>> today on ththe "earth focus"- biodiversrsity. ththe world's s species arere disappppearing at a surprising rate, and the consequences for human health are enormous. cocoming up on "earth focus." >> bioiodiversity as a way to describe the sheer variety of life on earth. lifefe -- on land, air and sea.

the sheer diversity of life on earth is a testament to the majesty, beauty, and wonder that is the natural world. millions of species of plants, animals, and microorganisms and the environment that habit are part of a creature interrelalatd system. they depenend on what other forr survival. human beings are part of this intricate web of life. biodiversity is also a source of cultural and spiritual wealth, an essential part of human tradition and inspiration. the earth's natural systetems provide a range of services vital to our survival. species for other our food, livelihood, medicines, as well as to purify our air and water.

oceans provide food and help regulate the climate. forest regulate water supplies and provide fuel. but all too often, we take these services for granted. today, h human actions are pushg nanatural systems to the limit, and this, scientists say, can undermine not only the quality of life, but humanan survivall ititself. we probably don''t know the names of about 95% of everything liliving in the ocean. most of the life in the ocean has nenever been studied by scientists. >> there may be 10000 million microbial specieies. there may be a billion. nobody has any idea about that whatsoever. >> most of the world's biological diversity is found in the world's rain forests of the coral reefs and new species

continue to be identified. deep ocean environment in particular often -- offer tantalizing prospects for the discovery of a known forms of life. no one knows how many species exist on earth. scientists have named at catalog just over 1 million species. what we do know for certain is that we are losing species at an unprecedented rate. losing species before we even knewew they shared our planet. >> at the variety of life is going down quite rapidly. >> i its going to change ththe nature of our culture, our cities, and how we go about our daily lives. >> in earth's history, there have been five mass extinction events. the last of which occurred 65 million years ago. >> there was a mass extinction from an enormous media or,

asteroid thahahit the earth t tt cocost tremendous debris to go p into the atmosphere and cooled the planet for a long time. >> half of all species went extinct, including the dinosaurs. the rate of species loss today is on par with that event, and is by far and away the highest rate of species loss since humans have been around. their rate of species loss today is probably at least 100 times that which occurred before humans were around. for many groups of species, the rate is near to 1000. mass extinction is caused by one species -- man. >> we are on pace to lose 50% of species b by 2100, l largely duo habitat loss anand climate chan. >> the major danger is habitatt destruction.

each s species has very speciail habitat requirements. once you destroy those, you destroy the species. >> we are cutting down our rain forests atat an alarming rate. we are overfisishing in thee ocean, we are consuming natural resources at an unsustainable rate. the earth's surface has already been altered by humans. three-quarters will be altered in the next 30 years. pollution from farms, pesticides, and fertilizer runoff as causing dead zones in lakes and sees. 80 percent of the world's fisheries are depleted, over exploited, or in a state of collapse. one-third of all coral species are at risk of extinction. we are definitely a big past on earth. destroying some

ecosystems. >> climate change will make an already bad situation worse and could become a factor most responsible for species' extinction in the next century. based pcss 30% % of land- are e at risk from extinctioiony century's end. nobody knows what that t is going to mean. clearly, a tremendous problems with food, tremendouss problems with water, tremendous death of species and all kinds. heat waves everywhere. the roleg challenge is of carbon dioxide, which both heats up the notion that makes it more acidic. two degrees fahrenheit or 1 degrees centigrade causes something called coral bleaching. and prolonged, can lead to massive amounts of coral dedeh.

the second thing carbon dioxide does is it dissolves in the ocean and makes the ocean more acidic. a more acidic pollution, it's much harder for organisms to secretee their skeletons, so coral has a harder time doing what is supposed to do. >> you can quickly realize how the warming of the plplanet and changing the way the water cycle of the plan works are two consequences of f greenhouse gas emissions that cause climate change could affect the ability of species to live. cold-blooded species have to maintain their body temperatures by staying out of ththe heat. if it is getting warmer, that forces them to move. right n now, we are living throh a mass migration of f species toward the poles of the planet, those that can get out the heat. >> the most important thing to understand aboutut biodiversitys not that individual organisms are important, but they persist that isological web interactivee.

the loss of one species leads to ramifications on others. >> scientists and some not -- scientists now say the higher extinction we are experiencing could reduce nature's ability to provide food, clean water, and a stable envnvironment. >> whahat we really need to do s wait that as a species and understand that this plan that actually works not just as a physical system, but as a linked biological a and physical syste rerecognize is absbsolutely fundamental to our existence. >> biological diversity plays an important role in madison. plants were no further healing properties for thousands of years. , therly as 2600 b.c.

