Chapter 14 Conserving Biodiversity Community and Ecosystem Ecology

Chapter 14 Section 1 The Sixth Mass Extinction Copyright © 2010 Pearson Education, Inc.

14. 1 The Sixth Extinction Terms § Biodiversity – the entire diversity of living organisms in an area § Extinction – the complete loss of a species Endangered Species Act (ESA) § law passed in 1973 to protect and encourage population growth of threatened and endangered species Copyright © 2010 Pearson Education, Inc.

14. 1 The Sixth Extinction Measuring Extinction Rates § History of life on earth

14. 1 The Sixth Extinction Causes of Previous Mass Extinctions § Climate changes § Changes in sea level § Continental drift that changed ocean to land § Asteroid impact Copyright © 2010 Pearson Education, Inc. Figure 14. 2

14. 1 The Sixth Extinction Measuring Extinction Rates § Is the sixth mass extinction event occurring now? § Need to know the background extinction rate § Fossils indicate that average species exists for ~1, 000 years § Estimate of background extinction rate is 0. 0001% per year Copyright © 2010 Pearson Education, Inc.

14. 1 The Sixth Extinction Current rate of extinction § more bird and mammal species have disappeared in the last 150 years § Current Extinction Rate = 0. 01% Copyright © 2010 Pearson Education, Inc. Figure 14. 4

14. 1 The Sixth Extinction Definition of Extinction of modern species § no individuals of a species must have been seen in the wild for 50 years However: § 44 of 68 shallow-water mussel species missing in Tennessee River § 144 of 266 fresh-water fish in Malaysia are missing § 200 of 300 fish from Africa’s Lake Victoria are gone Copyright © 2010 Pearson Education, Inc. Figure 14. 4

14. 1 The Sixth Extinction International Union for the Conservation of Nature (IUCN) § Highly respected organization of scientists, governments and organizations § Predicts that the following are endanger of extinction: § 11% of all plants § 12% of all birds § 24% of all mammals Copyright © 2010 Pearson Education, Inc. Figure 14. 4

14. 1 The Sixth Extinction Four Major Causes of Extinction 1. Loss or degradation of habitat § Most important cause 2. Introduction of non-native species 3. Overexploitation 4. Pollution § Most of these are due to human activities Copyright © 2010 Pearson Education, Inc.

14. 1 The Sixth Extinction 1. Habitat Destruction § As human population increases, pressure on natural areas increases § Species area curve – the number of species that a natural area of a given size can support Copyright © 2010 Pearson Education, Inc.

14. 1 The Sixth Extinction Tropical Rainforest Destruction § ~7722 square miles of So. American rainforest are cut each year. § This rate will reduce rainforest to 10% of original size within 35 years § Will mean extinction of about 50, 000 species Copyright © 2010 Pearson Education, Inc.

14. 1 The Sixth Extinction Habitat destruction not limited to rainforests § Freshwater lakes and streams, grasslands, and temperate forests are also threatened § If worldwide habitat destruction continues at present rate, as many as 25% of all world’s species could become extinct in 50 years § But other threats, such as habitat fragmentation, could push extinction rates even higher Copyright © 2010 Pearson Education, Inc.

14. 1 The Sixth Extinction - Habitat Destruction PLAY Animation—Tropical deforestation and the species

14. 1 The Sixth Extinction Habitat Fragmentation = large natural areas subdivided into smaller areas § Large predators are threatened because they require large home ranges § Human activity usually results in habitat fragmentation Copyright © 2010 Pearson Education, Inc. Figure 14. 5 b

14. 1 The Sixth Extinction - Habitat Fragmentation PLAY Animation—Habitat Destruction and Fragmentation Copyright

14. 1 The Sixth Extinction 2. Introduced Species = non-native species introduced to a new area either purposely or accidentally by human activity § Often destructive because they have not evolved with local species § Brown tree snake, introduced to Guam, caused many local bird species to go extinct § Domestic cats in Wisconsin kill 39 million birds/year § Zebra mussels, accidentally released in the Great Lakes from Europe, are outcompeting native species. § Kudzu, a vine brought from Japan, is now called “the vine that ate the south” Copyright © 2010 Pearson Education, Inc. Figure 14. 5 c

14. 1 The Sixth Extinction 3. Overexploitation = When human use of a natural resource exceeds its reproductive rate. § Can occur if species is highly prized by humans, which can spur illegal hunting. § 3 of 8 species of tigers are extinct, other extremely endangered § Partly due to ‘Traditional Chinese Medicine’ § Can also occur if species competes with humans § Gray wolves almost exterminated by ranchers Copyright © 2010 Pearson Education, Inc.

