BIO 311D 2nd Edition Lecture 33 Outline of Current Lecture I. Abiotic and biotic factors determine where organisms liveII. Mammalian reproduction systems link male and female timingIII. Selection for individual survival and reproductive success can explain most animal behaviorCurrent LectureI. Abiotic and biotic factors determine where organisms liveA. Interactions between organisms and environment limit the distribution of speciesa. 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 happensII.Mammalian reproduction timingA. Population dynamics: are affected on death rates, and movements into and out of populationsB. Evolution of reproduction strategies. a. Asexual a or sexual reproductionC. The amniotic egg (Reptiles, Birds and Mammals) has extra-embryonic membranes, including the amnion, allows gas exchange but prevents water lossD. Animals time reproduction with seasonal availability of resourcesa. In mammals there must be timely coordination of gamete production, matingbehavior, 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. Spermatogenesisa. Meiosis and differentiation of meiotic product cells into sperm.b. In the testes, certain cells (Sertoli) control spermatogenesis and others (Leydig) secrete testosterone F. Testesa. Hypothalamus secretes GnRh releasing hormoneb. Gonadotropins stimulate cells making spermc. 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.- 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 a2 month fetus III. Selection for individual survival and reproductive success can explain most animal behaviorA. Selection for individual survival and reproductive success can explain most animal behaviorB. Recall process of evolution by natural selection genetically based traits can evolvea. 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 fathersD. 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 decreasehormones 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