mesopotamia's used oil from cedar and cypress trees and the opium poppy to treat alien -- to treat ailments. ancient chinese, tibetan and indian medicines all prescribed drugs that are mostly plant- based. >> if you are on the medication, rticularlyly for cancer or infectious disease, it's a good chance the medicines that are saving your life would not exist or not for nature. >> most of the medicines we take are made in laboratories today. , their designion and discovery has is directly relied verery heavily on molecules' w we have discoveredn plants, animals, and microorganisms. >> this includes drugs like stanton's which are widely used all over the world. insulin is a natural product. >> there is something that's used against herpes that comes

from a marine sponge. there is also a cancer -- an anti-cancer agent that comes from sea squirts. >> the rosy periwinkle, a plant found in nascar, revolutionized the treatment for hodgkin's lymphoma. was found inant the marquetry of and design -- amazon rain forest. morphine was isolated from the opium poppy. aspirin was synthesized from compounds found the part of the white willow and from the plant, but this week. >> today, a f first-line treatmt we h have for malaria, one of te world's biggest killers, is that on a plant from china is currently our best hope for a controrolling this tremendous disease. >> if you look k at all the new drugs approved by the u.s. fofod and drug administration between

1981 and 2006, almost two-thirds of those would have had their origins in nature, not in our lab. what's more interesting is that oftentimes, nature gives us molelele'ss t that may not maket fully through fda trials, but teach us a tremendous amount about how our bodies work in helping disease. inre is a drug used patients and used on coronary artery stance. these are little mesh tubes that get put into the blood vesessels and supply the heart with oxygen. they are put in after a heart attack and the artery gets clogged. the drug comes from a soil microbes on easterer island.

it's becoming incredibly useful. it turns out t that its value to medicine is far greater as a drug. we were able to understand a part of how a our cells know when to divide because of this drug. there is a protein in n every cell calalled the molecucular targets and we only discovered this protein because we found this molecule in nature. this protein is the gatekeeper fofowhen the cell knows when to divide. sometimes because nature works through trial and error as it tries to figure out how to deal with all the challenges that come up, it can come up with solutions or molecules that no rational person mightht conceive of. those sorts of innovations can be tremendously valuable to madison.

from acillin was derived bolt to become a widely used antibiotic to treat diseases like syphilis and staff infections. another antibiotic was developed from a fungus found in a soil samample in the jungles f borneo. >> we found them from snakes have given us the ability to derstand h how to frereeze specific neurological cells and in some cases, provide therapeutic agents. . >> particularly the stuff that lives glued down to the bottom of the ocean is a rich source of potential medicinin because those organisms cannot moved.d. that meaeans have to defend themselves by being nasty to eat. the ththings that t make them ny to each are often in very small amounts very helpful to us. one of the bestxamples i in terms of medicines are t the coe

snails. there are about 700 species. each of them has betweween 10202 hundrered specialized p poisonsy usused to capapture and k kill r play. -- katrine kill their prey. onlyly a handful have been lookd at for medicine. >> these chemicals but from common sale -- from: snails are being investigated. there are clinical trials for new drugs for epilepsy, a clinical trial for drugs that will protect nerve cells during strokes, heart swelled during heart attacks, anand one of thee chemicals is on the market now. it is the most important painkiller that has been discovered in essentially since morphine in the early 1800's. it is s 1000 times moree potent than morphine. it is based on one of these: stale poisons, just one.

it is being used for patients who no longeger respond to a opiates. snailseople believe conone may have more medicines important t to humans than any otherr organisms on the planete withth global warming,g, if f we destroying "-- if we are destroyingng coral reefs, we may lose the most valuable pharmacopoeia on the planet. when we lose specieses, they are gogone forever. we cannot buy them back, nor can we discover thesese potential secrets that could be lifesaving. if people understood that better, i think they would behave very differently. >> today, amphibians are one of the most threatened species on earth. nearly one-third are in d danger of going e extinct. >> they're very sensitive t to changeges in their environment. poisons, of climate change,

habitat destruction. if you have never held an end to be in your hand, you know that they feel moist and clammy. that is because they breathe through their skin. in order to do that, the skin is very thin and moist. it is used in of fact as a lung to some extent. many of them breathes through their skin exclusively. there are some animals that only breeze through their skin. they also take up water through their skin. as they do this, because they do not have a very effective barrier with the outside theyeynment, they cannot -- can't absorbable lot of the toxins and chemicals into their bodies very readily. there are many well-documented studies that show various chemicals which are comommerciay applied as herbicides s or pesticides commercially in the context of agriculture as well as in people managing their own homes and gardens, many of them

are chemically very similar to certain basic hormones in humans and other animals. they are so close chemically to the naturally occurring hormone is that they actualllly disrupt our norormal and the cururrent balance in our body. hence the term in the crown destructor. was untilious one recently among the most widely used commercial use herbicides in the world. is known to feminize males. chromosomeproducing elite male frogs, they would devevelop abnormamal testes. in some cases, the testes will have follicles and produce eggs. with theireres behavior, physiology and so forth. frogs are very diverse and our species that specialize in different ways, whether it is their breeding biology or

coloration. scientists have discovered particular features that have evolved in one group or another have interesting phararmacological benefits for humans. in some cases, they are or were being developed as potential drugs. >> researchers are looking at how compounds from and to be and -- including those with hiv aids. at a time when antibiotic resistance is becoming more widespread, scientists say amphibians bailed the key to new antibiotics and ways of overcocoming antibiotic resistance. >> there were two species of frog in australia known as the gastric brooding frog. they have one of the more bizarre reproductive biology is. the female frogs lay eggs externally, as most frogs do.

