Biology Question- Chapter 54

What does species richness refer to? Select True or False for each statement. -The number of species in an area -The evenness of species in an area -the functional diversity of a species in an area -the phylogenetic diversity of species in an area

True False False False

If you understand species area curves, you should be able to use the equation describing the line in Figure 54.9 to predict the species richness of an island in the Bismarck Archipelago with an area of 5000km^2.

Using the equation S = (18.9)A^(0.15), plug in 5000km^2 for A and solve for S such that S = 68 species.

Pesticides are generally ineffective in killing coffee berry borers. Ecologist Daniel Karp and colleagues conducted a study in Costa Rica to determine if natural predators like birds reduce the beetle population. The researchers selected 12 control plots and used nets to exclude birds from 12 similar treatment plots. What is the take home message of the graph?

When birds are excluded, the percentage of berries with borers approximately doubled. The difference is considered statistically significant, because the P value is less than 0.05.

Based on what you have learned in this chapter about global trends in terrestrial ecosystems, what is currently the largest threat to the wet tropical forests in Central America? a. habitat destruction, such as the clearing of forests for coffee plantations b. exotic species, such as the introduction of coffee berry borers c. pollution, such as the use of pesticides in coffee plantations d. climate change, such as changes in precipitation patterns

A

What proportion of threatened terrestrial species experience habitat destruction or degradation?

About 50 percent

Explain how you could measure biodiversity in the rain forests of Borneo at the genetic, species, and ecosystem levels.

At the genetic level, you could measure the genetic diversity of the orangutan population by comparing DNA sequences obtained from blood or feces samples. Alternatively, you could use environmental sequencing to look at the genetic diversity of soil organisms. At the species level, you could monitor the species richness of trees, birds, mammals, and other groups, and identify any changes in species richness. At the ecosystem level, you could measure the ability of the growing forest to retain nutrients in the soil, prevent erosion, trap carbon, increase the prevalence of cloud cover and rain, and other functions.

What community property does the red arrow in the model represent? a. low resilience b. high resilience c. low resistance d. high resistance

B

The locations of the fragments and study plots were assigned randomly. Why was this step important?

Because the treatments and study areas were assigned randomly, no bias is involved in picking certain areas that have unusual biomass or species diversity. They should represent a random sample of biomass and species diversity in fragments of various sizes versus intact forest.

Biologists claim that the all-taxa survey now under way at the Great Smoky Mountain national Park in the United States will improve their ability to estimate the total number of species living today. Discuss the benefits and limitations that this data set will provide in understanding the extent of global biodiversity.

By comparing the number of species estimated to reside in the park before and after the survey, biologists will have an idea of how much actual species diversity is being underestimated in other parts of the world- where research was at the level of Great Smoky Mountains National Park before the survey. The limitation is that it may be difficult to extrapolate from the data- no one knows if the situation at this park is typical of other habitats.

The population size of mountain pine beetles in the American Northwest has long been held in check by freezing temperatures during the winters. As winters warm, populations of pine beetles are increasing killing whitebark pine forest. Grizzly bears rely on the nuts of whitebark pine trees. Do you think climate change is affecting the fitness of the grizzly bear population? a. No, because climate change is not a problem yet b. No, because climate change is affecting the beetles, not the bears. c. Yes, because climate change is decreasing the food supply of the bears, which means they will be less strong. d. Yes, because climate change is decreasing the food supply of the bears, which is likely to reduce their ability to survive or reproduce.

D

What is a biodiversity "hotspot"? a. an area where an all-taxon survey is under way b. an area where an environmental sequencing study has been completed c. a habitat with high NPP d. an area with high species richness and high threat to those species

D

Design an experiment to test the hypothesis that the tropical forest of Borneo is more effective at building soil, retaining soil nutrients, and minimizing soil erosion than the oil palm plantations are.

Establish several study plots in an area of Borneo where some of the forest has been converted to oil palm plantation but the adjacent forest is still intact- half of the plots in the plantation and half in the native tropical forest. Monitor soil depth, soil nutrient levels, precipitation, and stream sediment levels regularly, and compare after several years.

Explain how the planting of trees in poor city neighborhoods could decrease the inequality in physical and mental health among people in poor and wealthy neighborhoods.

Exposure to nature has a number of physical and mental health benefits, such as reduced stress and depression and reduced rates of obesity and diabetes. Since poor neighborhoods tend to have less access to natural areas than do wealthy city residents, planting trees in poor neighborhoods could help to decrease health inequality among poor and wealthy people.

Explain why fragmentation reduces habitat quality and can lead to the reduction of genetic diversity.

Fragmentation reduces habitat quality by creating edges that are susceptible to invasion and loss of species, due to changed abiotic conditions. Genetic diversity can be reduced inside fragments as inbreeding occurs, exposing rare deleterious alleles diversity via genetic drift.

Explain why the high biodiversity of tropical forests leads to high productivity, in terms of efficient resource use, when compared to oil palm plantations.

If many species are present, and each uses the available resources in a unique way, then a larger proportion of all available resources should be used-leading to higher biomass production.

Why is the common phrase "humans and animals" not accurate in biology? Suggest one way that a more scientific outlook could boost conservation efforts.

In biology, humans are a type of animal, so saying humans and animals" is incorrect, like saying "apples and fruit." Switching from a "humans and animals" to a "humans and other animals" worldview could encourage conservation in a number of ways. For example, if people feel more closely related to other animals, we may be more motivated to prevent extinctions. Likewise, if people feel more closely related to other animals, it may seem more obvious that humans are part of ecosystems rather than separate from nature, increasing motivation to reduce our negative impacts on ecosystems.

