1. BIODIVERSITY & EVOLUTION
CHAPTER 4
BIODIVERSITY
& EVOLUTION

2. Three Big Ideas
Populations evolve when genes mutate and give some individuals genetic traits that enhance their abilities to survive and to produce offspring with these traits (natural selection).
Human activities are decreasing the earth’s vital biodiversity by causing the extinction of species and by disrupting habitats needed for the development of new species.
Each species plays a specific ecological role (ecological niche) in the ecosystem where it is found.

3. Biodiversity Is a Crucial Part of the Earth’s Natural Capital
Species: set of individuals who can mate and produce fertile offspring
8 million to 100 million species
1.9 million identified
Unidentified are mostly in rain forests and oceans
Biodiversity Is a Crucial Part of the Earth’s Natural Capital

4. Classifying Homo Sapiens
Figure 2 This diagram illustrates the taxonomic classification of the latest human species, Homo sapiens sapiens.

5. Natural Capital: Major Components of the Earth’s Biodiversity
Figure 4.2: Natural capital.
This diagram illustrates the major components of the earth’s biodiversity—one of the earth’s most important renewable resources and a key component of the planet’s natural capital (see Figure 1-4, p. 9). See an animation based on this figure at CengageNOW. Question: What role do you play in such degradation?

6. Coastal mountain ranges Mississippi River Valley
Major Biomes
Denver
Baltimore
San Francisco
Las Vegas
St. Louis
Coastal mountain ranges
Sierra Nevada
Great American Desert
Rocky Mountains
Great Plains
Mississippi River Valley
Appalachian Mountains
Coastal chaparral
and scrub
Coniferous forest
Desert
Prairie grassland
Deciduous forest
Figure 4.5: The major biomes found along the 39th parallel across the United States are shown in this diagram. The differences in tree and other plant species reflect changes in climate, mainly differences in average annual precipitation and temperature.

7. Biological Evolution by Natural Selection Explains How Life Changes over Time
Fossils
Physical evidence of ancient organisms
Reveal what their external structures looked like
Fossil record: entire body of fossil evidence
Only have fossils of 1% of all species that lived on earth

8. Fossilized Skeleton of an Herbivore that Lived during the Cenozoic Era
Figure 4.6: This fossilized skeleton is the mineralized remains of an herbivore that lived during the Cenozoic era from 26 to 66 million years ago.
Fig. 4-6, p. 86

9. Biological evolution: how earth’s life changes over time through changes in the genetic characteristics of populations
Darwin: Origin of Species
Natural selection: individuals with certain traits are more likely to survive and reproduce under a certain set of environmental conditions
Verification: huge body of evidence
Biological Evolution by Natural Selection Explains How Life Changes over Time

10. Evolution of Life on Earth
Figure 1 This diagram provides an overview of the evolution of life on the earth into six major kingdoms of species as a result of natural selection.
Supplement 5, Fig. 2, p. S18

11. Evolution by Natural Selection Works through Mutations and Adaptations
Populations evolve by becoming genetically different from other populations
Genetic variations
First step in biological evolution
Occurs through mutations in reproductive cells
Mutations: random changes in DNA molecules
Evolution by Natural Selection Works through Mutations and Adaptations

12. Evolution by Natural Selection Works through Mutations and Adaptations
Natural selection: acts on individuals
Second step in biological evolution
Adaptation may lead to differential reproduction
Genetic resistance: ability of one or more members of a population to resist a chemical designed to kill it

13. Evolution by Natural Selection
Fig. 4-7, p. 87
(a)
A group of
bacteria,
including genetically resistant ones,
are exposed to
an antibiotic
(b)
Most of the normal bacteria die
(c)
The genetically resistant bacteria start multiplying
(d)
Eventually the resistant strain replaces all or most of the strain affected by the antibiotic
Normal bacterium
Resistant bacterium
Figure 4.7: Evolution by natural selection. (a) A population of bacteria is exposed to an antibiotic, which (b) kills all individuals except those possessing a trait that makes them resistant to the drug. (c) The resistant bacteria multiply and eventually (d) replace all or most of the nonresistant bacteria.

