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Biodiversity Vocabulary 1. Biodiversity: the variety of earth’s species & the genes they carry 2. Species: group of individuals that can mate and have fertile offspring Estimated that there are 10-14 million species Up to ½ of world’s plants & animals in tropical rainforest Most unidentified organisms live in tropical rainforest and oceans 3. Natural capital: stock of natural ecosystems that yields a flow of valuable ecosystem goods or services into the future Importance of Biodiversity 1. At least 40% of the world’s economy and 80% of the needs of the poor are derived from biological resources. 2. The richer the diversity of life, the greater the opportunity for medical discoveries, economic development, and adaptive responses to such new challenges as climate change. Greater species diversity ensures natural sustainability for all life forms Healthy ecosystems can better withstand and recover from a variety of disasters Organisms live by mutually supporting other organisms. Ecosystem Services of Biodiversity 1. Biodiversity underlies all ecosystem services 2. Ecosystem services contribute to making human life both possible and worth living We derive most of our essential food & fibers from animals & plants Biodiversity preserves air and water quality Biodiversity helps to maintain health topsoil Biodiversity decomposes & recycles nutrients Biological Evolution 1. Biological evolution: descent with modification Includes small-scale evolution (changes in gene frequency in a population from one generation to the next) Include large-scale evolution (the descent of different species from a common ancestor over many generations) 2. All life on Earth shares a common ancestor Darwin & Wallace Charles Darwin wrote The Origin of Species in 1858 1. Ideas behind Darwin's theory had been known for decades 2. Geologists and paleontologists: life had been on Earth for a long time life had changed over that time many species had become extinct 3. Darwin showed how all this evidence favored the evolution of species from a common ancestor proposed the mechanism for evolution was natural selection Fitness: those with traits best suited to the environment survive and leave more offspring to the next generation Darwin’s Theory 1. 2. 3. 4. 5. Evolution is gradual; occurs over vast amount of time Variation occurs among individuals within a population Organisms produce more offspring than will survive to reproduce for the next generation Those with the most favorable traits will survive and reproduce (fitness) Darwin DID NOT know about “genetics” and did NOT know about mutations leading to genetic variation Variation within a population Genetic Variability 1. Genetic variability: variety of the genetic make-up of individuals within a population Arise from mutations in DNA (usually can’t detect the change in the physical appearance of the organism) 2. Human blood types: an example Blood Type Type O Type A Susceptible to cholera Resistant to malaria cholera 3. Having natural genetic resistance gives an advantage when confronted with an infectious agent or other environmental factor. Endemic Species and Islands 1. Endemic species: lives no where else in the world evolved from something else. considered at-risk; some are so endangered, researchers count individuals 2. Many live on islands such as Galapagos, Hawaiian, & Madagascar Islands are geographically isolated from the mainland, interbreeding is nearly impossible 3. Endemic species are vulnerable to habitat destruction and habitat loss Geologic Time Scale Extinction The last Trilobites went extinct about 245 mya 1. Extinction: irreversible loss of a species 2. Biological extinction: an entire species is lost 3. Local extinction: species is extinct over a large area, but not globally lost 4. Background extinction: low rate of species disappearance (1-5 species / year for each million species on Earth) 5. Mass extinction: an extinction of a significant proportion of the world's biota in a geologically insignificant period of time evidence of such an event is contained in the fossil record fossil record is most complete from ~542 mya to present. Organisms whose structure includes hard parts (shells & bones) formed beginning about ~ 542 mya Major Mass Extinctions Break up of Pangaea resulted in the greatest mass extinction of time 5 mass extinctions show up in fossil record 450 MYA (Late Ordovician) ~ 85% of marine species became extinct 374 MYA (Late Devonian) ~ 70-80% of marine species became extinct 251 MYA (end of the Permian) ~ 90% of all species became extinct, perhaps 99% of all animals Greatest mass extinction in history 200 MYA (end of the Triassic) most ammonites, half the genera of bivalves, many brachiopods and gastropods, 20% of foraminifera families, 80% of quadrupeds, and all conodonts became extinct 65 MYA (end of the Cretaceous) dinosaur extinction, along with ~2/3 of all species and perhaps 80% of all individual organisms Climate Change and Extinction 1. Polar Bears are threatened by: habitat destruction human encroachment by exposure