Ch. 34 Mastering Biology

Why do bodies of water tend to moderate climate?

the hydrogen bonding in water gives it a high specific heat

Which of the following statements best represents the hypothesis-based approach to scientific inquiry?

A hypothesis should lead to a prediction that can be tested.

Which of the following is true of most animals commonly found in our homes?

they are flat and have poor eyesight

Temperature, precipitation, sunlight, and wind are the major components of __________

climate

The study of the interaction of organisms with each other and their environment involves non-living factors, also called _________________, and living factors, which are referred to as __________________.

abiotic components; biotic components

Which of the following is characteristic of oligotrophic lakes?

few littoral plants and a low density of phytoplankton

Can you match each labeled location on the map with its description? Drag the labels at the left to their appropriate targets on the right. 1. The biome found in location __ experiences a large annual temperature range and is home to many trees that lose their leaves seasonally. 2. The biome found in location __ has mild, rainy winters and hot, dry summers due to cool ocean currents circulating offshore. 3. In location __ ascending moist air releases much of its moisture as it cools, resulting in abundant rainfall. 4. In location __, descending dry air absorbs moisture, resulting in an arid climate. 5. The biome in location __ is characterized by permafrost and is home to large, well-insulated herbivores such as musk oxen and caribou. 6. The biome in location __ is characterized by low precipitation and cold winter temperatures. Its abundant grasses support large grazing animals and many small mammals and invertebrates. 7. In location __, temperature is warm all year round. It is characterized by grassland, scattered trees, large herbivores and their predators, and frequent fires.

1. D 2. B 3. E 4. F 5. A 6. C 7. G

Which of the following choices correctly pairs a terrestrial biome with some of its characteristics?

taiga ... very cold winters, short growing season

Which of the following areas of study focuses on the exchange of energy, organisms, and materials between ecosystems?

landscape ecology

Which hierarchical level is represented by a survey of students and their habits?

population

A species with which of the following characteristics is most likely to be successful in our homes?

Does well in a stable environment.

McCarthy decided to use the 2 x 2 design from Part B. The design of their experiment allowed them to test their hypothesis: Increased CO2 in the atmosphere will increase plant growth, and this increase will be greatest when there is an abundance of water. Using what you learned about the equation for photosynthesis and McCarthy's hypothesis, make predictions for the tree growth at each site. One has already been filled in for you.

CO2 level, moisture level: ambient, dry - low growth high, dry - medium growth high, wet - high growth

Can you complete this concept map identifying the types of aquatic biomes? Drag the labels from the left to the correct locations on the right to complete this concept map about aquatic biomes.

a - marine b - freshwater c - coral reefs d - wetlands e - intertidal zones f - estuaries g - lakes and ponds h - marshes

What is the largest hierarchical level that global warming affects?

biosphere

You are an ecologist interested in studying the youngest biome. Which of the following do you choose?

indoors

You are an exterminator working on a new bait for German cockroaches. Which of the following would likely be best for you to avoid choosing due to its known ineffectiveness?

sugar

You wish to study the evolution of Exophiala from its outdoor existence to life in human homes. Where should you collect your outdoor samples?

tropical fruits

WHAT IF? If the direction of Earth's rotation reversed, the most predictable effect would be

winds blowing from west to east along the equator.

At the end of an experiment, a scientist's work is not over. Regardless of whether a scientist supports or rejects his or her hypothesis, good experiments lead to new hypotheses and new experiments. The global amount of CO2 in the atmosphere is rising, so there are potentially global implications for McCarthy's study. Take a look at the figure below. Given that McCarthy supported her hypothesis, can you make predictions for how rising levels of CO2 might influence plant growth in different biomes?

lowest growth to highest growth: desert -> grassland -> temperate forest -> tropical rain forest

After nutrient enrichment from sewage contamination, a lake often becomes inhospitable to fish. Why?

Nutrient input to a lake causes the explosive growth of algal and cyanobacterial populations. Decomposition of dead algae and cyanobacteria by bacteria results in the depletion of oxygen in the water, which leads to the death of fish.

Can you place the terms in the appropriate sentences? Drag the terms to their correct locations in the paragraph. Not all terms will be used.

In the ocean, communities of plants, algae, and animals are distributed according to the depth of the water and distance from shore. Light reaches organisms in the PHOTIC ZONE, where microscopic PHYTOPLANKTON and multicellular algae provide food for the animal community. Light levels in the APHOTIC zone are too low to support photosynthesis. The seafloor is called the BENTHIC REALM. Fishes and marine mammals swim in open water known as the PELAGIC REALM. A distinctive biome called a(n) ESTUARY is found where a freshwater stream or river merges with the ocean.

