Biological Principles 2 -- HW#54

1.      You awaken to find yourself lying on the bare ground, dirty and injured. In the dim light, you can make out wreckage around you and surmise that you have survived a plane crash. Over the next few days, you wander the hot, humid area and find an amazing number of different plant and insect species. You are able to trap and eat several rodent size mammals, but do not see any larger mammals. Into what biome did your plane crash? Tropical rain forest.

2.      What will be a consequence if current predictions of global warming are accurate? Organisms will need to migrate or adapt quickly in order to survive.

3.      Temperature is perhaps the most important factor in the distribution of organisms because most organisms are unable to regulate their body temperature precisely.

4.      Based on the three cell model of global air circulation shown in the figure above, where would you be most likely to find a plant species that is very drought tolerant, but not cold tolerant? Between 20º and 30º latitude.

5.      The same biome cannot occur on more than one continent. False

6.      Organisms are adapted to the environmental conditions to which they are exposed. The diversity of organisms that is found in any particular area is largely determined by the limiting abiotic factors of that region. Match the following adaptation, habitat characteristic, and distribution characteristic with the limiting abiotic factor that is most directly responsible for it.

·         Reptiles, which are ectothermic, are more common and diverse in the southern U.S. than in the northern U.S. and Canada. Temperature

·         Acid rain has caused large die-offs of trees in the Northeastern U.S. due to the interaction of pollutants with natural atmospheric gases. pH

·         Wave action along the coast of California has led to the evolution of bivalves and other tidal creatures with a means of anchoring themselves to a surface to prevent the waves from washing them out to sea. Wind

·         Plant growth proliferates after a heavy rain in the desert southwest. Water availability

·         In order to maintain osmotic balance, freshwater protists must actively pump water out of their bodies into the surrounding water. Salinity

·         Red algae, which grow in deeper water than most green algae, utilize the blue-green end of the visual electromagnetic spectrum for photosynthesis. Light availability

7.      Lakes with elevated dissolved nutrients and low water clarity are called eutrophic.

8.      Explain the differences between experimental and observational studies by filling in the blanks with the correct terms.

·         Experimentation is not always possible when studying natural phenomena. Ecologists frequently must rely on systematic observations, which can provide insight into the presence or absence of correlations.

·         These data provide scientists with an understanding of how two variables are related to one another. However, this does not mean a cause and effect relationship has been established.

·         It is possible that a relationship between the variables of interest may be caused by a third unknown variable. Scientists therefore often manipulate experimental variables in order to test their hypotheses.

·         The data gathered from experimental groups can then be compared to data from non-manipulated control groups.

·         If there is a difference between the groups that is not likely due to chance alone, it is considered statistically significant. Scientists can use statistics to show their confidence in making conclusions about cause and effect.

9.      Which of the following is a characteristic of tundra? Permafrost.

10.  Quiver trees are succulents in the Karoo that are suffering from the effects of global warming. How do Quiver trees cope in response to the extreme water stress brought on by climate change? They abort their flowers.

11.  What will happen within the ecosystem of the Karoo if the succulents die out? The soil will erode giving away to a sandy wasteland.

12.  If the succulents of Karoo die out, would the effect on the habitat be similar to deforestation? Yes; the loss of succulents is similar to deforestation in that both would result in the destruction of the habitat.

13.  Plants such as the Quiver Tree have adapted to living in dry conditions over many thousands of years. If temperatures continue to increase as they have over the past few decades, what will be the most likely fate of most individual quiver trees? Individuals trees will die.

14.  What is the most important idea in this video clip? Climate change can have devastating effects on the plant life and landscape in an area.

15.  Ecology           is the study of interactions between organisms and their environment.

16.  Climate affects the distribution of organisms. Indicate true or false, that the following statements accurately describe either climatic variables or how these variables impact the latitudinal variation in organismal distribution.

·         Warm air rises. True

·         Cold air holds more moisture than warm air. False

·         As air rises in the atmosphere it cools down. True

·         When air cools down it releases moisture in the form of precipitation. True

·         Warm, wet air circulates away from the equator as dry cool air comes up behind it. False

·         As air descends it cools down and picks up moisture, making the air more humid. False

·         Sunlight is more direct and intense at the equator than at the poles. True

·         Tropical rainforests near the equator are characterized by high levels of annual rainfall and relatively constant annual temperatures. True

·         At 30° latitude there is ample precipitation in all seasons, with extreme seasonal variation in temperatures. False

17.  Match the descriptions with the appropriate biomes.

·         moderate annual rainfall, variation in annual temperature, mammals frequently hibernate part of the year, reptiles relatively uncommon. Temperate deciduous forest

·         very abundant annual rainfall, high year-round temperatures, closed canopy, sparse understory, epiphytes common, extreme organismal diversity. Tropical rain forest

·         abundant rainfall, temperatures seldom below freezing, coastal areas, large evergreens, high diversity of mammals, birds, and reptiles. Temperate rain forest

·         moderate annual rainfall, very cold temperatures, conical evergreen trees, understory is sparse. Temperate coniferous forest

·         low annual precipitation, permafrost, short growing season, fauna is more diverse in summer than winter. tundra

