Life in the World's Oceans [TTC Video]
20 February 2018, 09:03
Course No 1725 | M4V, AVC, 640x360 | AAC, 160 kbps, 2 Ch | 30x30 mins | + PDF Guidebook | 3.44GB
For thousands of centuries, humans lived near the ocean, wandered right up to its edge, and turned back to the relative safety of the known land. Even when we invented ships and the very bravest among us sailed out, our fears and imaginations took over. What creatures could be living in the unknowable darkness, the bottomless depths? Giant worms, microorganisms that eat metal, faceless fish, giant sea spiders? Marine life is even more otherworldly and fantastical than we ever imagined, and Life in the World’s Oceans brings you face to face with these exciting creatures. From the phytoplankton that can only float at the whim of wind and currents to the gray whale that migrates 16,000 kilometers each year, you will be amazed at the variety of life in the seas and what we have only recently learned about its biology, evolution, life cycles, and adaptations.
The Great Courses has partnered with the Smithsonian to produce a vivid exploration of life in this fascinating space—the environment that accounts for 99 percent of Earth’s habitable space. With curatorial expertise, content development, and stunning still and video imagery provided by Smithsonian’s National Museum of Natural History, you’ll understand our planet’s ocean environment and the life it supports as you never have before.
Working in close consultation with Don Wilson, curator Emeritus from the Smithsonian Natural History Museum, Professor Sean K. Todd of the College of the Atlantic—and one of the world’s leading marine biologists—developed 30 fascinating lectures that take you on a journey from the beginning of life on Earth four billion years ago to the environmental factors and international treaties and protocols that affect our oceans today. With an easygoing manner and an infectious passion for his topic, Professor Todd shares the latest research from the field's most fascinating areas of study, including marine-mammal intelligence and communication, bioluminescence, exploration of the ocean floor, as well as the Smithsonian’s own cutting-edge research work around the world, including the Great Barrier Reef.
Phytoplankton: Carrying the Weight of Ocean Life—and Us
Professor Todd starts your ocean journey at the very beginning, with the wonders of water and a fascinating look at the specific properties that make this unique molecule the essential ingredient for life. You’ll learn how life itself was ignited in this environment, eventually evolving into the phytoplankton that help keep us alive today, providing about 50 percent of all atmospheric oxygen. This phytoplankton—primarily free-floating, photosynthetic, and microscopic algae; and protists and prokaryotes—is the base of almost every marine food web. In fact, the largest animal ever known to have existed on earth, the 200-ton blue whale, sustains itself throughout an 80- to 90-year lifespan by eating only krill, which itself feeds directly on phytoplankton. With each blue whale requiring four tons of krill per day, it’s easy to see the critical link between a healthy phytoplankton population and whale viability.
Professor Todd also explains how research with new technology has recently reversed more than one common “truth” about marine life. DNA analysis has revealed new relationships between lifeforms and resulted in major taxonomic changes. And high-tech submersibles have allowed biologists to explore the deepest ocean floor, revealing a pathway to life in the absence of sunlight. Only recently have scientists learned that bacteria and other organisms use the hot, metal-rich fluids released by hydrothermal vents to turn chemical energy into food. That energy then fuels species of snails, shrimp, giant tube worms, and others that have evolved to thrive in these aphotic ecosystems.
And if snails, shrimp, and giant tube worms are not enough to peak your interest, the unforgettably dramatic images provided through this course give you access into the depths of the oceans, grant you up-close-and-personal encounters with charming marine mammals, and allow insights into the exhibits of Smithsonian’s National Museum of Natural History that you wouldn’t get without being there—from the fossils of red alga to the giant skeleton of a Basilosaurus in the Sant Ocean Hall.
Those Charismatic Marine Mammals
Life in the World’s Oceans provides a fascinating view into the complex lives of marine mammals, enhanced by stunning visual resources from the Smithsonian. Professor Todd shares his own exciting research and field experience with marine mammals to help respond to the most commonly asked questions about their intelligence.
In this course, you’ll learn that:
- Some marine mammals use tools. Sea otters and one population of bottlenose dolphins, for example, use rocks and sponges, respectively, to acquire food while protecting their skin.