14. 1 The Sixth Extinction 4. Pollution = The release of poisons, toxins, excess nutrients, and other waste products. § Excess fertilizer runoff leads to eutrophication of waterways § Eutrophication is the excess growth of bacteria that depletes oxygen from the water § Herbicide atrazine is killing amphibians § Carbon dioxide is another atmospheric pollutant, associated with climate change Copyright © 2010 Pearson Education, Inc.

END Chapter 14 Section 1 The Sixth Mass Extinction Copyright © 2010 Pearson Education,

Chapter 14 Section 2 The Consequences of Extinction Copyright © 2010 Pearson Education, Inc.

14. 2 Consequences of Extinction So Why Should We Care If Species Become Extinct? § Extinction is forever § It is unethical to kill entire species § Selfish Reasons § Causing extinction has negative impacts on us too! § Loss of Resources § Environmental instability § Disrupted Energy & Chemical Flows Copyright © 2010 Pearson Education, Inc. Figure 14. 11

14. 2 Consequences of Extinction Loss of Resources § Loss of species can lead to economic impacts for humans § Some biological resources harvested directly include wood (lumber and fuel), shellfish (protein), and algae (gelatin) § Wild species provide biological chemicals (medicines) § Wild species have alleles that are not present in domestic species, which can increase vigor of domesticated species § Wild species can contribute other means of combating pests (biological control) Copyright © 2010 Pearson Education, Inc. Figure 14. 11

14. 2 The Consequences of Extinction – Environmental Instability § Species interact with one another and their environment in complex ways, not just a simple food chain § Communities = all organisms living in a habitat § Niche = the role each species plays in the community Copyright © 2010 Pearson Education, Inc. Food Web Figure 14. 12

14. 2 The Consequences of Extinction – Environmental Instability: Terminology § Mutualism = organism that interact with each other in a mutually beneficial way Copyright © 2010 Pearson Education, Inc. Figure 14. 12

14. 2 The Consequences of Extinction – Mutualism: How Bees Feed the World § Mutualism – relationship in which both species benefit from their interaction § Many examples: § Cleaner fish § Fungal mycorrhizae § Ants and acacia trees § Bees are primary pollinators of many wild plants § Wild bees pollinate 80% of agricultural crops in U. S. § Bee populations are falling due to “colony collapse disorder” § Humans benefit from mutualism, and will lose if bees go extinct Copyright © 2010 Pearson Education, Inc.

14. 2 The Consequences of Extinction – Environmental Instability: Terminology § Predation = survival

14. 2 The Consequences of Extinction – Predation: How Songbirds May Save Forests § Predator – species that survives by eating other species § Songbirds consume many insects § Most insects eaten by songbirds consume plants § Songbirds help to sustain forests § As songbird numbers decline, damage to forests increase Copyright © 2010 Pearson Education, Inc.

14. 2 The Consequences of Extinction – Environmental Instability: Terminology § Competition = when two species both need the same resources (food, shelter, etc), they will be in competition if those resources are limited Copyright © 2010 Pearson Education, Inc. Figure 14. 12

14. 2 The Consequences of Extinction Competition: How a Deliberately Infected Chicken Could Save a Life § A leading cause of food illness in the U. S. is caused by Salmonella enteritidis. § § About 2 million Americans infected each year About 400 die each year as a result of infection Most common source of infection is eggs S. enteritidis contaminates egg when it forms in the hen Copyright © 2010 Pearson Education, Inc.

14. 2 The Consequences of Extinction Competition: How a Deliberately Infected Chicken Could Save a Life § Competitive exclusion is the use of food and space resources by one species, making it impossible for another species to establish § On this principle, chickens are deliberately infected with harmless bacteria § Harmless bacteria establish and prevent S. enteritidis from living in chicken’s gut Copyright © 2010 Pearson Education, Inc.

14. 2 The Consequences of Extinction Competition & Humans § Competition between species can have consequences for humans as well § Mosquitos, snails and tadpoles compete for same resources in ponds § When populations of snails and tadpoles decrease, mosquitoes increase § Potentially serious because mosquitoes can spread malaria, West Nile virus, and yellow fever Copyright © 2010 Pearson Education, Inc.

