1. Ecosystems: Diversity and Loss

2. Biodiversity Is a Crucial Part of the Earth’s Natural Capital
Species diversity
Number and variety of species
Genetic diversity
Variety of genes in a population
Ecosystem diversity
Biomes: regions with distinct climates/species
Biodiversity – variety in the earth’s species
Species – set of individuals who can mate and produce fertile offspring
8 million to 100 million species
About 2 million identified
Unidentified species are mostly in rain forests and oceans

3. Biodiversity Is a Crucial Part of the Earth’s Natural Capital
Functional diversity
Variety of processes within ecosystems
Biodiversity is an important part of natural capital
National Capital:
Figure 4.2 Natural capital: The major components of the earth’s biodiversity—one of the planet’s most important renewable resources and a key component of its natural capital (see Figure 1-3, p. 7). Question: Why do you think we should protect the earth’s biodiversity from our actions?

4. 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
Figure 4-4: The major biomes found along the 39th parallel across the United States show a variety of ecosystems. The differences in tree and other plant species reflect changes in climate, mainly differences in average annual precipitation and temperature.
Coastal chaparral
and scrub
Coniferous forest
Desert
Coniferous forest
Prairie grassland
Deciduous forest
Fig. 4-4, p. 81

5. How Does the Earth’s Life Change Over Time?
Theory of evolution: explains how life on earth changes over time through changes in the genes of populations
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)

6. 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
We only have fossils of 1% of all species that lived on earth
Figure 4-5: This fossil shows the mineralized remains of an early ancestor of the present-day horse. It roamed the earth more than 35 million years ago. Note that you can also see fish skeletons on this fossil.

7. Biological Evolution by Natural Selection
Biological evolution – how the earth’s life changes over time through changes in the genetic characteristics of populations
Darwin – On the 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

8. Mutations and Changes in the Genetic Makeup of Populations
Populations evolve by becoming genetically different
Genetic variations
First step in biological evolution
Occurs through mutations in reproductive cells
Mutations – random changes in DNA molecules
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

9. Adaptation through Natural Selection Has Limits
Three common myths:
Fitness is reproductive success, not strength
Organisms do not develop traits out of need or want
There is no grand plan of nature for perfect adaptation
Adaptive genetic traits must precede change in the environmental conditions
A population’s reproductive capacity
Species that reproduce rapidly and in large numbers are better able to adapt

10. How Do New Species Evolve?
Speciation – one species splits into two or more species
Geographic isolation
First step
Physical isolation of populations for a long period
Figure 4.12 Geographic isolation can lead to reproductive isolation, divergence of gene pools, and speciation.

11. How Do New Species Evolve?
Reproductive isolation
Mutations and natural selection in geographically isolated populations
Leads to inability to produce viable offspring when members of two different populations mate

12. All Species Eventually Become Extinct
Extinction
Process in which an entire species ceases to exist
Endemic species
Found only in one area
Particularly vulnerable to extinction
Background extinction
Typical low rate of extinction
Mass extinction
Significant rise above background level

13. Species Diversity Includes Variety and Abundance
Number and variety of species in a given area
Species richness
The number of different species in a given area
Species evenness
Comparative number of individuals of each species present
Diversity varies with geographical location
The most species-rich communities
Tropical rain forests
Coral reefs
Ocean bottom zone
Large tropical lakes

14. Species-Rich Ecosystems Tend to Be Productive and Sustainable
Species richness
Increases productivity and stability or sustainability
Provides insurance against catastrophe
How much species richness do you think is needed?

15. Humans Have Disturbed Much of the Earth’s Land
About 60% of the world’s major terrestrial ecosystems are being degraded
The human ecological footprint is spreading across the globe
Figure 7-18: Natural capital degradation: Projected status of biodiversity in 2018, resulting from ongoing threats of habitat loss and fragmentation, invasions of nonnative species, pollution, climate change, and unsustainable exploitation.

16. Size and Locations of Biomes Can Change
Biomes are not fixed
They change as the climate changes
Human activities are likely to affect biome placement in the future
Figure 7-19: As temperatures rose during the last 18,000 years, huge quantities of ice melted and the global climate changed. This led to shifts in the sizes and locations of several major biomes in eastern North America. Question: Based on these maps, how might you expect the sizes and locations of these biomes to change if the earth’s average atmospheric temperature rises by about 2–5 Co (4–9 Fo) during this century.

17. Core Case Study: Where Have All the Honeybees Gone?
Bees play a key role in pollination
Globally, about one third of the food supply comes from insect- pollinated plants
Currently, agriculture depends heavily on a single species of bee
Suffering from Colony Collapse Disorder
Each year, 30-50% of colonies in Europe and the U.S.
Figure 9-1: European honeybee drawing nectar from a flower.