- Some groups of humpback whales exhibit a feeding method that is not genetic, but is a learned, cultural behavior. Known as bubble-net feeding, it requires planning, cooperation, and communication among groups of these usually solitary animals.
- In their attempt to attract a mate, humpback whales compose lengthy songs and transmit them across the entire population of breeding males for that region. And as the song slowly morphs over the course of the season, all the males adopt those changes, presumably learning from each other.
- In the 1980s, a researcher noticed a humpback whale in the Gulf of Maine exhibiting a feeding behavior never recorded and named it lobtail feeding. Within ten years, the percentage of humpbacks seen using this technique went from zero to 50 percent, clear evidence of cultural transmission between individuals.
- Bottlenose dolphins, orcas, and false killer whales appear capable of recognizing their image in a mirror. This is an extremely rare ability among animals, and indicates that some marine mammals could be “self-aware.”
Based on these observations and additional exciting research, you’ll learn exactly why Professor Todd concludes that these magnificent animals are indeed intelligent, communicative, and “accomplished” in their own environment to meet their own needs.
The Future of the Oceans
Given the size of the ocean, it’s understandable that humans believed it would be an inexhaustible resource, capable of diluting anything we threw its way. As Professor Todd leads you through the underwater wonders, he also focuses on the history and evolution of the vast entity. You’ll learn how the industrial revolution brought new, unforeseen technologies that possessed the ability to severely impact our environment. Climate change, acidification, and overfishing affect marine populations around the globe. During a relatively short period of time, we “fished” various sea life almost to extinction in the northern Atlantic, including the right whale, California sardines, several species of tuna, Chilean sea bass, and many more. As Professor Todd introduces you to various types of marine life, he also shares which ones are still facing great risks. Even today, many species of albatross, sharks, and sea turtles are in danger of becoming nonexistent.
One of the most important lessons Professor Todd shares in Life in the World’s Oceans is why it’s so important to consider the ocean environment as an entire system. Professor Todd’s passion for preserving the precious resource of the world’s oceans—and the diversity of life within them—is another area where the educational mission and research aims of the Smithsonian were a perfect match. Professor Todd demonstrates the value of using our resources and conservation efforts to protect the ocean environment itself, as opposed to addressing the plight of any species. Professor Todd explains that with a clean, healthy ocean environment, the plants and animals will be able to take care of themselves, just as they have evolved to do. Even more importantly, a healthy ocean will provide resources for continued human survival and success, from food to energy to the oxygen we need for life itself.
Swimming with dolphins, talking to whales, touring the barrier reef, plunging the depths of the seas—these are experiences that very few of us get to share. With Life in the World’s Oceans and the Smithsonian, you get an unprecedented chance to get up close and personal with the underwater world, so you can better understand and appreciate the magnificence of that environment.
American Military History: From Colonials to Counterinsurgents [TTC Video]
18 February 2018, 23:21
Course No 8706 | M4V, AVC, 854x480 | AAC, 160 kbps, 2 Ch | 24x28 mins | + PDF Guidebook | 2.7GB
First in his class at West Point, Wesley Clark took enemy fire while leading an Army patrol during the Vietnam War and was evacuated from the battlefield on a stretcher. But his career did not end with a Purple Heart and a Silver Star. It was only the beginning of a lifelong campaign that culminated as Supreme Allied Commander Europe—and a surgical military victory in Kosovo.
A Rhodes Scholar and thinking man’s officer, Gen. Clark came to master all the tactics, strategy, and historical lore of the U.S. military, the world’s greatest fighting force. In American Military History: From Colonials to Counterinsurgents, he explores the full scope of the nation’s armed conflicts, from the French and Indian War in the mid-18th century to the Global War on Terrorism in the 21st, covering more than 200 years of American diplomacy and warfare. These 24 absorbing half-hour lectures chart the remarkable growth of the United States into the most powerful nation on Earth, thanks in large part to its talent for rising to the occasion when called to war.
