Exam Notes 408
Popular in Mammalogy
Popular in Wildlife and Fisheries Science
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Date Created: 02/18/15
Mammalogy 11215 Mammalogy 5th edition Vaughan Ryan amp Czaplewski Exams built around lectures textbook is supplemental 0 32 counted in class quizzes 10 o In class activity 2 10 0 Species review paper groups of 5 5pgs 155pace 10 references 15 0 PA mammal first come first serve o Midterms noncumulative 30 0 Final Exam 35 Mammalogy Lab 0 What limits animals in their natural world 0 Physiology 0 Behavior 0 Ecology 11415 Mammals Where did we come from and how do we fit in 0 Why study mammals o Histology tissues and diseases 0 Animals sciences production 0 Game management maximum yield for consumption 0 Evolutionaryadaptations o Ecological theory 0 Amniota adapted to give birth on land 0 Synapsids and sauropsids I Synapsids dominated early Triassic periods 0 Survived extinction but dwindled o Evolved into therapsids o Cynodonts I Mammalia arose from cynodont slightly after dinosaurs 0 Early mammals 0 Small body and quadrupedal movement I Escape predation by being smaller I Easier access to food resources 0 Distinguishing features jaw articulation I Squamosal joined to dentary byjawjoint 0 Migration of angular articular and quadrate further into skull bone 0 Later become ear I Other characteristics may be shared with cynodonts O O O O 0 Teeth o Robust cheek teeth 0 Could chew on one side of mouth at a time 0 Secondary palate o Lies under roof of mouth 0 Shunts air from front of snout to back of mouth I BREATH WHILE YOU EAT o Hindlimb movements 0 Parasagittal plane instead of sprawling as reptiles legs under body Radiation of Early mammals Monotremata o monotremes Eurtheria o Placental mammals Metatheria o Marsupials Sinoconodonts and Morganucodontids Earliest known mammals 2030 grams Premolars and molars 34 times larger brain than comparable therapsids Grasping ability 0 Opposable hallux toe Nocturnal Mammary glands Eutriconodontids First predators 750 grams large ish Dentition was heterodont Multituberculata First mammalian herbivore Highly successful Could chew on both sides oftheir mouth Ptiodus showed arboreal specialization Others were semifossorial First mammal with diastema gap between teeth no canines 0 End of Mesozoic Earth begins to split to form independent land forms 0 Allows for barriers for mammals which allows for niches Independent adaptations and evolution 0 Classification binomial nomenclature 0 Species groups of actually of potentially interbreeding individuals which are reproductively isolated from other groupsgroups that share a same gene pool Kingdom phylum class order family genus species Parallelism occurs when two closely related animals share similar modes of life and thus evolve similar structural adaptations Homologous traits 0 Convergence when two unrelated animals share similar modes of life and thus independently evolve similar traits I Analogous traits o Phylogeny reconstruction 0 Based on similarity among organisms o Cladistics classification reflecting the actual evolutionary history of a group I Cladogram hypothetical relationships I Organisms are grouped on the number of shared derived characteristics 0 Synapomorphies o Symplesiomorphies are ancestral features ie hair in mammals I Monophyletic groups of organisms that share a single node I Sister groups most closely related 11615 Mammal Characteristics 0 Skin glands o Mammary glands I Provide nourishment to young I Estrogen and progesterone in late pregnancy stimulate growth of glands I Prolactin and growth hormone stimulates milk production 0 Nursing stimulates more production I Nursing associated with social bonding I Monotremes lack nipples I Water mammals have muscles which force milk into young s mouth 0 Sweat glands I Promote evaporative cooling I Eliminates some waste products 0 Sebaceous glands I Moisturize o Scentmusk glands I Used for mating marking and communication 0 Hair No analogous feature Coat is called PELAGE I Medulla cortex cuticle dead cell layers in hair 0 Keratin I Made of proteins I Strengthens hair 0 Mammals change coats MOLT I Coat color usually matches background environment I Most have countershading 0 Back and sides are dark but underside venter is lighter I Some have warning coloring o Aposematic coloring ie skunk fur 0 Fat adipose tissue 0 Not unique to mammals but essential to survival 0 Three major functions Energy storage Source of heat AND water Thermal insulation 0 Circulatory System 0 4 chambered heart not unique to mammals Left atrium more muscular Sinoatrial node sends electrical pulse to atrioventricular node which sends electrical pulse to stimulate contractions Valves stop blood from flowing backwards 0 Red blood cells RBCs are biconcave disks and do not have nuclei except Camels No nuclei and disk shape allows for more oxygen to be carried Unique to mammals 0 