Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Biogeography wikipedia , lookup
River ecosystem wikipedia , lookup
Water pollution wikipedia , lookup
Marine biology wikipedia , lookup
Abyssal plain wikipedia , lookup
Marine pollution wikipedia , lookup
Deep sea community wikipedia , lookup
Marine habitats wikipedia , lookup
Hotspot Ecosystem Research and Man's Impact On European Seas wikipedia , lookup
SUSTAINING THE MILLER/SPOOLMAN EARTH | G. TYLER MILLER | SCOTT E. SPOOLMAN 11e 3 Biodiversity and Evolution © Cengage Learning 2015 3-1 What Is Biodiversity and Why Is It Important? • Crucial part of the earth’s natural capital – Genetic diversity – Species diversity – Ecological diversity – Functional diversity • The earth’s biodiversity – Helps keep us alive and supports our economies © Cengage Learning 2015 Functional Diversity The biological and chemical processes such as energy flow and matter recycling needed for the survival of species, communities, and ecosystems. Genetic Diversity The variety of genetic material within a species or a population. Fig. 3-1 Ecological Diversity The variety of terrestrial and aquatic ecosystems found in an area or on the earth. Species Diversity The number and abundance of species present in different communities. 3-2 Where Do Species Come From? • Biological evolution by natural selection explains how life changes over time – Survival traits become more evident through the process of natural selection – Fossils provide physical evidence – Details of evolution • Still many unanswered questions © Cengage Learning 2015 Evolution by Natural Selection Works through Mutations and Adaptation • Populations evolve by becoming genetically different • Steps in biological evolution – Genes mutate – Individuals are selected – Populations evolve • Better adapted to survive and reproduce under existing environmental conditions © Cengage Learning 2015 (a) (b) Normal bacterium Resistant bacterium Stepped Art Fig. 3-2 (c) (d) Charles Darwin (1809-1882) © Cengage Learning 2015 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 © Cengage Learning 2015 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 © Cengage Learning 2015 Geological Processes, Catastrophes, and Climate Change Affect Natural Selection • Drift of tectonic plates – Continents’ and oceans’ locations shifted – Species migrated, adapted to new environments, and formed new species through natural selection • Tectonic plates’ quick shift → earthquakes • Volcanic eruptions – Along tectonic plates’ boundaries © Cengage Learning 2015 Geological Processes, Catastrophes, and Climate Change • Long-term climate changes – Ice ages followed by warming periods • Collisions between the earth and large asteroids – Extinctions – New species © Cengage Learning 2015 3-3 How Do Speciation, Extinction, and Human Activities Affect Biodiversity? • How do species evolve? – Speciation: one species splits into two or more species – How speciation occurs • Geographical isolation first and then reproductive isolation • Genetic engineering © Cengage Learning 2015 Adapted to cold through heavier fur, short ears, short legs, and short nose. White fur matches snow for camouflage. Arctic Fox Northern population Early fox population Different environmental conditions lead to different selective pressures and evolution into two different species. Spreads northward and southward and separates Gray Fox Southern population Adapted to heat through lightweight fur and long ears, legs, and nose, which give off more heat. Fig. 3-3 Extinction is Forever • Endemic species: found only in one area – Particularly vulnerable • Background extinction rate • Mass extinction: 3-5 over 500 million years • Much biodiversity loss – Due to human activities © Cengage Learning 2015 © Cengage Learning 2015 3-4 What Are Biomes and How Have Human Activities Affected Them? • Climate helps to determine the nature of biomes – Biomes: characterized by climate and dominant vegetation – Climate differences due to: • Average annual precipitation • Average temperature © Cengage Learning 2015 Fig. 3-4 Biomes Are Grouped According to Their Characteristics • Divided into subgroups based on – Average precipitation and temperature, latitude, altitude, and locations and sizes of the nearest bodies of water • Major types – Deserts – Grasslands – Forests – Mountains © Cengage Learning 2015 Cold Arctic tundra Evergreen coniferous forest Temperate desert Temperate deciduous forest Chaparral Hot Wet Cold desert Temperate grassland Tropical desert Tropical rain forest Dry Tropical grassland (savanna) Fig. 3-5 Humans Have Disturbed Most of the Earth’s Lands • Environmental destruction and degradation is increasing in many parts of the world – Preserving natural capital will require • Protecting remaining wild areas from development • Restoring many of the land areas that have been degraded © Cengage Learning 2015 Natural Capital Degradation Major Human Impacts on Terrestrial Ecosystems Deserts Large desert