Do you drink coffee? A lot of people do—coffee is a major tropical crop, valued at over $100 billion per year. The most popular species of coffee, Coffea arabica, originated in Africa and is now planted extensively in Central and South America. The pest called the coffee berry borer beetle (Hypothenemus hampeii) moved along with the coffee and is a major problem for coffee farmers, sometimes destroying half of the coffee crop in mature plantations. 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.

Do you drink coffee? A lot of people do—coffee is a major tropical crop, valued at over $100 billion per year. The most popular species of coffee, Coffea arabica, originated in Africa and is now planted extensively in Central and South America. The pest called the coffee berry borer beetle (Hypothenemus hampeii) moved along with the coffee and is a major problem for coffee farmers, sometimes destroying half of the coffee crop in mature plantations. 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.

Scientists around the world are collaborating to understand how deforestation, climate change, and natural processes will interact to affect one of the most productive and biodiverse ecosystems on Earth.

Many studies have raised the concern that positive feedback loops among numerous variables in the Amazon will cause an ecosystem tipping point—a rapid and irreversible transition from forest to grassland. Use the model in Question 14 as a tool to summarize a possible sequence of effects that could cause a transition from forest to grassland.

Will increasing atmospheric levels of CO₂ make you sneeze as well as itch?

Scientists studying the effects of rising CO₂ levels have looked at ragweed, whose pollen is the primary allergen for fall hay fever. They grew ragweed in three levels of CO₂: a pre-industrial concentration of 280 ppm, a year 2000 level of 370 ppm, and a projected level of 600 ppm. They found that pollen production increased by 131% and 320% in the plants exposed to the recent and projected CO₂ levels, respectively.

What was the hypothesis of this experiment?

Do the results support the hypothesis?

Given what you know about climate change, what other variables would you like to test, and what other measurements would you like to take?

Scientists around the world are collaborating to understand how deforestation, climate change, and natural processes will interact to affect one of the most productive and biodiverse ecosystems on Earth. Journalists must be concise when reporting science news. Why might journalists and the public struggle to understand and discuss ecosystems ecology and global warming?

Most scientific experts agree that climate change is already occurring and has potentially catastrophic consequences for all of life on Earth. The Paris Agreement of 2015 represented a global consensus on the need to reduce greenhouse gas emissions. However, in 2017 the United States announced its intention to withdraw from the Agreement in 2020. Go online to research and summarize the main agreements reached in this historic global climate accord and the U.S. government's reasons for withdrawing. What roles do you think scientists, politicians, and citizens will need to play to cut emissions and limit global warming?

In 1954, workers at Michigan State University began spraying the elm trees on campus annually with DDT to kill disease-carrying bark beetles. In the spring of 1955, large numbers of dead robins were found on the campus. Observers thought perhaps the robins died after eating earthworms contaminated by DDT the previous spring. Suggest how scientists could have investigated the scientific validity of this idea.

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

What is a biodiversity “hotspot”?

a. an area where an all-taxon survey is under way

b. a habitat with high NPP

c. an area with high species richness and high threat to those species