Respiratory System 0 Trachea bronchus bronchi bronchioles alveoli o Lungs fill entire thoracic cavity Framed underneath by stomach diaphragm Surrounded by pleural fluid 0 Level of C02 in blood stimulates breathing not lack of 02 0 Reproductive System 0 Females o Males o Digestive System Both ovaries are functional Embryo fertilized in uterine tubes fallopian Embryo develops in uterus Nourished by maternal blood stream via placenta Three types of systems 0 Bipartite branched o Duplex branched o Simplex human system Penis 0 Contains erectile tissue surrounded by prepuce sheath of skin o In many species contains a bone Os Penis or Baculum Testes lay outside the body in the scrotum except cetaceans 0 Body temperature too high 0 No mammal has the ability to digest cellulose Herbivores have symbiotic relationship with microbes in their gut that breaks down cellulose Hindgut fermenters have caecum which can ferment digest cellulose 0 Located behind the stomach I Foregut fermenters ruminants have elaborate multichambered stomachs to accomplish o The brain 0 Very large in comparison to any other organism of similar size 0 Neopallium I Most characteristic brain aspect of higher mammals o A mantle of grey matter that overlays the surface of the more primitive vertebrate brain 0 Split in two halves connected communication by a large concentration of nerve fibers 0 Corpus callosum 0 Sense organs 0 Smell I Very acute in mammals 0 May be due to nocturnal origins I Largest gene family in mammalian genome I Jacobson s organ vomeronasal detects pheromones o Puberty female estrous cycle mate choice territory defense kin recognition social resolution etc 0 Hearing I Only vertebrate to have pinna o Directs sound into ears I Auditory canal tympanic membrane activates middle ear malleus incus stapes inner ear semicircular canals cochlea o Malleus hammer o ncus anvil o Stapes stirrup 0 Vision I Tapetum lucidum reflective structure improves night vision I Eye color due to melanin pigmentation in the iris I Retina consists of rods and cones 0 Touch I Vibrissae whiskers o Tactile organs on face head and lower limbs o Controlled by a complex of muscles 12115 Mammal Characteristics Cont d 0 Skeleton o More simplifiedossified 0 Bone growth I Epiphysis where the articular surface occurs 0 Articular cartilage o Spongy bone I Diaphysis the shaft of the bone 0 Medullary cavity 0 Nutrient foramen I Epiphyseal zone or metaphysis cartilaginous zone of growth 0 Skull I Process projection or outgrowth used for muscle attachment I Condyle prominence at the end of a bone roundmost often forming a joint I Foramen opening hole lets blood vessels and nerves pass through I Fossa a depression where muscles sit I Symphysis fibrocartilaginous fusion between two bones I Joint articulation between two bones o KNOW BONE CHART IN LECTURE EACH BONE IS FAIR GAME 0 Teeth I Mammalian dentition is heterodont consist of teeth that are different in form and function 0 Incisors o Canines o Premolars o Molars I Teeth occur on the premaxillary maxillary and dentary bones ONLY I 2 sets of teeth 0 Deciduous baby 0 Permanent I May be brachydont short crown hypsodont high crown or hypselodont continuous growth I Patterns cusp of molars o Dilambdodont cusps comprised of quotVquot or quotWquot shapes 0 Bats shrews moles o Bunodont 34 rounded cusps o Pigs bears raccoons humans 0 Lophodont elongated transverse cusps o rodents o Selenodont cusps elongated anterioposteriorly o Ungulates o Sectorial shearing or cutting bladelike carnassials o Carnivores I Dentition patters or formula number of teeth of a particular kind on ONE side of the upper jaw over the corresponding number on the lower jaw o Humans 22 11 22 22 0 Wolves 33 11 44 23 I Diastema space between incisors and molars lacking canines Zoogeography of Mammals 0 Patterns of distribution 0 Latitudinal species gradient I Species mammal richness decreases from the equator to the poles 0 Higher primary productivity 0 More land area 0 North American mammal latitude gradients I Winter temperature I Annual moisture I Frostfree periods I Annual evapotranspiration I Elevation 0 Latitudinal hypothesis OPPOSITE for marine mammals I Food distribution 0 Biogeographical regions SELF LEARNING SLIDES GO OVER LATER o The Wallace Line 0 West of the line Asian fauna 0 East of the line AsianAustralian fauna o The difference I Sea level changes I Continental shelves Sunda and Sahul I Deep trench between Sunda and Sahul shelves 0 The Great American Biotic Interchange 0 Connection of South America into North America via the STHMUS OF PANAMA 0 Huge fauna interchange between the Americas I SA fauna were autochthonous began there and endemic only found there prior to interchange o Unbalanced interchange I South American taxa generally did little diversification and impact in NA I North American taxa radiated explosively in SA 0 Beringia land bridge connecting SiberiaRussia to