1. CHAPTER 4: Biodiversity and Evolution

2. Core Case Study: Why Should We Protect Sharks?
400 known species
6 human deaths/year from shark attacks
79-97 million sharks killed every year
Fins – used in Asia for soups and cure-alls
Organs, meat, hides also valuable
32% shark species threatened with extinction
Current news? Not good…
Keystone species in the ocean
Cancer resistant species!

3. Threatened Sharks!
Figure 4.1: The threatened whale shark (left), which feeds on plankton, is the largest fish in the ocean. The endangered scalloped hammerhead shark (right) is swimming in waters near the Galapagos Islands, Ecuador. They are known for eating stingrays, which are related to sharks.
Fig. 4-1, p. 80

4. What is Biodiversity? Species diversity Genetic diversity
Ecosystem diversity
Biomes: regions with distinct climates/species
Functional diversity – energy flow and nutrient cycling
Biodiversity is an important part of natural capital

5. Functional Diversity The biological and chemical processes such as energy flow and matter recycling needed for the survival of species, communities, and ecosystems.
Ecological Diversity The variety of terrestrial and aquatic ecosystems found in an area or on the earth.
Solar energy
Chemical nutrients (carbon dioxide, oxygen, nitrogen, minerals)
Heat
Heat
Heat
Decomposers (bacteria, fungi)
Producers (plants)
Consumers (plant eaters, meat eaters)
Heat
Heat
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?
Genetic Diversity The variety of genetic material within a species or a population.
Species Diversity The number and abundance of species present in different communities.
Fig. 4-2, p. 82

6. Biodiversity Is a Crucial Part of the Earth’s Natural Capital
Species: set of individuals who can mate and produce fertile offspring
Estimate: 8 million to 100 million species on earth
10-14 million is the “best guess”
Insects make up most of the world’s known species
1.9 million identified species
Unidentified are mostly in rain forests and oceans

7. Classifying Homo Sapiens
Figure 2 This diagram illustrates the taxonomic classification of the latest human species, Homo sapiens sapiens.
Supplement 5, Fig. 2, p. S19

8. Science Focus: Have You Thanked the Insects Today?
Bad rep: sting us, bite us, spread disease, eat our food, invade plants
Pollination: lets flowering plants reproduce sexually
Free pest control: insects eat other insects
We need insects more than they need us!

9. Major Biomes: large regions with distinct climates and certain species (especially vegetation)
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.
Fig. 4-5, p. 84

10. Individuals Matter: Edward O. Wilson- A Champion of Biodiversity
Loved bugs as a kid; Specialized in ants
Widened scope to earth’s biodiversity
Encyclopedia of Life – Harvard
Theory of island biogeography
How species diversity on islands is affected by the size and location of the islands
First to use “biodiversity” in a scientific paper
Won two Pulitzers for his nonfiction books
His website

11. Edward O. Wilson
Figure 4.B: Edward O. Wilson.
Fig. 4-B, p. 85

12. 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

13. 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

14. Biological Evolution by Natural Selection Explains How Life Changes over Time
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
Huge body of evidence

15. 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

16. Evolution by Natural Selection Works through Mutations and Adaptations
POPULATIONS EVOLVE by becoming genetically different
INDIVIDUALS DO NOT EVOLVE!!
Genetic variations
First step in biological evolution
Occurs through mutations in reproductive cells
Mutations: random changes in DNA molecules

17. 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, causing a shift in the traits expressed in a population
Simulation
Genetic resistance: ability of one or more members of a population to resist a chemical designed to kill it

18. A group of bacteria, including genetically resistant ones, are
exposed to an antibiotic
Normal bacterium
Resistant bacterium
Eventually the resistant strain
replaces the strain affected by
the antibiotic
The genetically resistant bacteria
start multiplying
Most of the normal bacteria die
Stepped Art
Fig. 4-7, p. 87

19. Case Study: How Did Humans Become Such a Powerful Species?
Strong opposable thumbs
Walk upright
Complex brain

20. Adaptation through Natural Selection Has Limits
Adaptive genetic traits must precede change in the environmental conditions
Individuals cannot adapt their own genetics when they environment changes!
Reproductive capacity
Species that reproduce rapidly and in large numbers are better able to adapt
Gene mutations and differential reproduction occur faster

21. Three Common Myths about Evolution through Natural Selection
“Survival of the fittest” is not “survival of the strongest”
Organisms do not develop traits out of need or want
No grand plan of nature for perfect adaptation

22. 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 – can separate and isolate species, can cause speciation
Volcanic eruptions – can destroy habitats and reduce species populations

23. 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

24. 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

25. 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

26. 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

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

28. Northern Hemisphere Ice coverage
18,000 years before present
Northern Hemisphere Ice coverage
Modern day
(August)
Legend
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)
Continental ice
Sea ice
Land above sea level
Fig. 4-9, p. 89

