Study guide for test 3

Test 3 covers topics 7, 8 and 9

1. Explain why an organism needs to maintain intracellular ion and water concentrations within a narrow optimal range. Which intracellular functions can be affected by variations in intracellular ion concentrations?
2. Define osmosis and osmotic pressure. Be able to explain how the water and ions will move (in/out the organism) given osmotic concentrations of the organism and the environment. How this movement will affect cell volume? Define isoosmotic, hypoosmotic and hyperosmotic. Be able to tell if the organism is iso-, hypo- or hyperormootic with respect to the environment and when the environment is iso-, hypo- or hyperormootic with respect to the organism.
3. Define vapor pressure deficit (VPD) and be able to calculate it: 1) if given values of the current water vapor pressure and saturation water vapor pressure at a certain temperature; 2) if given values of the current water vapor pressure at a certain temperature and a graph depicting saturation water vapor pressure over the range of temperatures. Explain how the vapor pressure deficit determines the rate of water loss in terrestrial organisms.
4. Explain water potential in plants. Describe how the differences in water potentials between the plant and air or soil affect water gain/loss by the plant. Be able to determine the direction of water movements given water potentials of the plant, soil and air.
5. Describe major challenges for maintenance of the ion and water balance which terrestrial organisms encounter in their environments. Write an equation of water balance for a terrestrial animal and a terrestrial plant and explain each term in the equations. Which are the ways of water gain and water loss in a terrestrial organism?
6. Describe water balances of a desert beetle and a kangaroo rat. What are the MAJOR avenues of water loss and water acquisition in these organisms (remember you equations of the water balance and use those terms).
7. Give examples of adaptations to water conservation (water conservation mechanisms) in plants and animals in arid areas.
8. Give equation of water balance in aquatic organisms; explain each term.
9. Define osmoconformers, osmoregulators and organisms with a mixed strategy of osmoregulation. Give examples animal species belonging to each group. Be able to determine the strategy of osmoregulation when given a graph describing changes in osmotic pressure of the body of an organism against changes in the osmotic pressure of the environment.
10. Explain the mechanisms of isoosmotic cell volume regulation in marine invertebrates. What are the major osmolytes (osmotically active molecules) in cells of marine invertebrate? Describe how marine invertebrates respond to fluctuations in the environmental salinity. Why is isoosmotic cell volume regulation energetically expensive?
11. Explain the mechanisms of ion and water homeostasis in marine bony fish and freshwater bony fish. Are these organisms hypo-, hyper- or isoosmotic to their environment? Explain the main pathways of ion gain/loss and water gain/loss in these organisms. Why is ion and water regulation energetically expensive in marine and freshwater bony fish? How are marine cartilaginous fish (e.g. rays and sharks) different from the marine bony fish from the viewpoint of the ion and water homeostasis?
12. Explain how adaptations to anthropogenic factors (such as pollution) differ from adaptations to natural stressors (i.e. how likely it is that a species will adapt to pollutants, how the rates of environmental change compare between natural and anthropogenic stressors, which type of stressors is more likely to result in extinction).
13. Describe genetic adaptations to heavy metals in plants. Why does the tolerance to heavy metals disappear from the population after a few generations of growing under normal, unpolluted conditions?
14. Describe Dumpton syndrome in marine snails. What is imposex? What is the molecular/biochemical mechanism of imposex? How does it affect reproduction of snail populations? How does Dumpton syndrome allow populations to survive in areas with high TBT concentrations and at what cost?
15. Give definitions of population, abundance and distribution (I will be asking fro definitions that are maximally close to those given in the class).
16. List and explain 4 major groups of factors which limit/determine population distribution. Use an example of the sugar maple to explain how these factors limit distribution of this species in North America.
17. Describe 3 different types of spatial distribution in populations and explain how interactions between individuals in the population affect spatial distribution. Give example of species that have clumped, regular or random distribution and explain why. Give an example of hierarchical spatial distributions (i.e. species that have one type of distribution at large, geographical scale and a different type at small, microhabitat scale).
18. List 3 major methods used to estimate population density. Explain for which type of organisms each of the methods is best suited. Be able to calculate population size if: 1) given the total area occupied by the population, size of a sampling quadrat and number of animals counted within each quadrat (quadrat sampling method); 2) given number of marked individuals released into a population, and number of marked and unmarked individuals during the second capture (Lincoln-Peterson mark-recapture method).
19. List and explain assumptions of the Lincoln-Peterson mark-recapture method of estimation of the population size.
20. List and explain 4 major processes which contribute to the population dynamics (=changing population size). Give definitions of age and a cohort.
21. Define and explain dynamic and static survivorship in the population; give formulas. Be able to calculate dynamic survivorship if given number of individuals of a certain cohort in subsequent years (similar to the in-class example). Be able to calculate static survivorship from a graph of age distribution in the population.
22. Be able to calculate and fill out survivorship tables; explain and be able to calculate x, nx, lx, dx and qx in survivorship tables (similar to the in-class example).
23. Define and explain life expectancy.