BIO 311D 2nd Edition Lecture 33 Outline of Current Lecture I Abiotic and biotic factors determine where organisms live II Mammalian reproduction systems link male and female timing III Selection for individual survival and reproductive success can explain most animal behavior Current Lecture I Abiotic and biotic factors determine where organisms live A Interactions between organisms and environment limit the distribution of species a Red kangaroos live in dryer parts of Australia not areas that are hot and wet north or have cool moist winters south b Sea turtles are found in open ocean What adaptations do they have for their marine existence Salt excreting glands to maintain solute homeostasis c Kangaroo Rats are well adapted to dry habitats good kidneys to conserve water d Sequoia trees are found today in limited habitats Redwood timber is valued for its lightweight and resistance to decay and fire They grow in wet cool areas can live over 2000 years and include the world s tallest trees Reproduce asexually and sexually e Monarch butterflies are specialized to fee on milkweed plants migrate seasonally and overwinter in cool mountain sites in Mexico B Distribution of organism is affected by abiotic non living factors temperature and precipitation C Organisms are also affected by biotic factors and interactions D With respect to soil and moisture the distribution of each plant species is distinct from the others Is this due to abiotic or biotic factors How could we test a Biotic predation competition for sunlight Put all the species in the same habitat to see what happens II Mammalian reproduction timing A Population dynamics are affected on death rates and movements into and out of populations B Evolution of reproduction strategies a Asexual a or sexual reproduction C The amniotic egg Reptiles Birds and Mammals has extra embryonic membranes including the amnion allows gas exchange but prevents water loss D Animals time reproduction with seasonal availability of resources a In mammals there must be timely coordination of gamete production mating behavior and in females internal development of offspring in uterus b That s a lot of timing What would mammals need to accomplish this Once fertilization has occurred upper end of the oviduct then the eggs start dividing the blastocyst reaches uterus and the blastocyst implants itself The placenta is site of exchange of nutrients oxygen and waste products between mother and fetus Hypothalamus secretes GnRH gonadotropin releasing hormone Pituitary secretes gonadotropins Ovaries and testes each gonad is two organs in one 1 Produces gametes 2 Secretes sex hormone E Spermatogenesis a Meiosis and differentiation of meiotic product cells into sperm b In the testes certain cells Sertoli control spermatogenesis and others Leydig secrete testosterone F Testes a Hypothalamus secretes GnRh releasing hormone b Gonadotropins stimulate cells making sperm c Gonadotropic stimulate cells secreting testoterone G Which of these acts in a negative feedback loop High circulating testosterone stimulates the pituitary to release less gonadotropin III High circulating testosterone stimulates less release of the gonadotropin H Oogenesis meiosis differentiation or meiotic products into ovum In human oogenesis how many of the four meiotic products become functional egg cells In human oogenesis what is the relative timing of these events a A monthly cycle Follicle cells in ovary nourish eggs and secrete estrogen Ovulation is release of egg from follicle I The ova haploid egg cells from which my children developed were the products of meiosis in follicles of my ovaries When did that meiosis begin When I was a 2 month fetus Selection for individual survival and reproductive success can explain most animal behavior A Selection for individual survival and reproductive success can explain most animal behavior B Recall process of evolution by natural selection genetically based traits can evolve a We can study the proximate mechanisms of behavior hormones nervous system and the ultimate mechanisms relate to reproductive fitness contribution of alleles to next generation C Which of the following aspects of an animal behavior study investigates ultimate factors The number of offspring the territorial male fathers D Behavior of the Northern Mockingbird What are the physiological mechanisms Proximate What are the ultimate factors that led to the evolution of territorial behavior a Affect of hormones on this proximate behavior Experiment add or decrease hormones and observe their behaviors Or add something that blocks or enhance the receptors Also manipulate factors within the environment E Some animal species display selfish behaviors that reduce the reproductive success of their competitors Proximate and ultimate mechanism a A pregnant female house will abort her litter if she encounters pheromones secreted by any male mouse other than the one with whom she mated Ultimate Male mouse would be more aggressive if she was not receptive to him If she was no longer pregnant she could mate with him b When male lions enter a new pride or replace the elder male of their own pride they trey and often succeed in killing any cubs Remove the offspring that weren t sired by him If he kills the other offspring the female would come to him