In your own words, briefly describe the phenomenon of viscoelasticity.
Mastering Biology Questions for Exam #2 Feb 21 1. What studies of the bridled goby, a coralreed fish, and song sparrows of Mandarte island demonstrate Answer: There is a strong densitydependent relationship Why – When population density is high, morality rates are also high relative to fecundity 2. How can human population size keep increasing in spite of decreased fertility rates Answer: Population size will continue to increase as long as the average fertility is above the replacement rate Why – Even with a decrease in fertility rates, populations can still grow at an exponential rate. 3. If 25 individuals were alive in 1955 and 500 existed in 2013, what is r Answer: 0.052 Why – Use calculator 4. If harvesting is not regulated carefully and exploitation is intense, what impact does harvesting have on a population’s age structure Answer: Fewer older individuals will be left in the population; there will be relatively more young individuals. Why – How might harvesting affect the population’s life table and growth rate Answer: IF relatively older individuals are taken, more resources are available to younger individuals and survivorship and fecundity, and the population’s overall growth rate may increase If too many younger individuals are taken, population growth rate may decline sharply as reproduction stops or slows 5. Which is an apt description of a coevoluionary arms race Answer: Consumption driving the evolutionary escalation of species traits. Why – This interaction drives evolution of greater offensive and defensive traits. 6. Coevolutionary arms races occur between _____ Answer: Predators and prey Why – Coevolutionary arms races occur between species that directly affect each other and when at least one species is negatively affected by the other species. 7. Constitutive defencses are ______ Answer: Always present Why – These traits are not produced in response to attack. Feb 28 1. Why might one get mercury poisoning from eating tuna every day, but not from eating sardines from the same water Answer: Tuna biomagnify the mercury Why Tuna eat many sardines that concentrate the mercury in their tissues 2. What is net primary productivity (NPP) Answer: plant biomass or organic material that can be consumed Why – NPP measues the amount of plant material that is available for consumption after plants have used their component of GPP 3. In general, NPP is much higher on land than in oceans. Why Answer: the leading hypothesis is that there is more light available on land than in the ocean Why – water is a filter that absorbs and removes sunlight 4. A study conducted at Hubbard Brook Experimental Forest watershed areas provided experimental evidence that ____ Answer: deforestation increases the rate of nutrient loss from ecosystems Why – Plant roots reduce nutrient losses 5. What factor most affects nutrient cycling Answer: decomposition Why – the rate of decomposition strongly affects the availability of nutrients and the speed at which they cycle 6. What conditions would lead to low decomposition rates in a marine environment Answer: lack of oxygen Why – Stagnant water often has high organic carbon loads 7. Why are atmospheric CO2 concentrations low in the Northern Hemisphere in summer and high in the winter Answer: Photosynthetic activity is increased in the summer relative to the winter 8. Most of the net primary productivity that is consumed is used for what purpose Answer: respiration by primary consumers 9. How would the species richness curves on an island be affected if mainland habitats were wiped out by urbanization Answer: it would lower the rate of immigration and increase the rate of extinction Why – In effect, the island would become more remote 10.Island biogeography theory is based on which two processes Answer: immigration rates and extinction rates Why – This theory predicts species richness as a function of species finding or leaving a certain area. 11.What pattern do ecologists describe when referring to the latitudinal gradient Answer: the frequent trend for there to be more species in communities at lower latitudes Why – birds, mammals, fish, reptiles, and tress show this trend 12.How might a conservation biologist apply the theory of island biogeography in a national park Answer: by ensuring large patches of forest are left undisturbed Why – This would be stimulating mainland habitat March 6 1. Where would a Hadley cell be found Answer: Going from 60 degrees N to 30 degrees N Why – These cells represent the rising and falling of hot and cold air 2. If the earth’s axis were at 90 degrees to the sun, what would be different Answer: There would be no seasons Why – With no variation in day by length, there would be no seasons as we currently define them 3. What terrestrial biome has more biomass belowground than it does aboveground Answer: Temperate grassland Why Grassland plants can have as much as 90% of their biomass belowground 4. Which would you expect to see most reduced in a desert plant Answer: leaves Why Because moisture is scarce, leaves are often very small to prevent water loss.