29. Science Focus: Earth Is Just Right for Life to Thrive
Temperature range: supports life
Orbit size: moderate temperatures
Liquid water: necessary for life
Rotation speed: sun doesn’t overheat surface
Size: gravity keeps atmosphere

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

31. Geographic Isolation Can Lead to Reproductive Isolation
Adapted to cold through heavier fur, short ears, short legs, and short nose. White fur matches snow for camouflage.
Arctic Fox
Northern population
Different environmental conditions lead to different selective pressures and evolution into two different species.
Spreads northward and southward and separates
Early fox population
Gray Fox
Figure 4.10: Geographic isolation can lead to reproductive isolation, divergence of gene pools, and speciation.
Southern population
Adapted to heat through lightweight fur and long ears, legs, and nose, which give off more heat.
Fig. 4-10, p. 91

32. Extinction is Forever Extinction Endemic species
Biological extinction – gone from the planet
Local extinction - lost of a species over a large area
Endemic species
Found only in one area (islands, rainforests, etc.)
Particularly vulnerable to extinction
Background extinction: typical low rate of extinction
Mass extinction: 3-5 over 500 million years

33. Golden Toad of Costa Rica, Extinct
Used to live in the cloud forest – went extinct in 1989 when the forest dried up
Figure 4.11: This male golden toad lived in Costa Rica’s high-altitude Monteverde Cloud Forest Reserve. The species became extinct in 1989 apparently because its habitat dried up.
Fig. 4-11, p. 92

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

35. Species Diversity: Variety, Abundance of Species in a Particular Place
Species diversity: the number and variety of species
Species richness:
The number of different species in a given area
Species evenness:
Comparative number of individuals

36. Variations in Species Richness and Species Evenness
Figure 4.12: These two types of ecosystems vary greatly in species richness. An example of high species richness is a coral reef (left), with a large number of different species. On the other hand, this grove of aspen trees in Alberta, Canada (right) has a small number of different species, or low species richness.
High species richness
High species evenness
Low species richness
Low species evenness
Fig. 4-12, p. 93

37. 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

38. Global Map of Plant Biodiversity
Figure 6 Global map of plant biodiversity.
Supplement 8, Fig. 6, p. S36

39. Science Focus: Species Richness on Islands
Species equilibrium model, theory of island biogeography
Rate of new species immigrating should balance with the rate of species extinction
Island size and distance from the mainland need to be considered
Helps to predict needs of isolated wildlife areas, such as national parks

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

41. 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

42. 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

43. 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

44. Case Study: Cockroaches: Nature’s Ultimate Survivors
3500 species , been around for 350 million years
Generalists
Eat almost anything
Live in almost any climate
High reproductive rates
1 Asian cockroach leads to 10 million new cockroaches

45. Species Can Play Five Major Roles within Ecosystems
Native species: normally live and thrive in a specific ecosystem
Nonnative species: aka invasive/alien/exotic species
Can be deliberately or accidentally introduced
Food crops, flowers, livestock – all beneficial nonnatives
Some compete with and reduce a community’s native species (killer bees)
Can spread rapidly if there are no predators/diseases to keep their population in check

46. Species Can Play Five Major Roles within Ecosystems
Indicator species
Provide early warning of damage to an ecosystem because they respond quickly to environmental changes
Example: fish, birds , butterflies, & amphibians
Keystone species
Species whose roles have large effect on the types and abundance of other species in a ecosystem
Usually exist in small numbers and are susceptible to extinction
Examples: pollinators and predators

47. Species Can Play Five Major Roles within Ecosystems
Foundation species
Species that play a major role in shaping their communities by creating and enhancing their habitats in way that benefit other species
Elephants – push over trees
Beavers – build dams
Some bats and birds – spread fruit plants with droppings
Difference between this and keystone?
Foundation species create habitats
Keystone can do this plus maintain the ecosystem

48. Case Study: Why Are Amphibians Vanishing?
Habitat loss and fragmentation
Prolonged drought
Pollution
Increase in UV radiation
Parasites
Viral and fungal diseases
Climate change
Overhunting
Nonnative predators and competitors

49. Case Study: Why Are Amphibians Vanishing?
Importance of amphibians
Sensitive biological indicators of environmental changes
Adult amphibians
Important ecological roles in biological communities
Genetic storehouse of
pharmaceutical products
waiting to be discovered

50. Case Study: Why Should We Care about the American Alligator?
Largest reptile in North America
1930s: Hunters and poachers
Importance of gator holes and nesting mounds: a keystone species
1967: endangered species
1977: comeback, threatened
species

51. 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.

52. Three Big Ideas
Each species plays a specific ecological role (ecological niche) in the ecosystem where it is found.