Canada and NA 0 At maximum nearly 2000km wide 0 Mammoth steppe climate cold arid short grassland with exposed ground Heavy COLD winds 0 Fauna made up of large mammals o How humans migrated to NA 0 Speciation by Vicariance speciation due to geographical separation o Avenues of faunal interchange o Corridors a pathway that offer relatively little resistance to mammal movement 0 Barriers physical things that restrict movement 0 Filter route allows the passage of certain mammals but restrict others 0 Sweepstakes route large long distant movement by chance I Must occur by swimming or flying rafting I Probability is extremely low and decreases as the distance of the route increases 12315 0 What defines Mammalian reproduction o Mammary glands which nourish the young 0 LONG parental maternal care 0 Relatively few young but high survival rate 0 Lack of eggs or live birth DOES NOT define mammalian reproduction o Sperm maturation o Spermatogenesis I Germinal cell diploid 9 primary spermatocyte Meiosis 1 Secondary spermatocytes haploid Meiosis 2 Spermatids haploid 9 Spermatozoa 0 Egg maturation o Oogenesis I Oogonia mitosis mitosis egg 0 Primordial follicles containing primary oocytes o FSH LH Secretion at sexual maturity 0 Early primary follicle 0 Primary follicle 0 Secondary follicle 0 First meiotic division completed 0 Graafian follicle containing secondary oocyte 0 Second meiotic division starts 0 Ovulation 0 Corpus luteum 0 Corpus albicans o If no fertilization o Fertilization o Ovum 9 fertilization 9 fusion of egg and sperm pronuclei 9 zygote 9 cleavage 2 cell 4 cell 8 cell 9 Morula 9 Blastocyst 9 implanted blastocyst 0 Everything happens in the fallopian tubes until the Morula o Therian Reproduction o Metatherian reproduction is associated with I Long lactation period relatively short gestation I Virtually embryonic offspring o Eutherian reproduction is associated with I A long gestation I Anatomically complete relatively precocial offspring o Estrous Cycle Hormone levels in the blood 0 FSH spike in proestrous o Follicle phase 0 Developing follicle o Estrogen and LH spike in estrous o Ovulation o Progesterone spike just after metestrous o Luteal phase 0 Corpus luteum formation 0 FSH spike in Diestrous o Menstruation Monestrous mammals females become estrus reproductively receptive for only short periods of the year and are anestrus for the remainder Spontaneous ovulation ovulation without copulation occurs in many mammals Induced ovulation occurs in some mammals o Ovulation occurs only after copulation o In some mammals can occur after tactile or pheromone stimulation 0 Embryonic development in metatherians Fertilized egg gets coated in mucoid layer Upon entering uterus egg gets keratin shell membrane Remains in 39shell for nearly 75 of gestation Only days until parturition does a choriovitelline placenta Degree to which freed blastocyst invades the endometrium varies 0 Embryonic development in eutherians o Placenta Blastocyst enters uterus zona pellucida ruptures Allows for o Nutrients diffusion o Respiration o Excretion Acts as a barrier preventing many things from entering the fetal blood stream 0 Including hormone regulation 0 Parturition metatherians Corpus luteum o Releases progesterone and relaxin o Softens cervix and vaginal canal Fetal pituitary gland releases AdrenoCortical Releasing Hormone ACTH o Increases cortisol levels in mother and fetus o In fetus stimulates prostaglandin release and uterine contractions o In mothers stimulates uterine contractions and a pulse of prolactin I Stimulates milk production and decreasesstops progesterone secretions from corpus luteum Born still embryonic o Precocial forelimbs and head O O o Particularly mouth and tongue 0 Epiglottis allows suckling without need of interruption for breathing o Welldeveloped sense of touch and smell 0 Rudimentary lungs 0 Gas exchange primarily via the skin 0 Hindlimbs do not exist 0 Poorly developed intestines and colon Parturition in eutherians The placenta produces Corticotrophin Releasing Hormone CRH into maternal and fetal blood stream 0 Causes release of ACTH and subsequent release of Cortisol and Estrogen o Uterine contractions 0 Increase sensitivity of uterus to oxytocin 0 Increase prostaglandin release 0 Softening of cervix 0 Positive feedback of contractions on Prostaglandin and Oxytocin production At birth young are born comparatively precocial o Placenta is also birthed o Nondeciduous none ofthe maternal endometrium is lost and no bleeding occurs 0 Deciduous placenta torn away from mother at birth and bleeding occurs 0 Loss of placenta removes major source of progesterone inhibits prolactin Lactation 0 defining characteristics of being a mammal o Mammogenesis preparation of mammary glands 0 Under control of progesterone Lactogenesis milk production 0 Stimulated by prolactin produced when suckling occurs 0 Inhibited by progesterone Release of milk milk