to persistent organic pollutants greatest threat to them is from the melting of sea ice due to global warming because large areas of open water make it easier for seals to escape 2. Climate change is a threat because species have evolved to live within certain temperature ranges Polar bears do not experience bone loss during 7 months of hibernation (we would lose ⅓ of bone mass) –model for treating osteoporosis? Polar Bears don’t urinate during the several months of hibernation and yet don’t become ill. (We can’t go for more than a few days without eliminating waste or else we die) – model for studying kidney failure Polar bears gain a lot of weight prior to hibernation, but don’t develop Type II diabetes Niche 1. Niche: how a species interacts with its environment Includes: what it eats, how much it eats, when it hunts, when it reproduces 2. What’s the difference between competitive exclusion & coexistence? A. Eating same size seeds so blue out-competes red B. Blue eats a larger seed than red; resource partitioning Genetic Resistance 1. Genetic resistance: ability of 1 or more organisms in a population to tolerate a chemical designed to kill it 2. Many plants contain chemicals that deter herbivores from eating them 3. Milkweed contains cardenolides which is a cardiac arrester When a Monarch caterpillar eats the leaves from the Milkweed, it ingests the cardenolides. This makes the Monarch toxic to many vertebrate predators. Generalist Species 1. Characteristics include: Broad niche can live in many different places Eat a variety of foods Tolerate a wide range of ecological conditions 2. Examples: Flies, cockroaches, raccoons, mice, rates, white tailed deer, humans 3. Not as likely to become endangered, unless overhunted Specialist Species 1. Characteristics Narrow niches Might live in only one type of habitat Use just one resource Tolerate narrow range of environmental conditions 2. Examples: flamingos, Giant panda, Koala Indicator Species Environmental Examples 1. Indicator species: plant or animal that is very sensitive to environmental changes in its ecosystem Affected almost immediately by damage to the ecosystem Give early warming that ecosystem is suffering Damage from air pollution, water pollution, or climate change show first in indicator species 2. Environmental Examples: Euglena thrive in eutrophic water Paramecium are indicators of biological toxins Lichen very sensitive to SO2 in air Amphibians as Indicators 1. Why amphibians are so sensitive: Breathe through their skin, so they are much more directly affected by changes to the chemistry of air & water associated with pollution sensitive to fungi & diseases which can infect them through their skin require aquatic habitats for reproduction directly affected by changing water levels and qualities complex life cycles; often have to move between habitats makes them sensitive to changes in the specific habitats that they need for food and shelter as well as all the places they travel through to get to their preferred habitats Northern Spotted Owl 1. The northern spotted owl lives in old-growth forests. Very territorial & intolerant of habitat disturbance. Prefer old-growth forests with tree canopies that are high & open enough for the owls to fly between & underneath the trees. Each nesting pair needs a large amount of land for hunting & nesting 2. Scientists study the northern potted owl because its presence in an old grow forest means the forest is healthy Keystone and Foundation Species 1. A keystone species is one whose impact on its community or ecosystem is disproportionately large relative to its abundance 2. Foundation species: can cause physical changes that acts as facilitators of biodiversity in the community Keystone Species 1. Keystone species: roles have large effect on the types and abundance of other species in the ecosystem 2. Characteristics: Often limited in numbers Limited numbers makes them more vulnerable to extinction Play critical roles in ecosystems Pollinators: butterflies, hummingbirds, bats Top predators: feed on and help regulate population of other species – wolves, lions, leopards, & sharks 3. Disappearance of the keystone species affects other members of the habitat Remove the wolf, and deer and rabbit population overpopulate, then starve Sea Otters are Keystone Species 1. Sea Otters are one of the few animals that can eat sea urchins. 2. Hunted to near extinction for pelts Treaty passed in 1911 to help protect sea otter Sea urchins eat brown kelp Kelp beds are very important to many fish as a place to have their young If kelp beds disappear, then fish do not have a safe place to spawn Foundation Species 1. Foundation species: can cause physical changes that acts as facilitators of biodiversity in the community 2. Examples: Beavers: Build dams and create ponds; transform forests into wetlands Alligators: Dig deep depressions (gator holes) that hold freshwater during dry season Other aquatic life drawn to gator holes Elephants: push over, break, uproot trees; creates opening in grasslands & wooded areas Corals: produce the reef structure