1. Biodiversity and Evolution
Chapter 4

2. The American Alligator, worth saving?

3. Core Case Study: Why Should We Care about the American Alligator?
Largest reptile in North America
1930s: Hunters and poachers (sport, bellies, meat)
90% killed off
1967: endangered species
1977: comeback, threatened species

4. Why are alligators important?
Keystone species
Presence in food web –Gar, eggs, small gators
Gator holes- dug out, freshwater, drought
Nesting mounds, used by other animals
Pathways- keep waterways open, hold back changes in swamp
Medicine: blood kills certain types of bacteria, antibodies that destroy drug resistant varieties

5. Four Scientific Principles of Sustainability5

6. 4-1 What Is Biodiversity and Why Is It Important?
Concept 4-1 The biodiversity found in genes, species, ecosystems, and ecosystem processes is vital to sustaining life on earth.

7. What does biodiversity mean to you?

8. Natural Capital: Major Components of the Earth’s Biodiversity

9. Different types of diversity
Species diversity: the number and abundance of species present in different communities
Ecosystem diversity: The variety of ecosystems, aquatic environments found in a place or on earth
Functional diversity: variety in the processes and energy flow in an ecosystem: extra uses of nests, paths of gators
Genetic Diversity: Variety in traits, genetic material found within a certain species

10. Biodiversity Is a Crucial Part of the Earth’s Natural Capital
Vital renewable resources
Variety of food found in all ecosystems
Wood, fibers, energy, medicine
Waste and pest control
Air and water quality (regulation of ecosystem health

11. Questions on 4.1
Q2: What are three ways that the American alligator supports one or more of the four components of biodiversity within its environment?
Q3: What are three examples of how people, in their daily living, intentionally or unintentionally degrade each of these types of biodiversity?
Q4: What are the main differences between Functional and Ecological Diversity? What are the main differences between species and genetic diversity?
Q5: Why is having a lot of biodiversity on earth so beneficial to us?

12. 4-2 Where Do Species Come From?
Concept 4-2A The scientific theory of evolution explains how life on earth changes over time through changes in the genes of populations.
Concept 4-2B 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).

13. What does Evolution mean to you?
Do you think it happens?
Evidence?

14. What do these pictures have in common?

15. Biological Evolution by Natural Selection Explains How Life Changes over Time
Constant struggle for food, resources to survive
Some individuals have advantage over others
Those with tend to have more successful offspring
Charles Darwin
(gathered evidence AND published)
Alfred Russell Wallace

16. What is the tree of life?

17. Six Major Kingdoms of Species as a Result of Natural Selection

18. Prokaryotes
Eukaryotes
Eubacteria
Archaebacteria
Protists
Plants
Fungi
Animals
Cenozoic
First humans
Mesozoic
Extinction of dinosaurs
Plants
colonize land
Paleozoic
500
Origin of
multicellular
organisms
1,000
1,500
Oldest
eukaryotic fossils
2,000
Millions of years ago
Accumulation of
O2 in atmosphere
from photosynthetic
cyanobacterium
2,500
Precambrian
Figure 4.3
Overview of the evolution of life on the earth into six major kingdoms of species as a result of natural selection. For more details, see p. S46 in Supplement 7.
3,000
3,500
Oldest prokaryotic
fossils
4,000
Earth cool enough
for crust to solidify
4,500
Origin of Earth
Fig. 4-3, p. 81

19. Animation: Evolutionary tree of life

20. Animation: Evolutionary tree diagrams

21. The Fossil Record Tells Much of the Story of Evolution
Fossils
Physical evidence of ancient organisms
Bones, casts, tracks…
Some reveal what their internal structures looked like, some their actions
How many species leave fossils?
Have all fossils been discovered?

22. Fossilized Skeleton of an Herbivore that Lived during the Cenozoic Era

23. The Genetic Makeup of a Population Can Change
Populations evolve by becoming genetically different
Genetic variations
First step in biological evolution
Occurs through mutations in reproductive cells
Mutations in other cells can happen , but only reproductive cell mutations are passed on
Sometimes a mutation can result in a new genetic trait that gives it a better chance to survive, sometimes not.

24. Answer
Can a fish species willfully grow limbs and fingers if they are needed to crawl out of the water onto dry land?

25. Individuals in Populations with Beneficial Genetic Traits Can Leave More Offspring
Natural selection: acts on individuals
Second step in biological evolution
Adaptation may lead to differential reproduction
Genetic resistance in bacteria, cockroaches
When environmental conditions change, populations
Adapt
Migrate
Become extinct

26. 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
Figure 4.5
Evolution by natural selection. (a) A population of bacteria is exposed to an antibiotic, which (b) kills all but those possessing a trait that makes them resistant to the drug. (c) The resistant bacteria multiply and eventually (d) replace the nonresistant bacteria.
Stepped Art
Fig. 4-5, p. 83

27. Humans and Natural Selection
Is it still going on? Evidence
Traits that might lead to differential production
Do the number of offspring matter for human adaptation?

