a major barrier (i.e. the land bridge between Asia and North America)
What is the purpose of ecological zoogeography?
seeks to explain the present distribution of mammals using ecological, geological, and climate information
What is endemism?
restriction of a taxon to a specific, sometimes isolated region
What is convergence?
evolution of similar morphologies, life history patterns, and nice characteristics in distantly related organisms inhabiting the regions of similar ecological, geological and climatic conditions
What are latitudinal gradients?
increase in species diversity along a gradient from the poles toward the equator
What are causes for the decline of mammal species?
The growth of the human population, exploitation, habitat destruction, and habitat degradation
What is communication?
An action on the part of one organism that alters the behavior of another organism in a fashion adaptive to either the sender alone or both the sender and receiver
What methods of communication exist in mammals?
Odor (pheromones), sound, touch, vision
What reasons do mammals have for communicating?
Species, population, mate, or kin recognition; reproduction, agonism, social status, alarm, hunting, care, play
What is agonistic behavior?
Social fighting among conspecifics, including territorial, assertions of dominance, and mating
How do reproductive rates differ based on environment?
Animals living in harsher, less stable environments have high reproductive rates and little care while those living in stable environments offer more care and less young per time.
What is polygynous?
A mating system in which males mate with multiple females. Males are usually larger, more ornamental, and provide little care to offspring in these species
What is a society?
A group of individuals of the same species, organized in a cooperative manner that extends beyond sexual behavior. This includes alarm calling, cooperative rearing of young, formations of alliances, eusociality
What are the advantages and disadvantages of a society?
Benefit - protection from weather, predator detection and defense, group defense of resources, division of labor
Cost - increased competition, interference in reproduction, spread of disease
What is reciprocal altruism?
Cooperating with others, possibility of being paid back in the future
What is habitat selection?
A choice of the place in which to live
What is iteroparous?
Breeding multiple times throughout a lifetime
What is reproductive effort?
the energy put into current reproduction that reduces future survival and reproduction; increase with age in long-lived species; high at maturity for short-lived species
What is the difference between r-selction and k-selection?
R-selection - early maturation, large litter size, fluctuating climates
K-selection - larger body size, slower reproductive rates, stable environments
What are biological communities?
interacting populations of organisms of different species in a specific area
What is a niche?
an organism’s habitat and the role in the community
What are guilds?
groups of species exploiting a common resource base in a similar fashion
What is landscape ecology?
The study of the distribution of individuals, populations, and communities across different levels of spatial scale
Why is internal fertilization necessary in mammals?
Due to an ancestry of egg-laying, eggs produce a shell. Sperm needs to fertilize the egg prior to the shell formation
What are some forms of reproductive variations?
Delayed fertilization - hold sperm until later (seasons)
Delayed development - slows following implantation in uterine lining
Delayed implantation - suspend blastocyte development from embedding in lining (litter size of current brood)
Embryonic diapause - a period of arrested development of the blastocyst (joey in pouch prevent next until he leaves)
What is the difference between altricial or precocial?
Altrical - young that are undeveloped (marsupial)
Precocial - young that are more developed (placental)
What is endothermy?
ability to control body temperature by internal metabolic activity, physiological regulation of heat exchange, and behavioral thermoregulation
What are ways endotherms cope with the cold?
evolve large body size, have a more favorable ratio of surface are to volume, decrease rate of heat loss, increase insulation or thermoregulation, increase metabolic heat production, abandon normal body temp, or allow body temp to drop near ambient (hypothermia)
What is Bergmann’s Rule?
Animals in colder climates will be larger than those in warmer climates
What are ways endotherms cope with the heat?
sweating, panting, hyperthermia
What is echolocation?
short-range system where target are detected at close range
Is echolocation better for terrestrial or aquatic species?
Signals travel faster, further, and with less energy output in aquatic ecosystems
What is the Bruce effect?
an effect (in mice) by which the presence of a strange male or his odor causes the female to abort her pregnancy and become receptive
What is the difference between a chorioallantoic placenta and a choriovitelline placenta?
Chorioallantoic - eutherians, outer chorionic layer and inner vascularized allantois
Choriovitelline - metatherians, yolk sac placenta, no villi, weak connection to uterus
What is sexual dimorphism? Why does it occur?
One gender of a species, typically the male, is larger than the other gender. Most likely occurs due to mating rituals.
