lecture and guest speaker
lecture and guest speaker 408
Popular in Mammalogy
Popular in Wildlife and Fisheries Science
This 4 page Class Notes was uploaded by Dani on Friday January 30, 2015. The Class Notes belongs to 408 at Pennsylvania State University taught by Sheriff in Spring2015. Since its upload, it has received 45 views. For similar materials see Mammalogy in Wildlife and Fisheries Science at Pennsylvania State University.
Reviews for lecture and guest speaker
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 01/30/15
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 0 Photoperioddaylength 0 Very good cue in PREDICTABLE environments 0 Interpreted by pineal gland I When day is short pineal secretes melatonin o Depresses gonadal activity 0 Temperature 0 AMBIENT temperature has little effect 0 Plays role in controlling food supply plants 0 Energy 0 Nutrition I Food availability 0 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 evens with few offspring o Dasyurids family of marsupials I Highly radiated 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 Relativelyunderdeveloped 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 Maleinducedtermination 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 o 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 In the incline phase average of 4 litters per year In decline average of 2 litters per year
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'