Biodiversity & Disruptions to Ecosystems (College Board AP® Biology): Exam Questions

Pisaster ochraceus, or the purple sea star, is a species of starfish commonly found in the Pacific ocean. A long-term study was carried out, between 1963 and 1973, into the impact of the presence of P. ochraceus on the local ecosystem. P. ochraceus was removed from several experimental sites, and the resulting effects on some local species was compared with areas where P. ochraceus was still present. Figure 1 below shows some of the results.

Which of the following provides the best explanation for the data shown in Figure 1?

Interdependence between living organisms means that the stability of an ecosystem can be affected by small changes in a single species. Some small changes may result in adaptation.

Which of the following correctly describes an example of adaptation in living organisms?

A group of scientists carried out a study looking at biodiversity in a series of rivers in the UK. The table below contains information about the occurrence of two species of crayfish at different river sites in the UK between the 1970s and the early 2000s.

Which of the following statements correctly describe the data in the table?

Dutch elm disease is fungal disease of elm trees that causes vascular blockages and resulting leaf loss in elm trees native to Europe and North America. It is thought that human factors, such as the import and export of plants, and climate change, are contributing to the spread of the fungus. A group of scientists researched whether some transgenic varieties of elm tree, known as FS5 and AN1, had increased resistance to the fungus. They inoculated three groups of trees (control, FS5 and AN1) with the fungus and observed their symptoms. Some of the results are shown in Figure 1 below. The error bars represent standard error.

Which of the following hypotheses can be accepted?

Throughout geological time the diversity of Earth's ecosystems has changed due to geological factors, the most famous of which is the meteor impact linked to the extinction of the dinosaurs at the end of the Cretaceous period.

Figure 1 shows changes in diversity of each of the limbed vertebrate classes over 400 million years.

Which of the following claims is supported by the data in Figure 1?

Figure 1 below shows the relative biomass and ecological impact of three species, identified as X, Y and Z.

Which of the following statements about the data in Figure 1 is most likely to be correct?

Potato blight, caused by the fungal pathogen Phytophthora infestans, is a highly destructive disease affecting potato and tomato crops worldwide. The disease spreads rapidly under warm, humid conditions and is transmitted through airborne spores or contaminated material. Symptoms of potato blight include lesions on leaves, followed by the spread of infection to the tubers, making them inedible. A group of researchers investigated the effect of fluctuating daily temperatures on the progress of potato blight infection. They measured the growth rate of blight lesions over a range of average temperatures and at different levels of temperature fluctuation. Some of their results are shown in Figure 1. Error bars represent standard deviation.

Which of the following statements about the study described above is correct?

A study looked at the impact of agricultural system on the diversity of root-colonizing fungi, known as arbuscular mycorrhizal fungi (AMF), in summer squash crops. The agricultural systems studied were:

• monoculture: A single crop is cultivated

• polyculture: Several crops species are grown in the same place at the same time

The study measured several factors to assess the impact of agricultural systems on AMF diversity; factors measured included:

• the observed number of different fungal species

• the overall species diversity, taking into account the number of species and the number of individuals of each species; assessed using an index of diversity known as the Shannon diversity index (this is an alternative to the Simpson's index of diversity)

• the percentage of roots that were colonized by AMF

Some of the results obtained are shown in Table 1 below

Table 1. The impact of agricultural system on AMF diversity

Which of the following conclusions is supported by the data in Table 1?