letdown o Caused by oxytocin produced when suckling occurs 0 How to meet energy requirements 0 Increase food intake 0 Decrease activity 0 Change diet 0 Anatomical changes for increased absorption Lactation in metatherians LONG LONG time Early lactation 0 Where young are permanently attached to the teat 0 Milk is very dilute and contains mostly sugar Late lactation 0 Young not permanently attached 0 Milk is high in fats proteins and complex sugars 0 Energy and Breeding Strategies I Capital breeders 0 Those that provision young based on energy accumulated at an earlier time o Eg harbor seal accumulates fat to support annual lactation highly predictable breeding season I Income breeders 0 Those that provision young based on energy concurrently gained 0 White footed mouse adjusts reproduction to environmental conditions I Highly unpredictable breeding all year 12615 Reproduction II o Monotreme reproduction o Ancestral traits I Oviparous lay eggs I Fetal egg tooth allows offspring to break out of egg I Incubation outside of body I Lack of teats 0 Still nourish their young with milk I Have mammary tissue 0 Embryonic development I In the fallopian tube the zygote is o Coated with mucoid layer 0 Layer of ovokeratin added 0 Forms thin shell membrane I In the uterus 0 Second membrane added 0 Uterine secretions provide nutrients I Very close to laying 0 Third more porous layer added I At laying 0 Eggs covered in sticky coating 0 Laid into pouch where incubation occurs I After hatching shortly after laying 0 Young finds mammary lobule begins nursing 0 Found inside the pouch 0 Very undeveloped 0 Can continue to nurse after leaving pouch 0 Timing of reproduction I Favorable environmental conditions Photoperiod daylength 0 Very good cue in PREDICTABLE environments 0 Interpreted by pineal gland I When day is short pineal secretes melatonin o Depresses gonadal activity Temperature 0 AMBIENT temperature has little effect 0 Plays role in controlling food supply plants Energy Nutrition I Food availability Number one cause of timing in reproduction I Alternative strategies Life history strategies Delayed fertilization o Sperm storage in females 0 Adaptive in animals with long dormancy periods and short active seasons 0 Allows gestation to being immediately at end of dormancy Delayed implantation o Ovulation fertilization and initial cleavage into blastocyst occur but further development paused I Blastocyst floats freely in uterus I In mammals in which postpartum copulation may occur but female needs to nurse current young Delayed development 0 Blastocyst implants into uterine lining at which point embryonic development is arrested I Allows mating to occur but delays parturition until food availability is greatest I May be important in nursery colonies so that parturition is synchronous o R mice or rodents fast reproduction I Short maturation time I Short lifespan I Highjuvenile mortality I Large litter size I Early first breeding I Small offspring I Low parental care 0 K elephants or humans slow reproduction I Long maturation time I Long lifespan I Lowjuvenile mortality I Small litter size I Late first breeding I Large offspring I High parental care 0 Semelparous I One reproductive event with many offspring o teroparous I Many reproductive events with few offspring o Dasyurids family of marsupials I Highly radiated o Habitats include forests grasslands alpine arboreal and semi aquatic I Gestation length of 1216 days and lactation length from 39 months 0 Genera Antechinus I Semelparous I Females are monestrous o Synchronous mating even among species occurs during a 23 week window 0 Cued to photoperiod I Females often die after weaning I All males die after breeding o Intense mating competition 0 Complete loss of body reserves do not eat during 23 breeding period 0 Will mate continuously for 12 hours 0 Massive spike in cortisol levels results in ulcerations anemia parasitic infestations o Altricial young I Pink eyes closed I Relatively underdeveloped I No thermoregulation I Incapable of moving on their own 0 Precocial young I Covered in fur eyes open I Large brain well developed I Capable of moving on own 0 Infanticide and termination of pregnancy I Maleinduced termination o Mediated by social olfactory and endocrine changes in the female 0 BRUCE EFFECT males don t actually kill offspring I Infanticide 0 Killing of nonrelated offspring by males I Both result in new males taking over an area or harem I Result in early return to estrus by females 0 Increases new male fitness 13015 Snowshoe hares and the stress of the 10year cycle 0 Stress response 0 HPA hypothalamic pituitary adrenal cortex 0 Hippocampus releases CRH mRNA or AVP mRNA through Hypothalamic PVN I Anterior pituitary releases ACTH 0 Causes adrenals to produce Glucocorticoids o NEGATIVE FEEDBACK MECHANISM I Pathway gets shut off throughout the day I Stressor can turn on pathway 0 When stressor goes away