cities Destruction of soil and underground habitat by off-road vehicles Grasslands Conversion to cropland Release of CO2 to atmosphere from burning grassland Forests Clearing for agriculture, livestock grazing, timber, and urban development Conversion of diverse forests to tree plantations Agriculture Damage from offroad vehicles Air pollution blowing in from urban areas and power plants Depletion of groundwater Overgrazing by livestock Land disturbance and pollution from mineral extraction Oil production and off-road vehicles in Pollution of forest arctic tundra streams Fig. 3-6 Mountains Timber and mineral extraction Hydroelectric dams and reservoirs Soil damage from off-road vehicles 3-5 What Are Aquatic Life Zones and How Have Human Activities Affected Them? • Water covers most of the earth and sustains biodiversity – Saltwater covers 71 percent of the planet – Freshwater covers less than 2.2 percent of earth’s surface • Aquatic life zones – Saltwater – Freshwater © Cengage Learning 2015 Ocean hemisphere Fig. 3-7 Land–ocean hemisphere Water Covers Most of the Earth and Sustains Biodiversity • Aquatic life zones – Key factors determining types and numbers of organisms in different layers • Water temperature • Dissolved oxygen content • Food availability • Availability of light and nutrients for photosynthesis © Cengage Learning 2015 Oceans Provide Important Ecosystem and Economic Resources • Reservoirs of diversity in three major life zones – Coastal zone • Less than 10 percent of world’s ocean • Ninety percent of all marine species • High NPP per unit of area – Open sea • Vertical zones: euphotic, bathyal, and abyssal © Cengage Learning 2015 © Cengage Learning 2015 Natural Capital Marine Ecosystems Ecological Services Oxygen supplied through photosynthesis Water purification Food Energy from waves and tides Climate moderation Pharmaceuticals CO2 absorption Harbors and transportation routes Nutrient cycling Reduced storm impact (mangroves, barrier islands, coastal wetlands) Biodiversity: species and habitats Fig. 3-8 Economic Services Recreation and tourism Employment Minerals Open Sea Sea level Euphotic Zone Estuarine Zone Twilight Continental shelf Bathyal Zone Water temperature drops rapidly between the euphotic zone and the abyssal zone in an area called the thermocline. Fig. 3-9 Water temperature (°C) Photosynthesis Depth in meters Abyssal Zone Darkness High tide Coastal Low tide Zone Human Activities Are Disrupting and Degrading Marine Systems • Major threats to marine systems – Coastal development – Overfishing – Runoff of nonpoint source pollution – Point source pollution – Habitat destruction © Cengage Learning 2015 Natural Capital Degradation Major Human Impacts on Marine Ecosystems and Coral Reefs Marine Ecosystems Half of coastal wetlands lost to agriculture and urban development Over one-fifth of mangrove forests lost to agriculture, aquaculture, and development Beaches eroding due to development and rising sea levels Fig. 3-10 Coral Reefs Ocean bottom habitats degraded by dredging and trawler fishing Ocean warming Rising ocean acidity Soil erosion Algae growth from fertilizer runoff Bleaching Rising sea levels Increased UV exposure At least 20% of coral reefs severely damaged and 25–33% more threatened Damage from anchors and from fishing and diving Why Are Freshwater Ecosystems Important? • Standing (lentic) freshwater bodies – Lakes – Ponds – Inland wetlands • Flowing (lotic) freshwater systems – Streams – Rivers © Cengage Learning 2015 Natural Capital Freshwater Systems Ecological Services Economic Services Climate moderation Food Nutrient cycling Drinking water Waste treatment Irrigation water Flood control Groundwater recharge Habitats for many species Genetic resources and biodiversity Scientific information Fig. 3-11 Hydroelectricity Transportation corridors Recreation Employment Painted turtle Blue-winged teal Green frog Muskrat Pond snail Littoral zone Plankton Diving beetle Northern pike Yellow perch Bloodworms Why Are Freshwater Ecosystems Important? • Lake classification by nutrient content and primary productivity – Oligotrophic lakes • Low levels of nutrients and low NPP – Eutrophic lakes • High levels of nutrients and high NPP – Hypereutrophic lakes – Mesotrophic lakes © Cengage Learning 2015 Why Are Freshwater Ecosystems Important? • • • • Surface water Runoff Watershed (drainage basin) Aquatic life zones – Source zone – Transition zone – Floodplain zone © Cengage Learning 2015 Rain and snow Lake Glacier Rapids Waterfall Tributary Flood plain Oxbow lake Salt marsh Delta Deposited sediment Ocean Source Zone Transition Zone Floodplain Zone Stepped Art Fig. 3-13 Water Sediment Human Activities Are Disrupting and Degrading Freshwater Systems • Dams and canals – Fragment the world’s largest rivers • Flood control levees and dikes – Disconnect rivers from their floodplains and destroy aquatic habitat • Pollutants from cities and farms – Impact water quality • Drained wetlands © Cengage Learning 2015