14. Adaptation through Natural Selection Has Limits
Adaptive genetic traits must precede change in the environmental conditions
Reproductive capacity
Species that reproduce rapidly and in large numbers are better able to adapt
“Survival of the fittest” is not necessarily “survival of the strongest”
Organisms do not develop traits out of need or want
No grand plan of nature for perfect adaptation
Adaptation through Natural Selection Has Limits

15. Geologic Processes Affect Natural Selection
Tectonic plates affect evolution and the location of life on earth
Locations of continents and oceans have shifted
Species physically move, or adapt, or form new species through natural selection
Earthquakes
Volcanic eruptions

16. Movement of the Earth’s Continents over Millions of Years
Figure 4.8: Over millions of years, the earth’s continents have moved very slowly on several gigantic tectonic plates. This process plays a role in the extinction of species, as continental areas split apart, and also in the rise of new species when isolated island areas such as the Hawaiian Islands and the Galapagos Islands are created. Rock and fossil evidence indicates that 200–250 million years ago, all of the earth’s present-day continents were connected in a supercontinent called Pangaea (top left). About 180 million years ago, Pangaea began splitting apart as the earth’s tectonic plates moved, eventually resulting in the present-day locations of the continents (bottom right). Question: How might an area of land splitting apart cause the extinction of a species?
Fig. 4-8, p. 89

17. 225 million years ago
Figure 4.8: Over millions of years, the earth’s continents have moved very slowly on several gigantic tectonic plates. This process plays a role in the extinction of species, as continental areas split apart, and also in the rise of new species when isolated island areas such as the Hawaiian Islands and the Galapagos Islands are created. Rock and fossil evidence indicates that 200–250 million years ago, all of the earth’s present-day continents were connected in a supercontinent called Pangaea (top left). About 180 million years ago, Pangaea began splitting apart as the earth’s tectonic plates moved, eventually resulting in the present-day locations of the continents (bottom right). Question: How might an area of land splitting apart cause the extinction of a species?
Fig. 4-8, p. 89

18. 135 million years ago
Figure 4.8: Over millions of years, the earth’s continents have moved very slowly on several gigantic tectonic plates. This process plays a role in the extinction of species, as continental areas split apart, and also in the rise of new species when isolated island areas such as the Hawaiian Islands and the Galapagos Islands are created. Rock and fossil evidence indicates that 200–250 million years ago, all of the earth’s present-day continents were connected in a supercontinent called Pangaea (top left). About 180 million years ago, Pangaea began splitting apart as the earth’s tectonic plates moved, eventually resulting in the present-day locations of the continents (bottom right). Question: How might an area of land splitting apart cause the extinction of a species?
Fig. 4-8, p. 89

19. 65 million years ago
Figure 4.8: Over millions of years, the earth’s continents have moved very slowly on several gigantic tectonic plates. This process plays a role in the extinction of species, as continental areas split apart, and also in the rise of new species when isolated island areas such as the Hawaiian Islands and the Galapagos Islands are created. Rock and fossil evidence indicates that 200–250 million years ago, all of the earth’s present-day continents were connected in a supercontinent called Pangaea (top left). About 180 million years ago, Pangaea began splitting apart as the earth’s tectonic plates moved, eventually resulting in the present-day locations of the continents (bottom right). Question: How might an area of land splitting apart cause the extinction of a species?
Fig. 4-8, p. 89

20. Present
Figure 4.8: Over millions of years, the earth’s continents have moved very slowly on several gigantic tectonic plates. This process plays a role in the extinction of species, as continental areas split apart, and also in the rise of new species when isolated island areas such as the Hawaiian Islands and the Galapagos Islands are created. Rock and fossil evidence indicates that 200–250 million years ago, all of the earth’s present-day continents were connected in a supercontinent called Pangaea (top left). About 180 million years ago, Pangaea began splitting apart as the earth’s tectonic plates moved, eventually resulting in the present-day locations of the continents (bottom right). Question: How might an area of land splitting apart cause the extinction of a species?
Fig. 4-8, p. 89

21. 225 million years ago 135 million years ago 65 million years ago
Present
Stepped Art
Fig. 4-8, p. 89

22. Climate Change and Catastrophes Affect Natural Selection
Ice ages followed by warming temperatures
Collisions between the earth and large asteroids
New species
Extinctions

23. Changes in Ice Coverage in the Northern Hemisphere During the last 18,000 Years
Figure 4.9: These maps of the northern hemisphere show the large-scale changes in glacial ice coverage during the past 18,000 years. Other smaller changes in glacial ice on mountain ranges such as the European Alps are not shown. Question: What are two characteristics of an animal and two characteristics of a plant that natural selection would have favored as these ice sheets (left) advanced? (Data from the National Oceanic and Atmospheric Administration)
Fig. 4-9, p. 89

24. How Do New Species Evolve?
Speciation: one species splits into two or more species
Reproductive isolation: mutations and natural selection in isolated populations lead to inability to produce viable offspring when members of two different populations mate
Geographic isolation: one mechanism of reproductive isolation; happens first; requires physical isolation of populations for a long period
How Do New Species Evolve?