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

29. Adaptation through Natural Selection Has Limits
Genetic change must precede change in the environmental conditions
Reproductive capacity
How many
How fast

30. 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

31. Questions on 4.2
Q1) Some people are born with 6 fingers or webbed toes. The above named features are examples of what biological concepts?
Q2) Do the features listed in Q1 have impact on the natural selection process of humans? Explain
Q3) Why does the tree of life have branches?

32. Charles Darwin
There is a grandeur to this view of life (evolution) While this planet has gone cycling on… Endless forms most beautiful and wonderful have been and are being evolved

33. Evolution Timeline Project/Lab

34. Video: Creation vs. evolution

35. Animation: Disruptive selection

36. Animation: Change in moth population

37. Animation: Stabilizing selection

38. 4-3 How Do Geological Processes and Climate Change Affect Evolution?
Concept 4-3 Tectonic plate movements, volcanic eruptions, earthquakes, and climate change have shifted wildlife habitats, wiped out large numbers of species, and created opportunities for the evolution of new species.

39. What drives evolution?

40. What determines the amount of resources?

41. Geologic Processes Affect Natural Selection
Tectonic plates affect evolution and the location of life on earth
Location of continents and oceans
Species physically move, or adapt, or form new species through natural selection
Tectonic actions: Earthquakes, Volcanic eruptions can have profound effects on natural selection
Pollution
Change in ecosystem

42. 225 million years ago 135 million years ago 65 million years ago
Present
Figure 4.6
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 land areas split apart, and also in the rise of new species when isolated land areas combine. Rock and fossil evidence indicates that 200–250 million years ago, all of the earth’s present-day continents were locked together in a supercontinent called Pangaea (top left). About 180 million years ago, Pangaea began splitting apart as the earth’s tectonic plates separated, eventually resulting in today’s locations of the continents (bottom right). Question: How might an area of land splitting apart cause the extinction of a species?
Stepped Art
Fig. 4-6, p. 85

43. Climate Change and Catastrophes Affect Natural Selection
Ice ages followed by warming temperatures
Demise of the giants (sloth, Saber tooth tigers)
Collisions between the earth and large asteroids
New species
Extinction

44. Changes in Ice Coverage in the Northern Hemisphere During the last 18,000 Years

45. Science Focus: Earth Is Just Right for Life to Thrive
Certain temperature range (closeness to sun)
Dependence on water
Rotation on its axis (how fast or slow we spin)
Revolution around the sun (changes in season)
Enough gravitational mass (to hold on to the atmo)

46. Animation: Stanley Miller's experiment

47. Questions on 4.3
Q1) What is the connection between the environment and evolution?
Q2) Will humans evolve to a point where we can survive in space without a spacesuit or any protective device? Why or Why not?
Q3) how does pollution effect evolution?

48. 4-4 How Do Speciation, Extinction, and Human Activities Affect Biodiversity?
Concept 4-4A As environmental conditions change, the balance between formation of new species and extinction of existing species determines the earth’s biodiversity.
Concept 4-4B Human activities can decrease biodiversity by causing the premature extinction of species and by destroying or degrading habitats needed for the development of new species.

49. Evolution Through geographic isolation Through reproductive isolation
Groups of same species become physically isolated
Migration, physical barriers (volcanoes to roads)
Through reproductive isolation
Mutation and change by natural selection occur in isolated geographic populations long enough
New species when interbreeding produces onlysterile offspring

50. Geographic Isolation Can Lead to Reproductive Isolation

51. Speciation Two species arise from one
Environments change for 2 groups of same species
Change progresses to point where breeding produces sterile offspring

52. Animation: Speciation on an archipelago

53. Extinction is Forever Extinction Endemic species
Background 1:5,000,000
Mass >25%
3-5 events in history with mass extinction and low speciation
Endemic species
Specialized
Found in only one location
Particularly vulnerable

54. Golden Toad of Costa Rica, Extinct

55. Genetic engineering, gene splicing Consider
Science Focus: Humans Have Two Ways to Change the Genetic Traits of Populations
Artificial selection
Genetic engineering, gene splicing
Consider
Ethics
Morals
Privacy issues
Harmful effects

56. Genetically Engineered Mice

57. Animation: Transferring genes into plants

58. Video: Cloned pooch

59. Exit questions
Q10 Distinguish between geographic isolation and reproductive isolation.
Q11 Distinguish between artificial selection and genetic engineering (gene splicing)
Q12 Distinguish between background extinction and mass extinction?

60. 4-5 What Is Species Diversity and Why Is It Important?
Concept 4-5 Species diversity is a major component of biodiversity and tends to increase the sustainability of ecosystems.