He retraces the footsteps of some of his most storied predecessors in uniform—men such as Winfield Scott, Ulysses S. Grant, Robert E. Lee, John J. Pershing, George Marshall, Dwight Eisenhower, Creighton Abrams, Norman Schwartzkopf, and others—through tragedy and triumph; on the road to war, and the winding path to peace.
And Gen. Clark culls important lessons—along with his own wisdom—from history-changing conflicts that nations and their leaders have found so easy to start and so difficult to conclude. In just one of many examples, he reveals the importance of learning from experience through the story of one of the nation’s founding fathers, George Washington, who nearly lost the Revolutionary War before learning how to win it.
The United States won its independence by defeating the British Empire, settled the issue of slavery by fighting the Civil War, and became a superpower by emerging victorious from World War II. Military campaigns have played a crucial role in defining the United States and its place in the world. America may not have won all its wars, but its military history provides a powerful lesson in the causes that motivate its leaders and citizens. And the study of that history underscores the qualities that it takes to prevail on the battlefield, including experienced officers, trained and disciplined soldiers, equipment, logistics, and, above all, a strategic vision.
Paths to Victory
In American Military History, you study warfare the way it’s taught at the United States Military Academy, where Clark was first in his class. Every war, every campaign, every battle is a veritable textbook on possible paths to victory or defeat, among them:
- Surprise: The time to strike is when an opposing force is separated, distracted, and disorganized due to crossing an obstacle such as a river. This is exactly what happened to British Gen. Edward Braddock’s troops while fording the Monongahela River during the French and Indian War—a lesson not lost on his young aide-de-camp, Lt. Col. George Washington.
- Strategy: The Union’s rapid conquest of Fort Donelson during the Civil War showed poor strategy by the Confederates, who lacked a coherent picture of the theater of operations, and it demonstrated superb strategic thinking by the Union commander, Ulysses S. Grant. More than any other general at the time, Grant saw the big picture of the war and how to win it—which he did.
- Simplicity: “In war, there are two kinds of plans,” says Gen. Clark, “those that might work and those that won’t work. You want to pick a plan that might work and then make it work.” In the Battle of Midway during World War II, the Japanese navy had ambitious, multiple objectives, split its forces, and then was ambushed by the U.S. fleet, suffering a crushing defeat.
- Speed: The U.S. armed forces took rapid assault to a new level in the operation to restore order to Panama in 1989–1990, pursuing multiple simultaneous attacks. One aim was to finish the fight before outside pressure could hamper the operation’s successful conclusion. Speed and overwhelming force have become hallmarks of U.S. military doctrine.
- Clarity: Officers are taught from their earliest training to avoid giving ambiguous orders. In the Spanish-American War, President William McKinley’s directive to “reduce Spanish power” and introduce “order and security” in the Philippines, without specifying how, threw a political problem into the laps of the commanders on the scene, with unfortunate results.
- Creativity: In the last lecture, Gen. Clark speculates that “no field of human endeavor sparks as much creativity as warfare.” This is evident in any protracted conflict, which sees new tactics followed by counter-tactics, novel technologies and weapons followed by countermeasures. The watchword among Clark’s fellow officers was, “The enemy has a vote on what works.”
War from the Inside
While any survey of American history covers its wars, this course looks at war from the inside, through the eyes of a soldier who has studied it, lived it, taught it. Among the personal experiences that Gen. Clark relates as he guides you through three centuries of conflict are:
- Fighting insurgents: In 1969–1970, Clark was an army captain in Vietnam during Gen. Creighton Abrams’ implementation of a new strategy to defeat North Vietnamese guerillas. Before he was wounded in action, Capt. Clark saw firsthand the promise of this new approach, which was later abandoned in the politically driven drawdown of American troops.
- Words to live by: In 1976, Clark was a White House Fellow having dinner with Israeli Prime Minister and former Gen. Yitzhak Rabin. He asked Rabin the most important advice he had for a young officer. “Persistence is what wins,” came the answer, and Rabin related a critical battle he fought where persistence won the day when all seemed lost.
