Nudibranch Ecological (Ecosystem) Diversity 1
Domain Archaea 古菌域 Domain Bacteria 細菌域 域 界 Domain Eukarya Threatened Sharks 2
Why Should We Protect Sharks? 400 known species 6 deaths per year from shark attacks 79 97 million sharks killed every year Fins Organs, meat, hides ( 皮 ) Fear 32% shark species threatened with extinction Keystone species Cancer resistant Biodiversity Is a Crucial ( 關鍵 ) Part of the Earth s Natural Capital Species: set of individuals who can mate and produce fertile offspring 8 million to 100 million species 1.9 million identified Unidentified are mostly in rain forests and oceans Two Species: Columbine Lily and Great Egret Classifying Homo Sapiens Biodiversity Is a Crucial ( 關鍵 ) Part of the Earth s Natural Capital Species diversity Heat Functional Diversity The biological and chemical processes such as energy flow and matter recycling needed for the survival of species, communities, and ecosystems. Chemical nutrients (carbon dioxide, oxygen, nitrogen, minerals) Heat Heat Solar energy Ecological Diversity The variety of terrestrial and aquatic ecosystems found in an area or on the earth. Genetic diversity Decomposers (bacteria, fungi) Producers (plants) Ecosystem diversity Biomes: regions with distinct climates/species Heat Consumers (plant eaters, meat eaters) Heat Functional diversity Genetic Diversity The variety of genetic material within a Species Diversity The number and abundance of species present in different communities. Fig. 4-2, p. 82 3
Genetic Diversity Major Biomes San Francisco Las Vegas Denver St. Louis Baltimore Coastal mountain ranges Sierra Nevada Great American Desert Rocky Mountains Great Plains Mississippi Appalachian River Valley Mountains Genetic diversity among individuals in a population of a species of Caribbean snail Coastal chaparral and scrub Coniferous forest Desert Coniferous forest Prairie grassland Deciduous forest Have You Thanked the Insects Today? Importance of Insects Bad rep ( 代表 ): 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 Individuals Matter: Edward O. Wilson: A Champion of Biodiversity Edward O. Wilson Loved bugs as a kid Specialized in ants Widened scope to earth s biodiversity Theory of island biogeography First to use biodiversity in a scientific paper 4
Biological Evolution by Natural Selection Explains How Life Changes over Time Fossils Physical evidence of ancient organisms Reveal what their external structures looked like Only have fossils of 1% of all species that lived on earth Biological Evolution by Natural Selection Explains How Life Changes over Time Evolution of Life on Earth 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 Evolution by Natural Selection Works through Mutations and Adaptations Populations evolve by becoming genetically different 域 Genetic variations First step in biological evolution Occurs through mutations in reproductive cells Mutations: random changes in DNA molecules 界 5
(a) A group of bacteria, including genetically resistant ones, are exposed to an antibiotic Evolution by Natural Selection (b) Most of the normal bacteria die (c) The genetically resistant bacteria start multiplying (d) Eventually the resistant strain replaces all or most of the strain affected by the antibiotic Case Study: How Did Humans Become Such a Powerful Species? Strong opposable thumbs Walk upright Complex brain Normal bacterium Resistant bacterium 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 Three Common Myths about Evolution through Natural Selection 1. Survival of the fittest is not survival of the strongest 2. Organisms do not develop traits out of need or want 3. No grand plan of nature for perfect adaptation 225 million years ago 135 million years ago Fig. 4-8, p. 89 Fig. 4-8, p. 89 6
65 million years ago Present Fig. 4-8, p. 89 Fig. 4-8, p. 89 Climate Change and Catastrophes ( 災難 ) Affect Natural Selection Changes in Ice Coverage in the Northern Hemisphere During the last 18,000 Years Ice ages followed by warming temperatures Collisions ( 碰撞 ) between the earth and large asteroids New species Extinctions Fig. 4-9, p. 89 How Do New Species Evolve? Temperature range: supports life Orbit ( 軌跡 ) size: moderate temperatures Liquid water: necessary for life Rotation speed: sun doesn t overheat surface Size: gravity keeps atmosphere Speciation: one species splits into two or more species Geographic isolation: happens first; physical isolation of populations for a long period Reproductive isolation: mutations and natural selection in geographically isolated populations lead to inability to produce viable offspring when members of two different populations mate 7
Geographic Isolation Can Lead to Reproductive Isolation Extinction is Forever Extinction Biological extinction Local extinction Endemic species Found only in one area Particularly vulnerable Background extinction: typical low rate of extinction Mass extinction: 3 5 over 500 million years Golden Toad of Costa Rica, Extinct Changing the Genetic Traits of Populations Artificial selection Use selective breeding/crossbreeding Genetic engineering, gene splicing Consider Ethics Morals Privacy issues Harmful effects Artificial Selection Genetically Engineered Mice normal a human growth hormone gene inserted into its cells 8
Species Diversity: Variety, Abundance of Species in a Particular Place Species diversity Species Diversity: Variety, Abundance of Species in a Particular Place Diversity varies with geographical location Species richness: The number of different species in a given area Species evenness: Comparative number of individuals The most species rich communities Tropical rain forests Coral reefs Ocean bottom zone Large tropical lakes Variations in Species Richness and Species Evenness Global Map of Plant Biodiversity Species Rich Ecosystems Tend to Be Productive and Sustainable Species richness seems to increase productivity and stability or sustainability, and provide insurance against catastrophe 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 9
Specialist Species and Generalist Species Niches Specialized Feeding Niches of Various Bird Species in a Coastal Wetland Black skimmer seizes small fish at water surface Brown pelican dives for fish, which it locates from the air Avocet sweeps bill through mud and surface water in search of small crustaceans, insects, and seeds Herring gull is a Ruddy tireless turnstone scavenger searches Dowitcher probes under shells deeply into mud in and pebbles search of snails, for small marine worms, and invertebrates small crustaceans 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 Cockroaches: Nature s Ultimate Survivors Cockroach 3500 species Generalists Eat almost anything Live in almost any climate High reproductive rates Species Can Play Five Major Roles within Ecosystems Native species Nonnative species Indicator species Keystone species Indicator Species Serve as Biological Smoke Alarms Indicator species Provide early warning of damage to a community Can monitor environmental quality Trout Birds Butterflies Frogs Foundation species 10
Why Are Amphibians Vanishing? 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 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 Red Eyed Tree Frog and Poison Dart Frog Keystone Species Play Critical Roles in Their Ecosystems Keystone species: roles have a large effect on the types and abundances of other species Pollinators Top predators Why Should We Care about the American Alligator ( 短吻鱷 )? American Alligator Largest reptile in North America 1930s: Hunters and poachers ( 盜獵者 ) Importance of gator (alligator) holes and nesting mounds ( 丘 ) : a keystone species 1967: endangered species 1977: comeback, threatened species 11
Foundation Species Help to Form the Bases of Ecosystems Create or enhance their habitats, which benefit others Elephants Beavers Three Big Ideas 1. 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). 2. 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. Three Big Ideas 3. Each species plays a specific ecological role (ecological niche) in the ecosystem where it is found. 12