Review of Planet Earth
Mountains
The given documentary shows the planet’s most massive mountain chains and the unique animals dwelling there. It explores the peaks of such mountains as the Ethiopian Highlands, Andes, American Rockies, Alps, Karakoram, and the Himalayas. The plot starts from the Ethiopian Highlands, like one of the lowest and hottest places on Earth. In that context, viewers find out about the Danaki Depression of Ethiopia, a place where giant landmasses are pulling away from one another. The place is unthinkable without a chain of volcanoes that created the Ethiopian Highlands. The documentary explains the origin of these mountains and shows the connection between lava, rain, and ice in creating local canyons. The story also mentions the longest erupting volcano on the planet, Erta Ale.
The documentary not only describes the formation of the mountains, but it also reports about its habitats. It appears that Ethiopian Highlands are the home to some distinctive species, inherent for this place. The matter is that Gelada baboons live here, which is unique for the highlands of Ethiopia. Viewers are invited to get to know about the Gelada’s daily schedule. Geladas are very social monkeys that survive solely due to relying on their class. They live in the largest form of assembly of monkeys and may reach the mark of 800 members. The other unique species to these Highlands is the ibex. Ibexes peacefully coexist with Geladas, and both partners benefit in their alliance for they can guard one another before the predators come. Their common enemy is the Ethiopian wolf that hunts at night.
From Ethiopia, viewers travel to the Andes, the volcanic mountains of South America. It is the longest mountain chain with the most unpredictable weather on the planet. The most noticeable habitats of Andes include guanacos and pumas, the lions of the Andes. Pumas have all chances to survive here for the excellent territory, rich in food and water. Other species are not as likely to survive, partly because of the weather conditions. Severe weather condition is peculiar to the American Rockies, which have nearly 100 000 avalanches every winter. Nevertheless, the slope of the Rockies provides winter refuge for some animals. The program explores the challenges of survival for Grizzlies, in the mountains. It is rather unusual, but according to the documentary, Grizzlies feed on the moth. Bears need to eat something to ensure the survival of their species.
The program continues by reporting about the Alps formation. The famous Mont Blanc - the highest peak in Western Europe is situated there. The Alps have another origin than volcanic. Great mountain sculptors, the glaciers, curbed the distinctive jagged shapes of Alps. They constitute the most destructive force towards the mountain formation. In this context, the viewers may observe the biggest mountain glacier on Earth. It is called Baltoro and is situated in the Karakoram Mountains of Pakistan. Only some species can survive on the steep mountains like this, which include markhors, snow leopards, and golden eagles.
The last mountains shown in the documentary are the Himalayas, the highest mountains of the world, created by a collision of continents. Here in China, the mountain habitats include the giant panda, red panda, golden small monkey, oriental and blood pheasants, and musk deer. On the highest places of our planet, nothing can live permanently. There are only birds in the sky, still having trouble with flying. To reach India, flocks of demoiselle cranes have to cross the Himalayas and its highest peak, the mountain Everest. As these birds cross the mountains, they not only face a risk of the turbulence but also of the predators - golden eagles. Thus, the program explores the challenges of survival in mountain habitats.
Caves
The value of this documentary lays in showing the least explored places on Earth, the caves. The program starts from the biggest cave shaft in the world, the Cave of Swallows, in Mexico. It is 400 meters to the bottom, deep enough to engulf New York’s Empire State Building. Similar to most of the caves, this one consists of limestone, which covers 10 percent of the Earth's surface. The limestone can be shaped by rain and acidic water. The documentary tracks the transformation of the water underground, where it gets its erosive power. During its journey from the surface, the water absorbs carbon dioxide from the soil, making it mildly acidic. Over millions of years, this acid eats the way in this limestone, creating a maze of caverns and passages.
It is exactly the way the biggest underground passage in the world was created, which is in Borneo, and called the Deer Cave. It is said to be so huge, that a jumbo jet could fly through it, and it is still getting bigger due to the erosive waterpower. However, water in caves does not only erode, but it also builds. The documentary provides a step-by-step analysis of the cave’s mineral formation. It explains the origin of stalactites, stalagmites and the limestone columns.
There are many different species living in the caves. The documentary describes the New Zealand glow-worm. The creature learned how to survive in the dark. It produces mucus silver strips that both give the light and a constant source of food for a worm. Meanwhile, two kinds of flying species live in Bornean caves without a light. These are the bats and the little birds, called swiftlets. Both of them navigate in the dark thanks to the echolocation technique. The bats appear to be the key element in the cave “life-organization.” They produce guano, bat droppings, which consist of food for the other cave habitats, such as cockroaches and crabs. While the bats bring profit to the Bornean caves’ habitats, the swiftlets bring profit to the human. People gather the nests of swiftlets and sell them for a high price, as an ingredient of bird’s nest soup.
The next caves shown in the program are the flooded ones, situated in Yucatan, Mexico. The caves remain unchanged for thousands of years, and they are the only local source of fresh water. The cave’s underwater ways have been mapped to some extent, but nobody knows it for certain. However, while people cannot explore the caves, some local habitats can. The remipede, a little crustacean, has been living here for centuries. The documentary also shows the caves with saltwater; particularly half-flooded sea-caves in New Zealand. These were created by a mechanical pounding of the waves, and happen to be a shelter to many fish species. Bats and snakes live in the unsubmerged part of the caves. While the bats can detect the snakes using echolocation, the snakes detect bats by the heat. Other cave habitats include troglodytes, white crabs, and blind salamanders. Living in complete darkness, they all lost their eyes but learned to survive. Adaptation is well shown with the example of fish living in the acidic waters of the Villa Luz sulfur cave and the colonies of bacteria on its walls.
The program ends with the scenes of the most beautiful cave system in the world. It is in the United States and is called Lechuguilla. Its walls are covered with gypsum crystals, the exclusive formations ever seen on the ground. The shots were taken there are unique for it is very difficult to get permission to do that, and they are truly worth it.
