Ecosystem services are the benefits provided to humans by the natural environment and healthy ecosystems. Economists have valued these global benefits at an estimated US$33 trillion–though many say the actual value is almost certainly much larger. If not for these ecosystem services, we would have to find alternate ways to achieve these benefits in order to survive. Which of the following ecosystem services have economic value? (Select all that apply.)

______ is a process in which organisms rapidly diversify into a variety of new forms. This happens particularly when environmental changes make new resources available, such as a mass extinction event.

The placement and development of two bones of the reptilian jaw are very similar to that of two bones of the mammalian middle ear, which probably evolved from the reptile bones. The similarity of these bones is an example of

When scientists refer to the “environment,” which of the following features are included? (Select all that apply.)

The specimens are arranged in three rows that read: Bottom Row: Mussels, Giant Tubeworms, and Shrimp. Middle Row: Zoarcid Fish and Dandelion Siphonophores. Top Row: Octopuses and Blind Crabs. In the bottom row, there is one arrow from Mussels to Octopuses; there is one arrow from Giant Tubeworms to Zoarcid Fish; and there are three arrows from Shrimp to Zoarcid Fish, Dandelion Siphonophores, and Blind Crabs. In the middle row, there is one arrow from Zoarcid Fish to Octopuses; and there is one arrow from Dandelion Siphonophores to Blind Crabs. In the top row, there is one horizontal arrow from Blind Crabs to Octopuses. The food web above represents feeding relationships in a biological community near a deep-sea hydrothermal vent. Hydrothermal vents are geysers on the seafloor that gush super-heated, mineral-rich water. The seawater surrounding hydrothermal vents typically contains carbon dioxide (CO2), molecular hydrogen (H2), hydrogen sulfide (H2S), and methane (CH4). Sunlight, however, fails to reach the seafloor where deep-sea hydrothermal vents are located. As part of an investigation, researchers collected living specimens from an area near a deep-sea hydrothermal vent. Mussels in the collection were found to be dependent on molecular hydrogen in seawater. Also, the researchers discovered multiple species of bacteria living in the gills of the mussels. Mussels use gills for filter-feeding and gas exchange with the surrounding seawater. On the basis of their experimental results, the researchers hypothesized that some bacteria living in the gills of the mussels are capable of chemosynthesis. To refine their model of deep-sea biological communities, the researchers investigated areas of the seafloor that are distant from any active hydrothermal vents. Which of the following is the best interpretation of the observation that some octopus species are only found near active hydrothermal vents?

The deep ocean floor communities contain very little life. In constant darkness, the water at these depths hovers around 2°C. Sparsely distributed in this environment are hydrothermal vent ecosystems. Superheated water streams out of the vents at temperatures approaching 400°C. These waters are rich in inorganic materials, including carbon dioxide and hydrogen sulfide. Hydrothermal vent zones have a density of organisms 10,000 to 100,000 times greater than found on the surrounding seafloor. Scientists have studied these vents to determine the energy source for these communities and the identity of the primary producers in the perpetual darkness of the ocean floor. As expected, they found a total absence of photosynthetic organisms at all vents, identifying mats of bacteria as the producers of the carbon compounds that are used by the rest of the community for growth, repair, and as an energy source. Which of the following describes how the vent bacteria harvest energy to produce organic compounds for use by the vent community?

The Fisher’s lovebird builds it nest with thin strips of vegetation that it cuts with its beak. A closely related species, the peach-faced lovebird, cuts shorter strips for its nests. When these two species are interbred, the hybrid offspring cut strips of intermediate length for their nests. These observations suggest that this aspect of nest building is

A species of snail lives in the intertidal zone along the coast of New England. The dark-colored variety of the species is more common in northern New England, where the water is cooler, the light-colored variety is more common two hundred miles away in southern New England, and both varieties are commonly found together in central New England. Which of the following best explains the observed distribution pattern of the snails?

  From left to right, the taxa are Sharks, Ray-finned fish, Amphibians, Primates, Rodents and rabbits, Crocodiles, and Dinosaurs and birds. From the base, a line extends to the right and passes through a pink square labeled 1 Vertebrae before reaching a branch point. The left branch leads upward to Sharks. The right branch continues to the right, passing through a pink square labeled 2 Bony skeleton before reaching another branch point. The left branch leads upward to Ray-finned fish. The right branch continues to the right, passing through a pink square labeled 3 Four limbs before reaching another branch point. The left branch leads upward to Amphibians. The right branch continues to the right, passing through a pink square labeled 4 Amniotic egg before reaching another branch point. At this branch point, the left branch continues upward, passing through a pink square labeled 5 Hair before reaching another branch point. The left branch from this point leads upward to Primates, and the right branch leads upward to Rodents and rabbits. The right branch from the Amniotic egg branch point continues upward, passing through a pink square labeled 6 Two post-orbital fenestrae before reaching another branch point. The left branch from this point leads upward to Crocodiles, and the right branch leads upward to Dinosaurs and birds. On this cladogram, short pink lines are used to represent ______.

Populations of Successive Trophic Levels Level Population 4 4 3 360 2 780 1 5,782 In a simple ecosystem, a census of the populations in four successive trophic levels was taken as shown above. If level 1 is composed of photosynthetic autotrophs, then the trophic level with 780 individuals will most likely represent