18. What Role Do Humans Play in the Loss of Species and Ecosystem Services?
Species are becoming extinct 100 to 1,000 times faster than they were before modern humans arrived on the earth
By the end of this century, the extinction rate is expected to be 10,000 times higher than that background rate

19. Extinctions Are Natural but Sometimes They Increase Sharply
Biological extinction
No species member alive
Trophic cascade
Population declines or extinctions among connected species
Mass extinction
Many species in a short amount of time

20. Some Human Activities Hasten Extinctions and Threaten Ecosystem Services
Background extinction rate
1 extinct species / year / 1 million species
Extinction rates have risen recently
Current extinction rate is at least 100 times higher than typical background rate of %

21. Some Human Activities Hasten Extinctions and Threaten Ecosystem Services
Rate of extinction and threats to ecosystem services likely to rise sharply in the next years
Due to harmful human impacts
Biodiversity hotspots
Extinction rates projected to be much higher than average
Biologically diverse environments are being eliminated or fragmented

22. Endangered and Threatened Species Are Ecological Smoke Alarms
Endangered species
So few members that the species could soon become extinct
Threatened species (vulnerable species)
Still enough members to survive, but numbers declining
May soon be endangered
Figure 9-2: Endangered natural capital: These four critically endangered species are threatened with extinction, largely because of human activities. The number below each photo indicates the estimated total number of individuals of that species remaining in the wild, as of 2012.

23. Endangered and Threatened Species Are Ecological Smoke Alarms
Regionally extinct
In areas a species is normally found
Functionally extinct
To the point at which species can no longer play a functional role in the ecosystem
Figure 9-3 Endangered natural capital: Comparison of the percentages of various types of known species that are threatened with extinction hastened by human activities (Concept 9-1). Question: Why do you think so many of the world’s amphibians are threatened with extinction?

24. Why Should We Care about the Rising Rate of Species Extinction?
We should avoid speeding up the extinction of wild species because:
Of the ecosystem and economic services they provide
It can take millions of years for nature to recover from large- scale extinctions
Many people believe that species have a right to exist regardless of their usefulness to us

25. Species Are a Vital Part of the Earth’s Natural Capital
Major reasons to prevent extinctions
Species provide vital ecosystem services
Help keep us alive and support our economies
Many species also contribute economic services
Plants for food, fuel, lumber, and medicine
Ecotourism
Figure 9-5: Natural capital degradation. These endangered orangutans depend on a rapidly disappearing tropical forest habitat. Question: What difference will it make if human activities hasten the extinction of the orangutan?

26. Species Are a Vital Part of the Earth’s Natural Capital
It will take 5-10 million years to regain species biodiversity after this century’s extinctions
Many people believe species have an intrinsic right to exist
How do we decide which species to protect?
Figure 9-6: Natural capital. These plant species are examples of nature’s pharmacy. Once the active ingredients in the plants have been identified, scientists can usually produce them synthetically. The active ingredients in nine of the ten leading prescription drugs originally came from wild organisms.

27. Loss of Habitat Is the Single Greatest Threat to Species: Remember HIPPCO
Habitat destruction, degradation, and fragmentation
Invasive (nonnative) species
Population and resource use growth
Pollution
Climate change
Overexploitation

28. Loss of Habitat Is the Single Greatest Threat to Species
Habitat fragmentation
Large intact habitat divided by roads, crops, and urban development
National parks and nature reserves as habitat islands
Figure 9-8: Natural capital degradation: These maps reveal the reductions in the ranges of four wildlife species, mostly as the result of severe habitat loss and fragmentation and illegal hunting for some of their valuable body parts. Question: Would you support expanding these ranges even though this would reduce the land available for human habitation and farming? Explain.

29. We Have Moved Disruptive Species into Some Ecosystems
Many species introductions are beneficial
Nonnative species may have no natural:
Predators, competitors, parasites, pathogens
Nonnative species can crowd out native species
Invasive species
Figure 9-9: These are some of the estimated 7,100 harmful invasive species that have been deliberately or accidentally introduced into the United States.

30. Case Study: The Kudzu Vine and Kudzu Bugs
Imported from Japan in the 1930s
Help control soil erosion
Very difficult to kill
Could there be benefits of kudzu?
Kudzu bug – imported from Japan
Can kill Kudzu vine
Also kills soybeans
Figure 9-10: Kudzu has grown over this car in the U.S. state of Georgia.