pathway shuts off and levels go back to normal again 0 Glucocorticoid increase I Increase energy mobilization I Suppression of growth I Suppression of immune system I Suppression of reproduction 0 Chronic stressors I Cause many problems over time o Prenatal programming I Effects derive from environmentally induced alterations of maternofetal signaling involving systems that determine fetal GC exposure 0 If mom is stressed baby also gets those hormones and effects 0 Postnatal programming I Permanent change in brain after birth 0 Effects derive from environmentally induced alterations of maternoneonatal interactions involving systems that determine methylation patters of GR gene promotor sequences 0 Results in less receptors for stressors in brain 0 Negative feedback loop weaker 0 Higher GC in body 0 Higher stress individual 0 Maternal stress effects I Those mechanisms which act as translators between the maternal environment and phenotypic responses in offspring I The effects a mother s phenotype has on her offspring s phenotype that cannot be solely ascribed to inherited genetics 0 Snowshoe hare populations 0 Low phase population remains low for up to 5 years after crash even though there are less predators and ample food resources available 0 In the incline phase average of 4 litters per year 0 In decline average of 2 litters per year Order Lagomorpha Sister clade Rodentia o Leporidae 0 000 0 Skull I Supraorbital process I Parietals fenestrated I Postorbital process I Fenestrated rostrum maxillae I Tiny second incisor 12 genus and 62 species 300g pygmy rabbit up to 7kg arctic hare Primarily nocturnal or crepuscuar I Active at nighttwilight Coprophagous reingest soft fecal pellets I Hind gut fermenters Dentition pattern 21 00 32 33 28 Testes become scrotal during the breeding season Rabbits Altricial young Hares precocial young 0 Ochotonidae Pikas O 0 Skull I No supraorbital process I Maxilla with fenestra I Short rostrum I Parietal lacks fenestration I 2nd incisors peg like 1 genus Ochotona and 30 species 100150g mouse sized Gather LARGE hay piles I Used to survive winter In NA they inhabit talus slopes in boreal or alpine areas Males lack scrotum I Testicles descend eventually Dentition pattern 21 00 32 23 26 o Lagomorphs O O 0 Like originated in Asia 13 genera amp 92 species Highly fenestrated skull I Holes in skull 121 dentition pattern I Peg like incisor behind front incisor Large diastema and lack of canines Teeth are hypsodont and lack root I High crown 2215 0 Have unique joint in skull that allows slight movement I Because of saltatorial movement 0 Jumping and hopping 0 Active all year 0 Snowshoe hare o Lagomorpha Leporidae Lepus Lepus americanas 0 White fur in winter and brown fur in summer 0 Biology I Weigh 12001800g relatively small I Home ranges of 510ha I In summer they eat 0 Forbs o Grasses 0 Leaves I In winter they eat 0 Twigs o Bark I Live completely above ground and are crepuscular I Synchronous breeding o All females give birth within 7 days of each other approx May 23rd I Two to four litters per summer with 36 leverets per litter I Gestation of 3537 days and weaning 2428 days I Hares are born precocious I 95 of adult hares die due to predation o 81 leverets die 0 Population cycles I Low phase driven by maternal stress created during decline and maintained during low phase 0 Babies inherit stress from mothers I Rest of cycle heavily influenced by direct predation 2415 Thermoregulation o Endothermy and homeothermy o Mammals are endothermic within heat and homeothermic same heat 0 Very costly and cost increases as temperature decreases 0 Regional heterothermy I Extremities are held at lower temperature than the core I Lowers energy costs 0 Temporal heterothermy I When torpor fluctuates daily or seasonally 0 Advantages I Ability to adapt to large variety of environments I Can be active at any time of day I Maintain very high activity levels Tb Ta 0 O O 0 Ta ambient temperature Tb temperature of the body C conductance V02 oxygen consumption Thermal neutral zone range of ambient temperature in which no metabolic energy is expended to regulate Tb OOOO Postu ring Fluffing or compressing fur Localizing vascular shiftsflow Daily activity Digestion Conductance amount of heat lost to environment 0 0 Can minimize by I Living in warmer environments minimize diff between Tb and Ta I Having more insulation I BERGMANN farther from equator bigger species and ALLEN s Rule extremities longer closer to equator BUT minimizing heat loss may not always be the concern desert animals Critical limits of TNZ O O LCT the point which below metabolic rate must be increased to maintain constant Tb UCT point above which metabolic rate must be increased to maintain Tb Metabolic Rate 0 O V02 CTbTa Basal metabolic rate minimum metabolic rate necessary to sustain maintenance of body within TNZ I At rest but not sleeping I NO digestion I Not reproductive