Chapter 51, Problem 13
The carnivorous plant Nepenthes bicalcarata ('fanged pitcher plant') has a unique relationship with a species of ant—Camponotus schmitzi ('diving ant'). The diving ants are not digested by the pitcher plants, but instead live on the plants and consume nectar. Diving ants also dive into the digestive juices in the pitcher, swim to the bottom, and capture and consume trapped insects, leaving uneaten body parts and ant feces behind. What nutritional impact do the ants have on fanged pitcher plants? Do the pitcher plants derive any nutritional benefit from this relationship? Based on the background information presented here, does the relationship between diving ants and pitcher plants appear to be mutualistic? Explain.
Video transcript
The carnivorous plant Nepenthes bicalcarata ('fanged pitcher plant') has a unique relationship with a species of ant—Camponotus schmitzi ('diving ant'). The diving ants are not digested by the pitcher plants, but instead live on the plants and consume nectar. Diving ants also dive into the digestive juices in the pitcher, swim to the bottom, and capture and consume trapped insects, leaving uneaten body parts and ant feces behind. What nutritional impact do the ants have on fanged pitcher plants? Do the pitcher plants derive any nutritional benefit from this relationship? Researchers tested the hypothesis that the relationship between diving ants and pitcher plants is mutualistic (i.e., both species derive a nutritional benefit). To do so, they compared leaf surface area (as a measure of overall growth) in two sets of pitcher plants: plants with diving ants and plants without. The results are shown in the graph. The P values indicate whether there is a significant relationship between the size of the host plants and the surface area of the host plants' leaves. Based on this graph, what conclusions can be drawn about the impact of diving ants on overall plant growth?
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. Rather than measuring the entire 6000-hectare (ha) forest, the researchers sampled arthropod diversity by intensively collecting as many arthropods as they could in 12 plots that measured 20 m×20 m square. If 1 ha=10,000 m2,, how many hectares of forest did they sample in all? a. 20 m×20 m×12=4800 ha b. 4800 m2×10,000 m2/1 ha=48,000,000 ha c. 20 m×20 m=400 ha d. 4800 m^2 x 1ha/10,000 m^2 = 0.48 ha
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. The graph below shows some of the data for the major arthropod groups collected. Notice that the scale on the y axis is logarithmic to make both small and large numbers legible on the same graph. For example, there are about 400 species of spiders, but only 40 species of bees. About how many arthropods were found in total? About what percentage of these were beetles?
Lyme disease is caused by infections of the bacterium Borrelia burgdorferi (stained blue in 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? Deer are hosts of ticks but are not reservoirs of B. burgdorferi—their immune systems detect and kill the bacterium. But a tick with a prior bacterial infection can consume a blood meal from a deer and then bite and infect a human. The fitness effects of a deer on B. burgdorferi can be summarized as: a. + because the deer supplies the bacterium with food. b. − because the deer kills the bacteria in its blood. c. + because the deer feeds and disperses the tick that can then infect a human with the bacterium. d. − or + depending on whether the deer is the tick's last host.
The carnivorous plant Nepenthes bicalcarata ('fanged pitcher plant') has a unique relationship with a species of ant—Camponotus schmitzi ('diving ant'). The diving ants are not digested by the pitcher plants, but instead live on the plants and consume nectar. Diving ants also dive into the digestive juices in the pitcher, swim to the bottom, and capture and consume trapped insects, leaving uneaten body parts and ant feces behind. What nutritional impact do the ants have on fanged pitcher plants? Do the pitcher plants derive any nutritional benefit from this relationship? Explain why carnivorous and parasitic plants are most common in nutrient-poor habitats.
Lyme disease is caused by infections of the bacterium Borrelia burgdorferi (stained blue in 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?