1.Core Case Study: “Have you thanked your insects today?”- Explain why insects are significant. Many of the earth’s plant species depend upon insects to pollinate them. Carnivorous insects, such as the praying mantis, control the ‘pest’ insect population. 2.What percentage of the species on this planet consists of insects? Animals? Plants? 53% are insects; 20% are other animals; 18% are plants.
3.Give three examples of how we benefit from microbes.
Soil bacteria convert nitrogen gas into usable forms for plants; they decompose wastes into nutrients we use; they help produce various foods such as bread, cheese, wine, beer, and tofu. 4.What percentage of the biomass on this planet accounts for microbes? 90% of earth’s living mass.
5.Define the four spheres of the earth.
The atmosphere is the thin membrane of air around the planet. The troposphere is the air layer about 11 miles above sea level. The stratosphere lies above the troposphere between 11-30 miles; it filters out the sun’s harmful radiation. The hydrosphere consists of earth’s water, found in liquid water, ice, and water vapor. The lithosphere is the crust and upper mantle of the earth’s soil. It contains nonrenewable fossil fuels, minerals, and soil, and renewable soil chemicals needed for plant life. The biosphere includes most of the hydrosphere, parts of the lower atmosphere and upper lithosphere. All parts of the biosphere are interconnected. 6.Describe the three interconnected factors that life depends on. The flow of high-quality energy; the cycling of matter or nutrients; gravity. 7.Describe what happens to all of the solar radiation that reaches the earth. Solar energy flowing through the biosphere warms the atmosphere, evaporates and recycles water, generates winds, and supports photosynthetic life. 8.Is the greenhouse effect a positive or negative issue for life on earth? Explain why. It is a positive effect because without it, the earth would be...