Resting metabolic rate similar to BMR but less strict I At rest difficult to have an animal at perfect rest I Post digestion difficult to have 0 digestion I No reproduction Field metabolic rate animals complete energy expenditure over a 24 hour period I Animal is active and not active I Is resting and not I Is eating foraging running from predators etc Factors affecting MR I Body size mice has higher MR than elephant I Environment 0 Temperature 0 Water 0 Food availability 0 Adaptations to coping with cold 0 In the cold animals face the big challenge of having a large difference between TbTa Must have a high MR 0 Need lots of energy input Food Must have low conductance 0 Strategies to coping with cold Bear it o Involves a combo of O O O Maintaining Tb Extremely high MR Low thermal conductance 0 Strategies to lower cost 0 Hibernate Be big I Large animals conserve heat better I Surface area to volume ratio lower 0 Heat production is roughly proportional to volume 0 Heat loss roughly proportional to surface area I Carry more insulation I Larger animals can carry more energy reserves fat Have tons of insulation I Insulative value of fur increases with thickness I Blubber 0 Does not compress under water 0 Alternative advantages 0 Can dissipate heat 0 Energy storage 0 Aids in buoyancy o Helps in streamlining Only heat what s necessary when it s necessary I Regional heterothermy I Countercurrent heat exchange When necessary behavioral adaptations I Active when it is warmest part of the day I Huddling 0 Alone or in groups 0 The drop in Tb associated with hibernation is NOT hypothermia O O Hypo unregulated loss of body temperature Hibernation REGULATED loss of body temp o How to prepare 0 O O Hibernators gain substantial mass during summer Begin Tb decrease and MR decrease during summer Gather cache 0 During hibernation animal employ 1 of 2 strategies 0 Eat or not eat 0 Why only eat at end of hibernation 0 Terms Torpor low TB body temp low MR Heterothermy change in body temp regulated Euthermy high normal body temp Obligate hibernator must hibernate AGS Facultative hibernator oftencan hibernate don t need to OOOO chipmunk I Leave 0 Many bats particularly tree roosting bats migrate south 0 These animals also use daily torpor 2915 Thermoregulation 2 dealing with heat 0 Problems with the heat 0 Animals produce considerable amount of metabolic heat 0 Animals can absorb considerable heat from environment 0 Animals must maintain water balance 0 Animals must eat 0 Solutions to the problem 0 Dissipate heat as much as possible I Morphological adaptations o Bergman s and Allen s rules 0 Many animals have reduced fur or naked surfaces 0 Vasodilation I Evaporative cooling 0 Evaporation of liquid saliva or sweat from body surface 0 Panting 0 Used entirely for heat dissipation and temperature regulation 0 No salt loss 0 Always adequate ventilation o Takes energy and effort to pant 0 Carry a higher heat load I Adaptive hyperthermia 0 Increasing passively body temperature during the hot parts of the day 0 Higher setpoint for evaporative cooling 0 Passive heat dissipation during cooler evening 0 Large variation in core body temp to serve as heat storage 0 Body temp varies in phase with ambient temp 0 Body temp should increase with increasing heat stress O O O 0 Body temp increases should be linked to prevent water loss Reduce heat production I Behavior adaptations o Cheetahs and gazelles can only run for a short period of time before they must stop to prevent overheating o Jackrabbits use sneaking escape behavior to reduce heat production I Regulate body tissues at different set points 0 This allows certain body parts to be warmer and others cooler 0 Animals may allow their body temperature to increase to higher set points because they can keep others cool PARTICULARLY THE BRAIN o Countercurrent cooling system I Carotid rete system Thompson s Gazelle Avoid heat and hottest times of the day I Strict nocturnal behavior I Fossorial behavior I Active above ground only during the coolest part of the day Other strategies I Desert rodents can enter torpor at hottest times of the day 0 Reduced energy needs 0 Reduced metabolic rate I Bask passive rewarming used to arouse from torpor and raise body temp without need to spend energy 0 Water regulation 0 O Mammals are approximately 23rds water by mass Massive physiological stress at 1015 loss I Death at 20 loss in many mammals MUST MAINTAIN WATER BALANCE intake output Avoidance I Minimize water loss 0 Remain inactive during the day 0 Forage at night or when cooler Periodic drinkers I Special adaptation of camels 0 Can go 17 days in winter and 7 days in summer without drinking I Very large decrease in body temp overnight slow passive rise in body temp during day I Can concentrate urine and reabsorb water from feces very efficiently I Water concentration in blood remains constant at 20 loss by mass 0 Water lost from other