31. Some Accidentally Introduced Species Can Disrupt Ecosystems
Reproduce rapidly and are hard to kill
Greatly depleted Everglades populations of:
Rabbits, foxes, raccoons, opossums, and deer
Argentina fire ant – introduced in the 1930s
Reduced populations of native ants
Painful stings can kill
Pesticide spraying in 1950s and 1960s worsened conditions
Tiny parasitic flies may help control fire ants

32. Other Causes of Species Extinctions
Human population growth and overconsumption
Degrading habitat
Pollution
Bioaccumulation can cause extinctions of species not directly affected by pollution
Climate change
Some species will become extinct, some will spread
Figure 9-13: Bioaccumulation and biomagnification: DDT is a fat-soluble chemical that can accumulate in the fatty tissues of animals. In a food chain or web, the accumulated DDT is biologically magnified in the bodies of animals at each higher trophic level, as it was in the case of a food chain in the U.S. state of New York, illustrated here. (Dots in this figure represent DDT.) Question: How does this story demonstrate the value of pollution prevention?

33. Case Study: Polar Bears and Climate Change
Live only in the Arctic
Arctic ice is melting
Decreasing polar bear habitat
Polar bears must swim farther between ice
Weaker females; less reproduction
Figure 9-14: On floating ice in Svalbard, Norway, a polar bear feeds on its ringed seal prey. Question: Do you think it matters that the polar bear may become extinct during this century primarily because of human activities? Explain.

34. Illegal Killing, Capturing, and Selling of Wild Species Threatens Biodiversity
Poaching and smuggling of animals and plants
Animal parts
Pets
Plants for landscaping and enjoyment
Prevention
Research and education
Figure 9-15: A poacher in South Africa killed this critically endangered northern white rhinoceros for its two horns. This species is now extinct in the wild. With a rhino horn worth up to $300,000 on the Asian black market, thieves have been stealing the horns from museums, antique stores, and even private collections. Question: What would you say if you could talk to the poacher who killed this animal for its horns?

35. Case Study: A Disturbing Message from the Birds
70% of the world’s bird species are declining
Habitat loss and fragmentation of the birds’ breeding habitats
Forests cleared for farms, lumber plantations, roads, and development
Intentional or accidental introduction of nonnative species
These species eat the birds

36. Case Study: A Disturbing Message from the Birds
Exposure to pesticides
Overexploitation
For pets
Birds are indicator species
Respond quickly to environmental changes
Birds perform critical ecosystem and economic services
Extinctions could affect many other species
Figure 9-17: Endangered natural capital: This endangered Attwater’s prairie chicken lives in a wildlife refuge in the U.S. state of Texas.

37. International Treaties and National Laws Help to Protect Species
1975 – Convention on International Trade in Endangered Species (CITES)
Signed by 172 countries
Convention on Biological Diversity (BCD)
Focuses on ecosystems
Ratified by 190 countries (not the U.S.)

38. Case Study: The U.S. Endangered Species Act
Endangered Species Act (ESA) – and later amended in 1982, 1985, and 1988
Identify and protect endangered species in the U.S. and abroad
National Marine Fisheries Service for ocean species
U.S. Fish and Wildlife Service for all others

39. Case Study: The U.S. Endangered Species Act
Forbids federal agencies (except Defense) from funding or authorizing projects that jeopardize endangered or threatened species
In 2012, 1,394 species officially listed
Offer incentives to private property owners to help

40. Case Study: The U.S. Endangered Species Act
Is the ESA a failure?
Species are listed only when in serious danger
Conditions for more than half of listed species are stable or improving
Budget is about 57 cents per U.S. citizen
Figure 9-19: The American bald eagle has been removed from the U.S. endangered species list. Here, an eagle is about to catch a fish in its powerful talons.

41. The Lacey Act of 1900 (United States)
Conservation law in the United States that prohibits trade in wildlife, fish, and plants that have been illegally taken, possessed, transported, or sold.

42. We Can Establish Wildlife Refuges and Other Protected Areas
In 1903, Theodore Roosevelt established the first federal wildlife refuge
Pelican Island, Florida
Wildlife refuges
Most are wetland sanctuaries
More needed for endangered plants
Are not immune from disturbance
Figure 9-20: The Pelican Island National Wildlife Refuge in Florida was America’s first National Wildlife Refuge.

43. Seed Banks, Botanical Gardens, and Wildlife Farms Can Help Protect Species
Preserve genetic material of endangered plants
Botanical gardens and arboreta
Living plants
Farms can raise organisms for commercial sale
Zoos/Aquariums: Techniques for preserving endangered terrestrial species
Egg pulling
Captive breeding
Artificial insemination
Embryo transfer
Use of incubators
Cross-fostering

44. The Precautionary Principle
Act to prevent or reduce harm when preliminary evidence indicates acting is needed
Species are the primary components of biodiversity
Should we focus on the preservation of species or the preservation of ecosystems?