MILLER/SPOOLMAN, SUSTAINING THE ENVIRONMENT, 12E
CHAPTER SUMMARY
CHAPTER 3
3-1 What is biodiversity and why is it important?
Biodiversity involves several levels including genetic, species, ecological, and functional diversity. It is a vital
renewable resource that keeps us alive as long as we live off of the biological natural income it provides.
CONCEPT 3-1 The biodiversity found in the earth’s genes, species, ecosystems, and ecosystem processes is vital to
sustaining life on the earth.
1. What is biodiversity, and why is it vital to sustaining life on Earth.
2. Summarize the four main facets of biodiversity.
3-2 Where do species come from?
The theory of evolution states that all species descend from earlier, ancestral species. Microevolution describes
small genetic changes that occur in a population. Macroevolution describes long-term, large-scale evolutionary
changes when new species form and others disappear. CONCEPT 3-2 According to the scientific theory of
evolution through natural selection, populations evolve when genes mutate and give some individuals genetic traits
that enhance their abilities to survive and to produce offspring with these traits.
3. Briefly describe the theory of evolution, being sure to include the roles played by variation within the
gene pool and natural selection, extinction, and speciation. Summarize and address three common
misconceptions about evolution.
4. What are fossils, and what information can they provide in terms of how life developed on Earth?
3-3 How do speciation, extinction, and human activities affect biodiversity?
For natural selection to evolve, a population must have genetic variability, must have heritable traits, and individuals
with the trait must reflect differential reproduction. Natural selection can lead to development of an entirely new
species; in speciation, two species arise from one. Species may become extinct through background extinction when
local environmental conditions change and through mass extinctions when 25–75% of the species is lost.
CONCEPT 3-3 As environmental conditions change, the balance between formation of new species and extinction
of existing species determines the earth’s biodiversity.
5. Define speciation. Explain how geographic isolation and reproductive isolation can result in speciation.
6. Distinguish between background extinction and mass extinction.
7. Explain why we should be concerned about extinction of species.
3-4 What are biomes and how have human activities affected them?
Terrestrial parts of the earth are called biomes. Biomes are influenced by climate, latitude, and altitude. CONCEPT
3-4A Differences in average annual precipitation and temperature lead to the formation of tropical, temperate, and
cold deserts, grasslands, and forests and largely determine their locations. CONCEPT 3-4B In many areas, human
activities are impairing ecological and economic services provided by the earth’s deserts, grasslands, forests, and
mountains.
8. Describe how climate affects the distribution of plant life on Earth. Compare the climate in deserts,
grasslands, forest, and mountains. Summarize the interactions of altitude, latitude, and biome type.
9. Describe two different human activities that are negatively impacting terrestrial biomes.
3-5 What are aquatic life zones and how have human activities affected them?
Freshwater life zones and ocean/marine life zones are the two types of aquatic life zones on the earth; different types
of organisms, plant and animal, evolve in these aquatic zones, according to land, water, and human interactions and
conditions. CONCEPT 3-5A Saltwater and freshwater aquatic life zones cover almost three-fourths of the earth’s
surface, with oceans dominating the planet. CONCEPT 3-5B The key factors determining biodiversity in aquatic
systems are temperature, dissolved oxygen content, availability of food, and availability of light and nutrients
necessary for photosynthesis. CONCEPT 3-5C Human activities threaten aquatic biodiversity and disrupt
ecological and economic services provided by saltwater and freshwater systems.
10. Evaluate the significance of the ecological contributions of the oceans. Distinguish between coastal
zones and open sea. List and compare the four principal zones of an ocean.
11. Distinguish between coastal and inland wetlands. Describe the ecological functions performed by
wetlands. Describe environmental problems associated with coastal and inland wetlands.
12. List and compare the four zones of a lake. Distinguish between oligotrophic and eutrophic lakes.
Describe stratification and a turnover in a lake.
MILLER/SPOOLMAN, SUSTAINING THE ENVIRONMENT, 12E
CHAPTER SUMMARY
CHAPTER 3
13. Name three different human activities that are currently threatening aquatic life zones.