areas Water loss equal to 12 body weight I Blood becomes thick viscous I Heart has difficultly moving blood I Rate of circulation decreases I Reduction in ability to dissipate metabolic heat I Sudden increase in body temp I Death 0 Dietary moisture I Reliance on food for water 0 Succulent plants can provide lots of water 0 Adaptations to deal with high oxalic acid and salt 0 Kidneys able to produce highly concentrated in urine 0 Urineconcentrating ability adaptations of the kidney to reduce urinary water loss I Again adaptation found mainly in desert dwelling rodents ofthe heteromyidae dipodidae muridae I Ex kangaroo rat 0 5x more concentrated than humans 0 Twice as concentrated as sea water 0 Nasal countercurrent heat and water exchange I For kangaroo rat 0 Tb 38C 0 25 relative humidity 0 At 30C Ta can recover 54 of moisture used to humidify inhaled air 0 At 15C can recover 88 I Hygroscopic layer water absorbent layer of dried mucous and cellular debris that coats nasal passages which dried exhaled air FOUND IN CAMELS 0 Lactation I Special time limited case of significant water loss in females 0 Water requirements can increase by 100 during lactation o Recycle lactational water lost by reingesting urine and feces of offspring 0 Milk in desert dwelling species may be highly concentrated with little water content 21115 Order Rodentia o 42 of all mammals o 33 families 0 481 genera o 2277 species 0 Cosmopolitan distribution 0 Characteristics 0 5 50kg o Hypselodont incisors I Only anterior surfaces covered with enamel 0 Causes beveled tip 0 Dental formula 11 00 21 33 22 0 They gnaw and grind I Requires disengagement of incisors or cheek teeth while the alternative is occluded Division of labor I Glenoid fossa of squamosal is elongated anteriorposteriorly o Suborders o Sciuromorpha Allows for fore and aft movement of mandible and transverse movement I Family Aplodontiidae Mountain beaver o Castorimorpha Single species Aplodontia rufa Only rodent in which the masseters are completely zygomatic in origin I Family Sciuridae tree and ground squirrels chipmunks marmots prairie dogs 51 genera 278 species Skull arched in profile Front zygomatic arch is flattened where lateral masseter rests against it o Sciuromorphous condition Generally diurnal herbivore but will eat wide variety of items Dental formula 11 00 121 33 2022 Variety of strategies for surviving winter 0 Remain active but sheltered red squirrel o Hibernate chipmunks Variety of habitats and locomotion flying squirrel vs red squirrel I Family Castoridae Beavers 2 species Over 30kg Dental formula 11 00 11 33 20 Semiaquatic 0 Special adaptations to living in water Well insulated by fine underfur and long guard hairs Large webbed hind feet Small eyes with nictitating membranes Nostrils and ears have valves that can be closed during submersion They can gnaw and carry branches with their mouth open under water 0 Epiglottis is internarial o Tongue shaped and elevated such that it fits tightly against the palate so water cannot pass into the pharynx Ecological engineers Active all winter 0 Only eat wood and some green plants during summer I Family Geomyidae pocket gophers Highly fossorial ground dwelling 6 genera 40 species Fur lined external cheek pouches o Lips close behind incisors Dentition 11 00 11 33 20 I Family Heteromyidae o Myopmorpha Strongly adapted to desert life of NEW WORLD 6 genera 60 species External furlined cheek pouches Specialized for bipedal jumping Large auditory bullae Dental formula 11 00 11 33 20 o EVER GROWING CHEEK TEETH I Family Dipodidae jerboa jumping mice birch mice Very large auditory bullae Dental formula 11 00 010 33 1618 Cheek teeth are hypsodont Hindlimbs elongated JERBOA 0 Desert species similar to Heteromyidae I Plug burrows during the day to conserve water I Nocturnal I Eat seeds 0 Hibernate in winter in deep burrows Jumping mice and birch mice 0 Occupy boreal forest regions 0 Hibernate in winter in deep burrows 0 Eat a variety of food seeds and plants insect larvae etc I Family Platacnthomyidae tree mice I Family Spalacidae fossorial rodents Compact stoutly build rodents with short muscular limbs 0 Mostly fossorial and adapted to digging Dental formula 11 00 00 33 16 Ear pinnae largely reduced Tail vestigial Eyes small and covered in fur or skin BLIND MOLE RAT Spaax spp 0 Small eyes covered in skin I Degenerate optic nerve Eat above ground and below parts of plants Burrow in water saturated ground I Anoxic conditions 0 Special adaptations to have elevated heart rate and maintain stable pulse at low oxygen I Density of capillaries in muscles and heart are nearly double I Family Calomyscidae I Family Nesomyidae I Family Cricetidae Neotominae New world woodrats deer mice harvest mice 0 Second larges family of all mammals o 130 genera 681 species I Includes hamsters new world rats and mice voles and lemmings o Widely distributed from 7 degrees south of north