W. J. Fletcher, of the University of Sydney, Australia, reasoned that if sea urchins are a limiting biotic factor in a particular ecosystem, then more seaweeds should invade an area from which sea urchins have been removed. To isolate the effect of sea urchins from that of a seaweed-eating mollusc, the limpet, he removed only urchins, only limpets, or both from study areas adjacent to a control site. Fletcher observed a large difference in seaweed growth between areas with and without sea urchins. Removing both limpets and urchins resulted in the greatest increase in seaweed cover, indicating that both species have some influence on seaweed distribution. But since removing only urchins greatly increased seaweed growth whereas removing only limpets had little effect, Fletcher concluded that sea urchins have a much greater effect than limpets in limiting seaweed distribution. Compared to the control (red line), in which both sea urchins and limpets are present, removing limpets alone (blue line) did not have much effect. This might suggest that limpets have little effect on seaweed distribution. However, seaweed cover increased much more when both urchins and limpets were removed (purple line) than when only urchins were removed (green line). How might you explain this result?

When only urchins were removed, limpets increased in abundance and reduced seaweed cover.

Which of the following options lists the ecological hierarchy in the correct order, from largest to smallest?

biosphere; ecosystem; community; population; organism

A scientist is studying how sea slugs respond to predators. Which hierarchical level of ecology does this represent?

community

It is important to remember that behind every hypothesis statement, there are assumptions, knowledge, and theories. When developing their hypothesis, McCarthy and her colleagues started by considering the chemical equation for photosynthesis. 6CO2 + 6H2O + Energy → C6H12O6 +6O2 Carbon dioxide + Water + Sunlight → Carbohydrate + Oxygen As photosynthesis occurs, the reactants and energy on the left are used, generating the products on the right. A plant with access to more reactants can grow more than a plant with access to fewer reactants. Suppose you are able to manipulate a plant's access to components in the photosynthesis equation. Drag each label to the appropriate bin to predict how that action will affect plant growth. For each increase or decrease, assume that every other component of the photosynthesis equation is unlimited.

decrease plant growth - decrease sunlight, decrease CO2, decrease H2O no effect - increase O2, decrease O2, increase C6H12O6, decrease C6H12O6 increase plant growth - increase CO2, increase sunlight, increase H2O

Suppose that a few individuals of a lizard species are transported on a log that floats from the mainland, where the lizard is abundant, to a distant island, where prior to this event no lizards (of any species) existed. The environmental conditions on the island are similar to those on the mainland. A small population of this lizard becomes established on the island; within a few years, allele frequencies in the island population differ greatly from those in mainland populations. Which of the following is the most likely cause of the genetic differences between the island and mainland populations?

genetic drift

Note that the hypothesis considers two variables that could influence plant growth--water and CO2. Often when we consider experimental design, we talk about designing a controlled experiment where we change only one independent variable (often referred to as the treatment), so that we can be sure that any results are a consequence of that independent variable. (The results are measured as changes in a dependent variable, which depends on the independent variable.) However, scientists can conduct experiments where more than one variable changes. When a scientist conducts an experiment where there are two independent variables with two levels (such as high and low) this is called a two-by-two (2 x 2) design. McCarthy and her colleagues used a 2 x 2 design for their experiment. To properly conduct their experiment, they needed to choose treatment combinations that allowed them to have high and low levels of CO2 and high and low levels of moisture, such that they had all 4 possible combinations of these variables. They conducted their experiment at the Duke University Forest in North Carolina. At the forest, previous researchers had made large machines that pump CO2 into defined areas of the forest. There were also dry locations, moist locations, and locations that had more sunlight than others due to the forest canopy. Suppose you are helping McCarthy choose her sample sites. You have the resources to conduct the study at only 4 sites. Pick the 4 sites that allow all 4 possible treatment combinations, while controlling for sunlight. Drag a check mark to each site you would use, and drag Xs to the sites you would not use. You should end up placing 4 check marks and 8 Xs. Labels can be used more than once.

high CO2: ✅☀️☀️💧 ✅☀️☀️💧💧💧 ambient CO2: ✅☀️☀️💧 ✅☀️☀️💧💧💧

The oceans affect the biosphere in all of the following ways except

regulating the pH of freshwater biomes and terrestrial groundwater.