Exam 21: Energy Flow and Food Webs

Which statement about keystone species is false?

Refer to the table. By 1993, the Steller sea lion's diet had shifted mainly from _______ in 1976 to _______.

Refer to the table. Table 1 You are studying how energy flows in a food web. The data in Table 1 shows the dietary composition of species in your study area (for species A-H). To read the data table, start at a species in column 1, read to the right across that row to find the number of individuals consumed, then read straight up to determine the species that it consumed. For example, species C consumed 15 individuals of species A. Create a new table (this will be referred to as Table 2) with three columns; species, species consumed, and classification (by diet). Determine which species were consumed by each species. Then, based on this information, classify each species by its diet (e.g., herbivore, etc.). Based purely on the number of species consumed, which species was the most generalist in terms of consumption of other species? How many different species did this generalist consume?

A leaf from a deciduous forest that falls into a large stream and is consumed by insects would be a source of _______ energy for the stream ecosystem.

Refer to the tables. You are studying how energy flows in a food web. The data in Table 1 shows the dietary composition of species in your study area (for species A-H). To read the data table, start at a species in column 1, read to the right across that row to find the number of individuals consumed, then read straight up to determine the species that it consumed. For example, species C consumed 15 individuals of species A. What is unusual about the dietary composition of species E? Give a possible reason for this pattern.

What is the main limitation of removal studies to estimate interaction strength?

Refer to the figure. The figure shows the relationship between the total autotroph biomass in the ecosystem and the ratio of heterotrophic to autotrophic biomass for lakes, coastal ocean, and open ocean. According to the figure, at 1,000 mgC/m² of autotrophic biomass, lakes would be predicted to have a(n) _______ biomass pyramid, coastal oceans would be predicted to have a(n) _______ biomass pyramid, and open oceans would be predicted to have a(n) _______ biomass pyramid.

Refer to the table. Which of the following statements about production efficiencies in consumers is accurate?

According to the studies by Trites and Donnelly, the most likely reason for the decline in the population of Steller sea lions in the Gulf of Alaska is

Higher trophic levels often have _______ concentrations of toxins due to the process of _______.

A predatory wasp that feeds exclusively on herbivorous ants would be an example of a(n) _______ that is part of the _______ trophic level.

Refer to the figure. Which statement about the scorpion in the food web is false?

Which statement about the second law of thermodynamics is true?

Which of the following statements about the bottom-up view of trophic cascades is true?

Refer to the figure. The figure is an example of an inverted _______ pyramid, which is most likely to be found in a(n) _______ ecosystem.

Rabbits consume 4,000 kg of grass per month, and their secondary production is 200 kg per month. If their assimilation efficiency is 50%, what is their consumption efficiency?

Which statement about allochthonous inputs is false?

Drosophila sechellia often eat Indian mulberry plants. Suppose the consumption efficiency of Drosophila is 20%, the assimilation efficiency is 40%, and the production efficiency is 30%. If Drosophila eat 50 kilograms of the plant, how much will be used to produce fly biomass?

Refer to the table. Table 4 Determine the structure of the energy pyramid for your study area. Use the numbers of individuals of each species in Table 4 (for this question, do not include the omnivorous species). Assume that all individuals of all species have the same biomass. a) Collect the data you would need to construct the energy pyramid from Table 4 and use it to create a new table (this will be referred to as Table 5). The columns should be category, number of individuals, number of half the individuals (negative), and number of half the individuals (positive). Under the category column should be the following rows: primary producers, herbivores, primary carnivores, and secondary carnivores. Fill in the rest of the table. b) Use these data to graph the energy pyramid for your study area (this will be referred to as Figure 3). To aid in creating the graph, once you have determined the total number of individuals in each category, divide the number of individuals by half. One half will be plotted on the left of the graph (as negative) and one half will be plotted on the right of the graph (as positive). Your graph should be centered around a y-axis at 0. Label each step in the energy pyramid with the category name (e.g., herbivores) from the table. c) Based on Figure 3, what type of ecosystem are you studying?

The production efficiency of an herbivore is equal to _______ divided by _______.