pole to 12 north of south pole o SUBFAMILIES o Cricetinae hamsters I Palearctic distribution old world I Varied diet of grains leaves roots etc 0 Carry food in INTERNAL cheek pouches 0 Store food over winter I Nocturnal or crepuscular I Hibernate over winter but not always torpid o Arvicolinae voles lemmings muskrats I Collared lemming lives on the north coast of Ellesmere island 0 Only rodent to turn completely white in winter 0 Sigmodontinae I Vast majority live in south America 0 Adaptations in kidneys to produce highly concentrated urine 0 Eats halophytic plants 0 Lives in high Andes deserts I Family Muridae largest family of rodents o Largest family of mammals o 32 of living rodents o 150 genera and 730 species 0 SUBFAMILIES Deomyinae Gerbillinae Leimacomyinae OOO Murinae Mice and rats I Largest subfamily with 561 species I Naked scaly tale in most I Extremely widespread and can be terrestrial semifossorial arboreal aquatic etc I Heavily associated with humans known for high outbreaks o Otomyinae o Anomaluromorpha scalytailed squirrels I 3 genera and 7 species I Nocturnal I Resembled flying squirrel 0 Tail is tufted and has area with two rows of scales 0 Aids with climbing and clinging to trees I Diet of sap leaves and insects O I Occupy tree cavities I Family Pedetidae Hystricomorpha Only 2 species form single genus Inhabit sandy soils in semiarid areas of east and southern Africa About the size of a rabbit o Bipedal movement 0 Elaborate burrows 0 Large eyes and ears I Predator detection I Have tragus that shuts to protect ears 0 Only have one young I Family Diatomyidae Discovered in 2004 on a kebab skewer Example of the Lazarus Effects think something is extinct but then rediscover o In this case gap of approximately 11 million years I INFRAORDER HYSTRICOGNATHI Family Bathyergidae African mole rat 0 6 genera and 17 species 0 Lack ears or greatly reduced pinnae o Lips closed behind incisors o Heterocephaus gaber naked mole rat I Eusocial mammals like bees 0 Have queen breeder males and sterile female workers I May be resistant to cancer I Long lived up to 31 years Family Hystricidae old world porcupines o 3 genera and 11 species 0 Very similar to new world porcupines 0 Different in that they are mainly terrestrial and NOT arboreal 0 Dig extensive burrows Family Erethizontidae new world porcupines o Quills conspicuously marked with dark and light bands I Are barbed at the tip I Can progress into the flesh 1mmhr o Are partially arboreal 0 Eat cambium throughout the winter 0 Very docile Family Dinomyidae Pacaranas 0 Very rare and found in the foothills of the Andes I Endangered rodent o Extinct relative was largest known rodent gt1000kg Family Caviidae o Herbivorous o Widespread through SA and Chile Order Erinaceomorpha o Dolichotinae Long slender legs Cursorial movement run like a horse 0 Foot posture is digitigrade Evergrowing cheek teeth Diurnal Form loosely associated groups Mate for life 0 Hydrochoerinae Capybara Largest living rodent Semiaquatic life like minihippos Webbed toes 0 Eye and nostril at top of head 0 Scent gland at top of nose 0 Swim and dive very well Highly cursorial and can reach very fast speeds Form large family groups with single dominant male Family Dasyproctidae 0 Medium sized rodent 2kg 0 Inhabit tropical forests and are diurnal o Agile and fast runner o Courtship behavior scatterhoarders Male sprays female with urine Female goes into frenzy dance Allows male to copulate 0 Family Erinaceidae Occur in Africa Eurasia and southestern asia Eye and pinnae are moderately large I Dental formula 2323 11 3424 33 3344 Subfamily Erinaceinae Order Soricomorpha Hedgehogs Molars adapted to omnivorous diet Foot posture is plantigrade Have spines for pelage Panniculus carnosus muscle greatly enlarged o Allows for pulling of skin around body 0 Erection of spines Hibernate or enter estivation 0 Family Siricidae shrews The smallest mammals Snout is long and thin eyes are small pinnae visible Foot posture plantigrade Red pigmentation on teeth 39 Some are venomous Can eat mice much larger than themselves Can cause aches and rashes in humans Extremely voracious killers Small size and high metabolic rate Highest blood oxygen of all mammals 3x more RBCmm3 than humans Heart beat 9001400 beats minute The must eat A LOT Especially in winter 0 Family Talpidae moles Found in North America Europe and Asia Adaptations to fossorial life Eyes beneath skin Long sensitive snout Lack pinnae Fur is lustrous and velvety because it lays in any direction Forelimbs are rotated such that o Phalanges point to the side 0 Palms face backwards o Elbows point upwards 0 Long claws 0 DO NOT DIG WITH INCISORS Condylura cristata 0 Star nosed mole Live in semiaquaticmoist habitat 22 quottentaclesquot on tip of nose Used for touch 0000 25000 Eimers organs 6x number of touch receptors than entire human hand
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