the male would fertilize them extra early as is typical, but the female would turn around and swallow the fertilized eggs into her stomach, where they would stay for several weeks, developing and ultimately should give birth orally. the frogs would litererally popd out t of their mouth. if most people or frogs take someththing into their stomachs, it is s digested. how come these eggs stay in n te stomach for r weeks at a time, embryos s that little f frog les fofor weeks s at a time and note digested? as it turned out, studies in the 1980's began by australian biologist found out the tadpoles were secreting a substance which deactivated the stomach lining. it was not producing digigestive enzymes. it was i inhibiting the e stomah

activity and enabling it to serve as a uterus. there are some unfortunate syndromes in humans called ulcer's involving the lining of the stomachch caused by over sesecretion of digestive enzyme these frogs were steady in the sensnse that hopefully it might provovide some means of controlling human ststomach ulcecers. the tragedy comes in that the species were only discovered in the 1980's. within a few years, they went extinct in nature. ultimately, those animals diedd out and the species w was lost forever. they canannot be studied and longer. arctitic ice is t turning ththe survivalal of the p polar wiwith a loss of the polar bear may c come the loss of potential medicines for diseases like osteoporosis, kidney failure, and diabetes. . essentiallyrs are

in mobile as every hibernating bebear is fofor five-seven mont yet they do not get osteoporosis. their bones donon't ththin. there are the only mammal that does not get osteoporosis with prolonged immobility. if we were in mobilele for five months, if we were hospitalized or paralyzed, we would lose one- third of our bone mass. mobility, thehe balance shifts t to losing bone. osteoporosis. this is an enormous public health problem in the united states and the rest of the world. 70,000 people bought in this country every year, costing the u.s. economy $18 billion a year. one-third of women over 65, post menopausal women, will have a fracture not caused by injury, but caused by osteoporosis.

polar bears andnd other hibernating bears have substances in their blood that prevent that from getting osteoporososis. another thing a aut polarr bears -- they don't urinate for five- seven months or longer. yet they don't get toxic.c. if we don't get ridid of our urinary waste for a few days, we are dead. endndis no treatment for ststage renal disease or renal failure. the only thing you can do for someone whose kidneys not unching is to essentially -- his kidney is not functioning is to essentially give them a kidney transnsplant. there i is no medication they cn take. 26 million amerericans have chronic renanal disease. that number is increasing with untreated hypertensnsion and obesesity-related diabetes. massive priorcome

to hibernating because they need to live off their body fafat. theyey're eating it seal blubber to get that that, yet they do not get diabetic. when we become obese, we become diabetic. this is an epidemic disease not only in the united states, but around the world. there are half a billion people obese around the world. a greater proportion of women ththan men. 295 million women and 210 billion mend. 210 million men. of ththe city has dououbled in e last years in united statates ad itit leads to type 2 diabetes, n enormous public health problele it kills a a quarter of a millin people in this country every year and costs the economomy $90 billion. we havave no idea how polar beas prevent b becoming diabetic, evn

thouough they a are massivelely. we to understand that. we have to sttudy them in the wild. they do nott hibernate in zoos r in laboratories. polar bears have secrets to teach us. if people understood those connections better, i think they would have a much greater value to biodiversity, to ecosystems and individual species. >> we both have to understand what science is telling us. we are losing this diversity of life. that loss is directly inflfluencing our ability to led healthier lives. >> if we expropriate the whole earth and try to take off, , we are the lords of creation -- wee are not. we are one of millions of animals. to ththink of itt as planet the oceanan. we have to livive within our

means. living within ouour means applis to ecology just as much as it applies to budgets. >> it dodoes require i immediate actition, because the longer we wait, the more sesevere things will be.e. >> we are a social primatetes. as a social climate, we spend a lot of time paying attention to each other. i think it is likike a bununch f baboons' sitting arounund groom each other while t the environmental law and snsneaks ththat. all of the sum, we should have been doing something about it. only sometimes make changes when they feel they have no other chohoice. is parartly the role of physysicians to helplp them reae they have no other choice because of our health and our lives depend on it.

reyes: welcome to the show. illegal gold mining has created a pocket of poisonous destruction in the amazon forest 10 times the size of manhattan. the police have been crackingg down on the small-time miners, destroying their crude camps and sometimes putting them i in jai. but the amazon is a big place, and authorities say they can't keep up.p.llegal minining has helped make peru one of the world's lalargest exporters of gold. the miners claim they have no other work and must support their families. correspondent gerry hadden traveled to peru to