25. Geographic Isolation Can Lead to Reproductive Isolation
Figure 4.10: Geographic isolation can lead to reproductive isolation, divergence of gene pools, and speciation.
Fig. 4-10, p. 91

26. Extinction is Forever Extinction Biological extinction
Local extinction
Endemic species
Found only in one area
Particularly vulnerable
Background extinction: ongoing; low rate of extinction
Mass extinction: rapid and devastating; 3-5 times over 500 million years

27. Changing the Genetic Traits of Populations
Artificial selection
Use selective breeding/crossbreeding
Genetic engineering, gene splicing
Consider
Ethics
Morals
Privacy issues
Harmful effects

28. Artificial Selection
Figure 4.C: Artificial selection involves the crossbreeding of species that are close to one another genetically. In this example, similar fruits are being crossbred.
Fig. 4-C, p. 92

29. Genetically Engineered Mice
Figure 4.D: These mice are an example of genetic engineering. The 6-month-old mouse on the left is normal; the same-age mouse on the right had a human growth hormone gene inserted into its cells. Mice with this gene grow two to three times faster than, and twice as large as, mice without it. Question: How do you think the creation of such species might change the process of evolution by natural selection?
Fig. 4-D, p. 92

30. Species Diversity: Variety, Abundance of Species in a Particular Place
Species diversity is a combination of:
1. Species richness:
The number of different species in a given area
2. Species evenness:
Comparative number of individuals

31. Species Diversity: Variety, Abundance of Species in a Particular Place
Diversity varies with geographical location
The most species-rich communities
Tropical rain forests
Coral reefs
Ocean bottom zone
Large tropical lakes

32. Species-Rich Ecosystems Tend to Be Productive and Sustainable
Species richness seems to increase productivity and stability or sustainability, and provide insurance against catastrophe
How much species richness is needed is debatable

33. Each Species Plays a Unique Role in Its Ecosystem
Ecological niche, niche
Pattern of living: everything that affects survival and reproduction
Water, space, sunlight, food, temperatures
Generalist species
Broad niche: wide range of tolerance
Specialist species
Narrow niche: narrow range of tolerance

34. Specialist Species and Generalist Species Niches
Figure 4.13: Specialist species such as the giant panda have a narrow niche (left) and generalist species such as the raccoon have a broad niche (right).
Fig. 4-13, p. 95

35. Specialized Feeding Niches of Various Bird Species
in a Coastal Wetland
Herring gull is a tireless scavenger
Brown pelican dives for fish, which it locates from the air
Ruddy turnstone searches under shells and pebbles for small invertebrates
Avocet sweeps bill through mud and surface water in search of small crustaceans, insects, and seeds
Dowitcher probes deeply into mud in search of snails, marine worms, and small crustaceans
Black skimmer seizes small fish at water surface
Figure 4.14: This diagram illustrates the specialized feeding niches of various bird species in a coastal wetland. This specialization reduces competition and allows sharing of limited resources.
Flamingo feeds on minute organisms
in mud
Scaup and other diving ducks feed on mollusks, crustaceans, and aquatic vegetation
Louisiana heron wades into water to seize small fish
Oystercatcher feeds on clams, mussels, and other shellfish into which it pries
its narrow beak
Knot (sandpiper) picks up worms and small crustaceans left by receding tide
Piping plover feeds on insects and tiny crustaceans on sandy beaches
Fig. 4-14, p. 96

36. Species Can Play Five Major Roles within Ecosystems
Native species
Nonnative species
Indicator species
Keystone species
Foundation species

37. Indicator Species Serve as Biological Smoke Alarms
Provide early warning of damage to a community
Can monitor environmental quality
Trout
Birds
Butterflies
Frogs

38. Keystone Species Play Critical Roles in Their Ecosystems
Keystone species: roles have a large effect on the types and abundances of other species
Pollinators
Top predators

39. Foundation Species Help to Form the Bases of Ecosystems
Create or enhance their habitats, which benefit others
Elephants
Beavers