Draw a simple model to compare the relative species richness and species diversity of these two coffee plantations: one is clear-cut and planted with only coffee shrubs, the other retains some natural forest. For symbols, use a few letters to represent different species of plants and a few numbers to represent different species of animals in a square 1-ha plot.

In this example, species richness = 3 in the clear cut plantation and = 12 in the plantation including native forest. The species diversity in the clear-cut plantation is very low because it is dominated by one species, coffee. The species diversity is higher in the second plot, due not only to the higher number of species (including birds) but also the the more even distribution of abundance among species.

Evaluate this statement: Leaving some natural forest in and around coffee plantations is a "win-win" situation- a win for ecosystems and a win for farmers.

It does look like a win-win situation. leaving more natural forest increases the biodiversity at the genetic, species, and ecosystems levels, increasing the change of resilience and ecosystem function. Leaving some of the natural forest is a win for farmers because the forest provides ecosystem services, such as pest management, that farmers rely on for a successful business.

If you decided to eat 1000kcal of chicken (poultry) instead of beef today, about how much less land would be required to support your feast?

It takes about 150m^2 for a year to produce 1000kcal of beef, and about 5m^2 for a year to produce 1000kcal of chicken, so you would use about 145m^2 less land by eating chicken instead of beef today.

Look again at the graph in Question 12. Why did researchers bother to collect data from the coffee shrubs before adding the nets to treatment plots to exclude birds?

It was important for the researchers to demonstrate that there was no difference between control and treatment plots at the start of the experiment, so they could be sure that any change seen was due to the exclusion of birds and not some other factor such as a difference in shade, water availability, abundance, of beetles, and so on.

Write in the null hypothesis and both sets of predictions.

NPP is not affected by species richness or functional diversity of species. Prediction of hypothesis: NPP will be greater in plots with more species and more functional groups. Prediction of null hypothesis: There will be no difference in NPP based on species richness or number of functional groups.

What is the primary threat in marine environments?

Overexploitation

Propose how the industrial food system contributes to each type of threat in Table 54.2

The industrial food system that produces burgers contributes to threats in these ways: (1) Forests, grasslands, and other types of habitats are destroyed to make way for growing crops such as wheat and for grazing cattle; (2) the overexploitation of other animals, like bison, has made way for cattle; (3) the transport of foods around the world enables the accidental introduction of invasive plants, insects, and other organisms; (4) the pesticides, herbicides, and fertilizers used in food systems are major pollutants; (5) the production and transport of food around the world produces a major amount of greenhouse gases, contributing to climate change.

The abundance of birds and other predators of borer beetles depends on how much natural forest is left within and around the coffee plantations. What is the approximate percentage increase in borer predators per hectare if forest cover is doubled from 15 to 30 percent?

There are about 4 borer predators per hectare at 15 percent cover and about 11 borer predators per hectare at 30 percent cover, a difference of 11/4 x 100 = 2.75 or 275 percent. That is, the abundance of borer predators is about three times higher.

The maps shown here chronicle the loss of old-growth forest (more than 200 years old) that occurred in the United States. In your opinion, under what conditions is it ethical for conservationists who live in the United states to lobby government officials in Brazil, Indonesia, and other tropical countries to slow the rate of loss of old-growth forest?

There is no "correct" answer. One argument is that conservationists could approach officials in tropical countries, including Brazil and Indonesia, and offer to help them learn from the mistakes made in developed nations. it is better to preserve enough forests to maintain biodiversity and keep ecosystem services intact, thus avoiding the expenditures that developed countries face in cleaning up pollution and restoring ecosystems and endangered species.

Explain why the construction of wildlife corridors can help maintain genetic diversity in a fragmented landscape.

Wildlife corridors facilitate the movement of individuals. Corridors allow areas to be recolonized if a species is lost and enable the introduction of new alleles that can counteract genetic drift and inbreeding in small, isolated populations, which tend to reduce genetic diversity.

Describe some of the things you could do to help preserve biodiversity and ecosystem function.

You could consumer fewer resources and produce less waste; drive less and buy local; eat less beef; stop eating foods that threaten species, such as shark fin soup; buy only native plants for your yard and plant more to help create corridors among habitats; resist temptation to release unwanted bait like earthworms or pets like snakes into nature; keep your cat inside; support local and global efforts to preserve natural areas; encourage others to do the same.

Describe how you would determine whether each of the threats in table 54.2 was affecting the orangutans of Borneo.

habitat destruction and fragmentation in Borneo are obvious from the clear cut areas. to assess overexploitation, you could interview local citizens and law enforcement officers on the history of poaching orangutans for the pet trade or for other uses. To assess effects from invasive species, you could use published or local accounts of community structure over time. To asses pollution, you could take direct measurements of soil, water, air, and possibly tissue samples. To asses the effects of climate change, cipitation data, which could affect the species present in the orangutan forest habitat.

Some biologists prefer to focus efforts on preserving endangered species while others prefer to focus on preserving ecosystems. What is your advice to biologists, based on the evidence from this chapter?

no single approach is correct; there are good argments for both efforts. In a case like the orangutans of Borneo, it is not possible to save the orangutans without saving their ecosystem. On the other hand, its much easier to attract money and volunteers to help save a charismatic primate like an orangutan that it is to save a patch of forest. Both types of efforts are needed; their relative importance depends on the circumstances.