- Wars are hard to stop: Once bloodshed starts, wars have a terrible momentum. While negotiating the Bosnia Peace Agreement in 1995, U.S. diplomat Richard Holbrooke insisted, “The most important thing is to stop the killing.” Gen. Clark was the military leader working with Holbrooke’s diplomacy and later commanded NATO forces charged with curbing ethnic cleansing in the region.
Gen. Clark shows how these lessons resonate with past conflicts: with the insurgency that American troops faced in the Philippines after the Spanish-American War; with Gen. Zachary Taylor’s tenacious defense against an overwhelming assault at the Battle of Buena Vista during the Mexican-American War; and with “the shot heard ‘round the world,” which drew the first blood in the American Revolution. “Forces can maneuver, they can deploy, they can threaten, and feint,” says Gen. Clark. “But once the killing starts, passions are aroused, and the stakes expand.”
Available in both video and audio formats, American Military History is especially rewarding in its video version, which has extensive historical engravings, photographs, film clips, and maps, including animated diagrams showing the tactical moves during famous battles. The scores of examples include:
- Andrew Jackson’s defense of New Orleans
- Winfield Scott’s Mexico City campaign
- Ulysses S. Grant’s siege of Vicksburg
- George S. Patton’s counterattack during the Battle of the Bulge
- Douglas MacArthur’s surprise landing at Inchon
- Norman Schwarzkopf’s Operation Desert Storm
Throughout American Military History, you witness large conflicts, small wars of necessity, and wars of choice, actions on America’s shores and far away—on land, sea, and in the air. You learn that certain traditions trace to the country’s earliest years. Among these are the citizen soldier and the principle of civilian control, established by George Washington. Another is a professional officer corps, trained at military academies open to all on a merit basis. When Wesley Clark arrived at the U.S. Military Academy at West Point in 1962, his entering class received an address by retired Gen. Douglas MacArthur, who extolled the three hallowed words in the academy’s motto—Duty, Honor, Country—and reminded the future warriors, “There is no substitute for victory.”
Radio Astronomy: Observing the Invisible Universe [TTC Video]
07 February 2018, 06:25
Course No 1878 | .MP4, AVC, 1280x720 | AAC, 192 kbps, 2 Ch | 24x30 mins | + PDF Guidebook | 11.31GB
It’s easy to imagine the first modern humans staring up at the heavens in wonder, their eyes and minds dazzled by a beautiful band of light splashed across the night sky, the ever-changing moon so large and bright, and pinpoints of light in every direction. For a few hundred thousand years, our eyes were our primary astronomical tool, and we used them well. We catalogued and analyzed what we saw, filled in the gaps with powerful stories, applied what we knew of mathematics, and then invented complex tools of stone, metal, and glass to expand our knowledge. Everything we knew about the universe was based on light, that small part of the electromagnetic spectrum detectable by human eyes.
Then one day in the 1930s, a young engineer named Karl Jansky was assigned a task at Bell Labs: What were the sources of radio static that could interrupt transatlantic radio communications? After several years of work, he identified one source as radio waves coming from thunderstorms near and far… and another, from something at the center of the Milky Way. For the very first time, we had detected radiation below the visible part of the spectrum emanating from an astronomical object. For years, astronomers had been frustrated by interstellar dust that blocked their view and limited their
Radio Astronomy: Observing the Invisible Universe takes you on a thrilling journey through the universe with stunning visuals and animations to explain the science of radio astronomy and its astounding discoveries. Your guide is Felix J. Lockman, Ph.D., of the Green Bank Observatory, an active radio astronomer whose great passion for his work is absolutely contagious. As Dr. Lockman explains, radio astronomy is not simply a conglomeration of theories with no practical application to our lives today. While radio astronomy has the potential to one day answer the question of extraterrestrial intelligence, it also allows us to more accurately tell time right here on Earth, study terrestrial plate tectonics, and even get smartphone directions to that great new restaurant.
All about That Hydrogen
Some of radio astronomy’s myriad discoveries can be traced to the structure of the hydrogen atom. In hydrogen, one electron is essentially in orbit around one proton and both have a property called “spin,” either up or down. The parallel spin “wants” to decay into antiparallel spin—much like two magnets “wanting” to be aligned north to south, or antiparallel. In jumping position from parallel to antiparallel, a photon of radiation is emitted.
