The North American pronghorn looks and acts like the antelopes of Africa. But the pronghorn is the only survivor of a family of mammals restricted to North America. Propose a hypothesis to explain how these widely separated animals came to be so much alike.

Lyme disease is caused by infections of the bacterium Borrelia burgdorferi (stained blue in the inset, among red blood cells), which is transferred to humans via blood-sucking bites from the tick, Ixodes scapularis. Lyme disease can cause flu-like symptoms in the short term and more serious illnesses in the long term if not treated.

Why is Lyme disease on the rise in eastern North America?

Researchers have measured a positive correlation between forest fragmentation and incidence of Lyme disease. According to the theory of island biogeography, how do you predict fragmentation will affect species richness?

Lyme disease is caused by infections of the bacterium Borrelia burgdorferi (stained blue in the inset, among red blood cells), which is transferred to humans via blood-sucking bites from the tick, Ixodes scapularis. Lyme disease can cause flu-like symptoms in the short term and more serious illnesses in the long term if not treated.

Why is Lyme disease on the rise in eastern North America?

White-footed mice occupy a broad ecological niche—they occur in most communities regardless of habitat quality. Many other species, like the opossum, are absent from low-quality forest fragments. Based on this information and the data in Question 12, propose a hypothesis to explain the observed relationship between increased forest fragmentation and increased incidence of Lyme disease.

A team of 102 scientists spent a year surveying a small area of the San Lorenzo rain forest in Panama to count the number of species of arthropods living there. After collecting 129,494 specimens—using nets, traps, shovels, tree-climbing harnesses, helium balloons, and other creative gear—it took the team eight years to sort and identify the arthropods. By comparing the number of arthropod species that were common among the 12 plots sampled, the researchers estimated that the total number of arthropods in the whole San Lorenzo forest is 25,000 species.

To come up with this estimate, what's one assumption the researchers had to make about the forest?

Lyme disease is caused by infections of the bacterium Borrelia burgdorferi (stained blue in the inset, among red blood cells), which is transferred to humans via blood-sucking bites from the tick, Ixodes scapularis. Lyme disease can cause flu-like symptoms in the short term and more serious illnesses in the long term if not treated.

Why is Lyme disease on the rise in eastern North America?

A letter to the editor in a local newspaper asserts that 'we cannot afford to preserve natural forests, because we need to use these resources to help humans.' How could you respond to this comment in terms of Lyme disease?

If a forest contains 47,000 kg of plant material, how many kg of tertiary consumers can it support?

Match each of the following species to their role in their respective communities:

Beaver: builds dams in rivers/lakes, significantly altering habitats in the area.

Ochre Sea Star: preys on mussels, preventing them from overpopulating intertidal zones & dominating the habitat.

Red Mangrove Tree: stabilizes shorelines by reducing erosion, provides nurseries for fish in coastal regions.

Consider an ocean community where corals are the most abundant species, where they "build" new habitats using calcium carbonate deposits, creating a coral reef. Which of the following terms can be applied to corals in this community?

Which of the following could be characterized as top-down control in a community?