14. 2 The Consequences of Extinction – Environmental Instability: Terminology § Keystone Species = the activities of a single species can play a dramatic role in the composition of a community Copyright © 2010 Pearson Education, Inc. Figure 14. 12

14. 2 The Consequences of Extinction Keystone Species: Wolves in Yellowstone § Keystone species are key figures in determining the food web of an ecosystem § Wolves were eradicated from Yellowstone Park in 1920 s § With wolves gone, aspen, cottonwood, and willow trees declined § Trees declined due to predation by elk § Trees are crucial for beavers, songbirds, and fish § With reintroduction of wolves, trees and other species rebounded Copyright © 2010 Pearson Education, Inc.

14. 2 The Consequences of Extinction – Ecosystem Energy and Chemical Flows § Ecosystem – includes: § All living organisms in an area § Plus nonbiological environment § Loss of some species can dramatically affect both of these ecosystem properties Copyright © 2010 Pearson Education, Inc. Figure 14. 8

14. 2 The Consequences of Extinction – Disrupted Energy Flows § Energy flow - only a small portion ( ~10%) of the energy in one level of a trophic pyramid can be converted to biomass at the next level § Diversity also affects energy flow, such as in more diverse grasslands, more biomass is produced About 10% of energy taken in by deer is available to mountain lion. About 10% of energy taken in by grass is available to deer. Biomass in mountain lions Biomass in deer population Biomass in grass population Copyright © 2010 Pearson Education, Inc. Figure 14. 8

14. 2 The Consequences of Extinction – Disrupted Chemical Flows § Nutrient cycling – nutrients that pass through a food web rarely leave the system Nitrogen (N 2) Animal protein Plant protein Dead organic matter Nitrate (NO 3–) Decomposers (bacteria and fungi) Nitrite (NO 2–) Copyright © 2010 Pearson Education, Inc. Nitrogen-fixing bacteria in plant root nodules Free-living, nitrogen-fixing bacteria Ammonia (NH 3) Figure 14. 18

14. 2 The Consequences of Extinction – Disrupted Chemical Flows § The soil community has an important role in nutrient cycling § Introduction of non-native earthworms in NE U. S. had dramatic impact on forest plants § Non-native worms changed the soil community Copyright © 2010 Pearson Education, Inc. Figure 14. 19

14. 2 The Consequences of Extinction Psychological Effects § Our experience with nature has strong psychological effects § Instinctive desire to commune with nature is called biophilia § Pets can improve mental well-being § Dental patients viewing landscapes showed a decrease in blood pressure § Hospital patients who could view trees recovered from surgery more quickly § Loss of biodiversity could make human experience less pleasant Copyright © 2010 Pearson Education, Inc.

14. 2 The Consequences of Extinction Replacing Extinction § 5 -10 million years to recover species lost from a mass extinction § Species that replace those lost are different § After mass extinction of dinosaurs, mammals replaced them as dominant large animals § We can not predict what biodiversity will look like after another mass extinction § The mass extinction we are witnessing today will have consequences for thousands of human generations (if humans survive) Copyright © 2010 Pearson Education, Inc.

END Chapter 14 Section 2 The Consequences of Extinction Copyright © 2010 Pearson Education,

Chapter 14 Section 3 Saving Species Copyright © 2010 Pearson Education, Inc.

14. 3 Saving Species - Protecting Habitat § Biodiversity hotspots = less than 2% of the earth’s surface contain up to 50% of the earth’s mammal, bird, reptile, and plant species. These areas are. Caucasus Mediterranean Basin California Floristic Province Caribbean Mesoamerica Polynesia/ Micronesia Choco/ Darien Western Ecuador Central Chile Diversity hot spots Copyright © 2010 Pearson Education, Inc. Tropical Andes Brazil’s Cerrado Brazil’s Atlantic Coast Philippines South Central India. China Burma Polynesia/ Micronesia W. African Forests Tanzania and Kenya Succulent Karoo Western Ghats and Sri Lanka Sundaland Wallacea New Caledonia Madagascar Cape Floristic Province Southwest Australia New Zealand Figure 14. 21

14. 3 Saving Species Protecting Habitat § Converting wild areas to agricultural production is a major cause of habitat destruction. § Altering our consumption patterns can help decrease habitat destruction. § Eating low on the food chain (less meat and dairy) makes a difference. § Reduce consumption of wood and paper § Support conservation organizations § Ultimately, slowing human population growth rate must occur Copyright © 2010 Pearson Education, Inc.