This process is certainly not unique to hydrogen. What is unique is that at the dawn of radio astronomy, a scientist predicted hydrogen would emit this radiation at detectable radio wavelengths, and this prediction offered astronomers a new tool for studying the universe. Three teams of scientists from around the world worked to discover the signal, and there it was, exactly as predicted: with a frequency of 1420 MHz, a wavelength of 21 cm.
For more than a decade, hydrogen at 21 cm wavelength remained the only spectral line which radio astronomers could use for their research. Later, signals from other elements and even molecules were identified. Over time, as both theory and technology improved, radio astronomers made discoveries that completely changed our understanding of the universe. Just a very few of these discoveries include:
- Jupiter’s radiation belts;
- Galactic non-thermal radiation, now called synchrotron emission;
- The birth rate of stars in the Milky Way and the galaxy’s rotational speed;
- Sagittarius A, the black hole at the center of the Milky Way;
- Dark matter;
- Neutron stars, pulsars, and binary pulsar systems;
- Gravitational radiation, as predicted by Einstein;
- Cosmic background radiation, confirming the big bang theory;
- Radio galaxies, quasars, and active galactic nuclei;
- Giant molecular clouds, the birthplaces of stars and planets; and
- Complex organic molecules in interstellar space.
Radio Telescopes, “Seeing” the Invisible
While you might have an optical telescope in your backyard, you will likely never have a radio telescope. Radio telescopes are large—over 100 meters in diameter and beyond—because radio waves contain such a small amount of energy. For example, the signal from your cell phone measured one kilometer away is five million billion times stronger than the radio signals received from a bright quasar! Although each radio telescope is designed for a specific use and often looks very different from others, they are all based on the same physical principles. Each collects, focuses, amplifies, and analyzes radio waves. In Radio Astronomy: Observing the Invisible Universe, Dr. Lockman takes you on an exciting virtual tour of radio telescopes. From the first handmade telescope built by radio astronomy pioneer Grote Reber to those on the drawing board for tomorrow, you’re right there with the scientists:
- The Green Bank Telescope, West Virginia, where Dr. Lockman does his research. At 17 million pounds and with more than 2,000 surface panels that can be repositioned in real time, this telescope is one of the largest moveable, land-based objects ever built.
- The Very Large Array (VLA), New Mexico. With its 27 radio antennas in a Y-shaped configuration, the data can be multiplied to form interference patterns, giving scientists a deeper and clearer look at galaxies than ever before.
- The Atacama Large Millimeter/submillimeter Array (ALMA), Chile. With an array of 66 radio antennas located high above much of the earth’s atmosphere, ALMA has revealed new stars and planetary systems in the making.
- The Very-Long-Baseline Array (VLBA), with multiple locations. The VLBA includes telescopes located thousands of miles apart, all functioning together as one single radio telescope the size of the Earth, allowing scientists to peer deep into the centers of galaxies.
The Biggest Questions
Perhaps the most astounding of all radio astronomy discoveries is this: The dominant molecular structures in interstellar space are based on carbon. That is not what scientists had expected.
We have always labeled these molecules “organic” because life on Earth is carbon based. Now we know that the chemistry of the entire Milky Way is organic, not just our home planet, and it is likely that any extraterrestrial galactic life would be related to us, at least on the molecular level. Will we find other organic lifeforms out there? Radio astronomers don’t know. But they’re working on it, along with the study of many other objects and processes not yet understood. Dr. Lockman’s current research addresses hydrogen clouds in the Andromeda galaxy, the nearest major galaxy to the Milky Way. Other radio astronomers are working to answer myriad questions about dark matter, fast radio bursts, and much more.
If the history of radio astronomy is any predictor, discoveries in these new research areas will lead to new questions, new technologies, more discoveries, and more questions. As Radio Astronomy: Observing the Invisible Universe shows, the field is on the cutting edge of knowledge itself. “Astronomy, by looking outward, leads us to questions that reflect upon ourselves in very deep ways,” Dr. Lockman says. “Astronomical discoveries have changed the way we think.”