·         annual rainfall varies from 25 to 100 cm, cold winters and very warm summers, large mammals, prominent vegetation is grasses, no trees. Temperate grasslands (prairie)

·         annual rainfall between 50 to 130 cm, with extensive dry season, high daily temperatures year round, large mammals, frequent fires. Tropical grasslands (savanna)

·         low annual precipitation, daily temps ranging from around freezing at night to 50°C at night, plant life includes cacti and other plants that store water, many ectotherms. Hot desert

·         substantial annual rainfall, high year-round temperatures with a distinct extended dry season, dense understory, high animal diversity. Tropical deciduous forest

·         low annual precipitation frequently in the form of snow, high daytime temps in summer, around freezing in winter, low plant diversity. Cold desert

18.  Ecologists approach the study of organisms and their interactions with the environment from many different levels.  Categorize each of the following questions according to whether it would most likely be posed by an organismal, population, community, or ecosystem ecologist.

·         What enables a penguin to stay underwater for so long during a dive? Organismal ecologist

·         How do Blue Jays learn to avoid eating poisonous Monarch butterflies? Organismal ecologist

·         Why do hummingbirds expend energy defending a backyard bird feeder when there is more than enough 'nectar' in the feeder for multiple hummingbirds? Organismal ecologist

·         Why does a Belding's Ground Squirrel give an alarm call in the presence of a predator instead of just hiding or protecting itself? Organismal ecologist

·         How do food shortages during the winter vs. the summer affect the population density of the Gray Wolf? Population ecologist

·         Will the human population continue to grow exponentially for the foreseeable future? Population ecologist

·         How many Northern Saw-whet Owls are migrating through the Midwest as compared to the Northeast? Population ecologist

·         How does the intensity of a fire impact the ability of a prairie to rebound? Community ecologist

·         Beavers build a dam in a creek, and after a heavy rain a nearby neighborhood becomes flooded as the water is prevented from flowing downstream.  What would be the impact on local wildlife of the removal of the beaver dam? Community ecologist

·         Medium and Large Ground-Finches do not differ in bill size in areas of allopatry, but they have significantly different bills sizes on an island where they are sympatric.  Why are the relative bill sizes different in areas of allopatry vs. areas of sympatry? Community ecologist

·         How much carbon is tied up within the biomass of the trees of a tropical rainforest and how does that impact the availability of carbon for new growth in the area? Ecosystem ecologist

·         How does the encroachment of phragmites, an invasive plant, threaten the organisms within a newly established wetland? Ecosystem ecologist

·         How does deforestation influence the nutrient content of the soil and nearby water source? Ecosystem ecologist

19.  A scientist is studying several areas along an elevation gradient. Her study involves prescribed burns (purposefully set, low-intensity fires) in the different areas, followed by a comparison of the type and abundance of organisms that colonize them over the next ten years. What scale best describes her study? Community ecology

20.  The Panamanian golden frog is in decline because of outbreaks of a fungus, which are being driven by global climate change.

21.  Mark the following statements on global warming as true or false.

·         The increase in greenhouse gases, in part due to the industrial revolution, is correlated with an increase in average annual global temperatures. True

·         Atmospheric levels of CO2 are fluctuating widely year-to-year, resulting in changes in atmospheric pressure and fluctuating average annual global temperatures. False

·         CO2 and other greenhouse gases trap heat close to the earth’s surface, such that the more CO2 in the atmosphere the higher the average annual global temperature. True

·         CO2 is a toxic waste product from burning fossil fuels and cannot be utilized by living organisms and hence has been building up in the atmosphere. False

·         Greenhouse gases are naturally occurring in the atmosphere, and without them the earth would not be warm enough to sustain life. True

·         Scientists are not worried about extinction rates associated with global warming as the rates are not likely to be impacted by global warming since populations will shift their ranges or adapt to the new environmental conditions over time. False

22.  Over the next century, how do you think the effects of global climate change will compare for species adapted to extreme heat (tropical and hot desert species) versus those adapted to extreme cold (polar species)? Both tropical/hot desert and polar species will be impacted, but polar species are more likely to go extinct because they cannot migrate any further poleward.

23.  The Cerulean warbler is a songbird that breeds in the eastern and middle US and winters in Central America. Its numbers have been rapidly declining over the past 50 years. You are interested in the reason(s) for this rapid decline and set about to make observations and gather data. The graph above shows data you collected on the abundance of Brown cowbirds (nest parasites) and Cerulean warblers at various locations. Based on a visual inspection of the graph, what can you conclude? The abundance of Brown cowbirds shows a negative relationship with Cerulean warbler abundance.

24.  Match the biomes with the appropriate description.

·         Intertidal zone

1.      Land meets sea, daily cycle of tides

2.      Huge variation in temperature, light intensity, and availability of seatwater

·         Coral reef

1.      Warm tropical water with penetrating sunlight

2.      High biodiversity of aquatic organisms

·         Open ocean

1.      Pelagic zone

2.      Phytoplankton base of the food chain, zooplankton

·         Lentic habitats

1.      Still, open water, inland lakes, often deep water

2.      Nutrient accumulation and temperature variation

·         Lotic habitats

1.      Flowing water, well aerated with uniform temperature

·         Wetlands

1.      Areas regularly saturated by surface or ground water

2.      Marshes, swamps, bogs