14. 3 Saving Species – Population Size & Environmental Disasters § A large population provides group protection from environmental disaster. § A species with a slow growth rate is at greater risk if its numbers diminish. § The longer a population remains small, the greater its risk. Copyright © 2010 Pearson Education, Inc. Figure 14. 22

14. 3 Saving Species – Population Size & Environmental Disasters § The Heath Hen § § § Lived in New England & numbered in 100, 000 s Declined due to habitat loss to 50 hens Reserve created on Martha’s Vineyard in 1908 Rebounded to 2000 hens by 1915 1916, fire destroyed much of reserve 1917 cold winter brought hungry Goshawks § Then disease from domestic turkeys § 1927, only 14 remained, mostly males § 1932 last survivor seen Copyright © 2010 Pearson Education, Inc. Figure 14. 22

14. 3 Saving Species – Population Size & Environmental Disasters § Lessons from the Heath Hen § Large populations can survive better § EXP: population of 100, 000 can loss 90%, but pop. of 1, 000 can not. § Don’t put all members of species in same reserve § Whooping crane preserves are in Maryland, Wisconsin, Calgary Canada, and Louisiana Copyright © 2010 Pearson Education, Inc. Figure 14. 22

14. 3 Saving Species Conservation Genetics § Loss of genetic variability is a two-fold problem. 1. On individual level, low genetic variability leads to low fitness, and is more likely to express harmful mutant alleles. 2. On population level, loss of genetic variability can lead to extinction due to the low fitness of individuals. Copyright © 2010 Pearson Education, Inc.

14. 3 Saving Species - A Closer Look: Conservation Genetics The Importance of Genetic Variability § When individuals are heterozygotic for many genes, the overall effect is greater fitness. Being heterozygous may confer higher fitness for responding to a changing environment. Homozygote 1: Relatively low fitness (only one type of jacket in wardrobe) Homozygote 2: Relatively low fitness (only one type of jacket in wardrobe) Heterozygote: Relatively high fitness (two types of jackets in wardrobe) Copyright © 2010 Pearson Education, Inc. Figure 14. 23

14. 3 Saving Species - A Closer Look: Conservation Genetics § Heterozygotes can avoid deleterious effects of recessive alleles. Being heterozygous may confer higher fitness by masking deleterious recessive alleles. Homozygote 1: Relatively high fitness (two functional jackets in wardrobe) Homozygote 2: Relatively low fitness (two nonfunctional jackets in wardrobe) Heterozygote: Relatively high fitness (one functional jacket in wardrobe) Copyright © 2010 Pearson Education, Inc. Figure 14. 24

14. 3 Saving Species - A Closer Look: Conservation Genetics § In a small population, individuals are more likely to be related to their mates (inbreeding) § Result can be inbreeding depression, a decline in heterzygotes § Because of this, cheetahs have poor quality sperm and low rate of cub survival § In humans, children of first cousins have lower rates of heterozygosity and higher rates of infant mortality Copyright © 2010 Pearson Education, Inc.

14. 3 Saving Species - A Closer Look: Conservation Genetics The Extinction Vortex § The Consequences of Low Genetic Variability in a Population § A small population can become stuck in a cycle that leads to extinction. Copyright © 2010 Pearson Education, Inc. Figure 14. 26

14. 3 Saving Species - A Closer Look: Conservation Genetics Irish potato famine § a human example of the potentially disastrous effects of low genetic diversity § In 1840 s, Irish potato crop had very low genetic diversity § Fungus that causes potato blight arrived in Ireland; plants rotted in fields § Because of crop failure, nearly 1 million Irish died of starvation and disease Copyright © 2010 Pearson Education, Inc.

14. 4 Protecting Biodiversity Copyright © 2010 Pearson Education, Inc. Table 14. 3

Conservation Organizations NATIONAL WILDLIFE FEDERATION http: //www. nwf. org/ WORLD WILDLIFE FUND http: //www. wwf. org/ NATURE CONSERVANCY http: //www. nature. org/ SIERRA CLUB http: //www. sierraclub. org NATIONAL AUDUBON SOCIETY http: //www. audubon. org/ GREENPEACE http: //www. greenpeace. org/ NATIONAL RESOURCES DEFENSE COUNCIL http: //www. nrdc. org/ ENVIRONMENTAL DEFENSE FUND http: //www. edf. org/ DEFENDERS OF WILDLIFE http: //www. defenders. org/ OCEAN CONSERVANCY http: //www. oceanconservancy. org/ Copyright © 2010 Pearson Education, Inc. Table 14. 3