61. Evolution Through geographic isolation Through reproductive isolation
Groups of same species become physically isolated
Migration, physical barriers (volcanoes to roads)
Through reproductive isolation
Mutation and change by natural selection occur in isolated geographic populations long enough
New species when interbreeding produces onlysterile offspring

62. Species Diversity: Variety, Abundance of Species in a Particular Place
Species richness (diversity in species)
Species evenness (abundance of each species)
Diversity varies with geographical location
Most species-rich communities
Tropical rain forests
Coral reefs
Ocean bottom zone
Large tropical lakes

63. Variations in Species Richness

64. Variation in species evenness
Temperate Forest, African Savannah, Canadian Aspen forest

65. 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
Larger and closer is more species rich
“Island”  isolated region

66. Species-Rich Ecosystems Tend to Be Productive and Sustainable
Species richness seems to increase productivity and stability or sustainability of a location
More diverse ecosystem, more productive, greater biomass
More diverse, more complex web, more resistant to environmental disturbances
Only a hypothesis, more study is needed

67. Questions on 4.5
Q15) Distinguish between species richness and evenness
Q16) Suppose we have 2 national parks close to each other surrounded by development. One is a large park and the other much smaller. Which park is likely to have the highest species richness? Why?
Q17) Explain why species rich ecosystems tend to be productive and sustainable

68. 4-6 What Roles Do Species Play in Ecosystems?
Concept 4-6A Each species plays a specific ecological role called its niche.
Concept 4-6B Any given species may play one or more of five important roles—native, nonnative, indicator, keystone, or foundation roles—in a particular ecosystem.

69. Each Species Plays a Unique Role in Its Ecosystem
Ecological niche
Pattern of living, species way of life and includes everything that affects survival and reproduction
Generalist species (mice, humans, raccoons)
Broad niche
Specialist species
(Tiger salamanders, pandas)
Narrow niche

70. Specialist Species and Generalist Species Niches

71. Case Study: Cockroaches: Nature’s Ultimate Survivors
Generalists
High reproductive rates
10 million annually
Eat almost anything:
Finger nail clippings, electric cords, soap
Live and breed in all but arctic environ
Antennae, knee joints, eyes
Sample food-avoid poison
Good: food for higher order consumers

72. Specialized Feeding Niches of Various Bird Species in a Coastal Wetland
Ruddy turnstone
searches under
shells and pebbles
for small
invertebrates
Dowitcher probes
deeply into mud in
search of snails,
marine worms, and
small crustaceans
Black skimmer
seizes small fish
at water surface
Brown pelican dives
for fish, which it
locates from the air
Herring gull
is a tireless
scavenger
Avocet sweeps bill
through mud and
surface water in search
of small crustaceans,
insects, and seeds
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
Figure 4.13
Specialized feeding niches of various bird species in a coastal wetland. This specialization reduces competition and allows sharing of limited resources.
Fig. 4-13, p. 93

73. Niches Can Be Occupied by Native and Nonnative Species
Nonnative species; invasive, alien, or exotic species
May spread rapidly
Not all are villains (farm- commercial animals)
All disturb the existing ecosystem

74. Killer Bees 1957, Brazil to increase honey production
Instead killed off native bee population
Been migrating North every since
Not terror movie life, but more aggressive and unpredictable

75. Indicator Species Serve as Biological Smoke Alarms
Can monitor environmental quality
Trout (need clean highly oxygenated water)
Birds (fragmentation, pesticides)
Butterflies (fragmentation, species loss)
Frogs (next slide)

76. Case Study: Why Are Amphibians Vanishing? (1)
Habitat loss and fragmentation
Prolonged drought
Pollution
Increase in UV radiation
Parasites (worms causing increase in birth defects)
Viral and fungal diseases
Climate change (2005 and 2008 studies)
Overhunting (Asia and France)
Nonnative predators and competitors

77. Case Study: Why Are Amphibians Vanishing? (2)
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

78. Life Cycle of a Frog Adult frog (3 years) Young frog Sperm
Tadpole develops
into frog
Sexual
reproduction
Tadpole
Figure 4.14
Life cycle of a frog. Populations of various frog species can decline because of the effects of harmful factors at different points in their life cycle. Such factors include habitat loss, drought, pollution, increased ultraviolet radiation, parasitism, disease, overhunting by humans, and nonnative predators and competitors.
Eggs
Fertilized egg
development
Egg hatches
Organ formation
Fig. 4-14, p. 94

79. What is a keystone?

80. Keystone, Foundation Species Determine Structure, Function of Their Ecosystems
Keystone species
Pollinators
Top predator
Loss of keystone species lead to population crashes of other species in ecosystem
Foundation species
Create or enhance their habitats, which benefit others
Elephants (trails)
Beavers (build wetlands)

81. Keystone and foundation species play similar role in building and maintaining an healthy ecosystem

82. Why should we protect sharks?

83. Case Study: Why Should We Protect Sharks?
Keystone species
Eat dead and dying fish in the ocean
Control other populations
Strong immune systems
Wounds do not get infected
Almost never get cancer
Could help humans if we understood their immune system

84. 4.6
Q20) Distinguish between native, invasive, indicator, keystone and foundation species Q21) Distinguish between specialist species and generalist species.

85. Writing assignment Critical thinking questions 7, 8 on pg 98
Use ideas discussed in this or other chapters to fortify your answer to the questions

86. UN Project Questions
Are there regions of your country with large amounts of biodiversity?
What climate conditions/Geologic features have influence natural selection in the major biomes of your country
Indicate some unique indicator, keystone, foundation, invasive and specialist species that live within the borders of your country
Does the people in your country get most of their food from within ?