Planet Earth Notes
Chapter 1: Introduction
Approximately a century ago, the Earth's population was around 1.5 billion. Today, it exceeds 6 billion. Despite the extensive human presence, there remain untouched wildernesses. This series aims to explore those areas, showcasing the planet and its wildlife from a unique perspective.
Consider a world devoid of sunlight.
In Antarctica, male emperor penguins endure the harsh winter, facing continuous darkness and temperatures plummeting to degrees centigrade. These penguins stay behind while other creatures migrate, each guarding a single egg on its feet, kept warm under a downy bulge. They face months without food, water, or sunlight.
As the sun leaves Antarctica, it brings light to the Arctic. In March, after four months of darkness, light returns. A polar bear emerges from her den, marking the beginning of spring. After months of confinement, she slides down the slope, possibly to clean her fur. Her cubs experience the world for the first time. The cubs, hungry and eager, are lured by their mother's milk, their only food since birth two months prior. Having not eaten for five months, the mother bear has lost half her body weight and converts her remaining fat into milk. The spring sun, while bringing warmth, also melts the sea ice, posing a challenge for the mother as she hunts seals to feed her cubs before the ice breaks up.
Despite the emergence, the temperature remains at degrees, requiring the cubs to stay sheltered. Though spring advances rapidly, blizzards can still occur. The cubs, small and easily chilled, are kept active by their mother, who is weakening from hunger. After ten days, the mother leads her cubs a mile from the den, testing their readiness. The ice is already splitting a few miles from the coast, signaling the start of a dangerous hunting journey for the seals. Approximately half of all cubs do not survive their first year.
Summer brings constant sunlight and a thawing landscape. Further south, the snow clears from the Arctic Tundra in Northern Canada, where 3,000,000 caribou migrate annually. The vast herds, constantly moving, undertake the longest overland migration, sometimes exceeding 2,000 miles per year. Newborn calves must be immediately mobile. Wolf packs, consisting of eight to ten members, follow the migration, preying on newborn calves. Their strategy involves running directly at the herd to cause panic and isolate individual targets.
Chapter 2: Energy On Sun
When the herd scatters it becomes easier for the wolves to target individual calves. In the ensuing chaos, a calf may lose its footing, evening the odds between predator and prey. The wolf must succeed quickly, or it will abandon the chase after a mile. During the Arctic summer, the sun remains constantly above the horizon.
Due to the glancing angle of the sun's rays at these latitudes, insufficient energy reaches the ground for tree growth. The tree line, marking the beginning of the boreal forest (taiga), lies 500 miles to the south. The taiga, characterized by needle-shaped conifer leaves, supports limited animal life. This vast forest encircles the globe, containing a third of all trees and producing significant amounts of oxygen. Traveling southward, the sun's influence increases, leading to broadleaved trees replacing conifers at around fifty degrees latitude.
Broadleaves being more digestible, allow animals to collect solar energy more efficiently. These forests teem with life during the summer. However, broadleaves must be shed in winter to prevent frost damage, leading to barren landscapes with scare food. The inhabitants must migrate, hibernate, or endure starvation.
The Amur leopard, with only 40 remaining in the wild, faces extinction due to habitat destruction and hunting. This leopard symbolizes the fragility of nature's heritage. These deciduous forests in Eastern Russia make hunting in winter difficult due to scarce prey and lack of concealing vegetation. The Russian cats have thick fur to combat the cold, unlike African leopards. All animals, regardless of rarity, ultimately depend on the sun for energy.
The arrival of cherry blossoms in Japan signals the start of spring. The sun's energy brings color to the landscape. The Earth's tilt on its axis as it orbits the sun causes seasons. The diminution of the sun in the North causes deciduous forests in America to shed their leaves in preparation for winter. Many organisms prepare for winter, when there is little sun. Populations of animals migrate in search of food and warmth.
300,000 Baikal teal migrate south to Korea to avoid the Siberian winter. In the tropics, the sun's rays are direct and consistent, leading to vigorous jungle growth. Although tropical forests cover only of the planet they contain plants and animals. The canopy is rich with monkeys, birds, and insects. Less than of sunlight reaches the forest floor, even there variety thrives.
Chapter 3: Animals On Move
The print island of New Guinea hosts 42 species of birds of paradise. Male birds focus on display, tidying their areas and calling to attract females.
The sun impacts ocean life, enriching areas where waves and currents bring nutrients to sunlit surface waters. The seas off the Cape of South Africa are productive. Seals breed during the summer. Great white sharks strike quickly, with immense strength. Sharks are faster in straight chases but are less agile the seals.
Great white sharks migrate thousands of miles to harvest seasonal abundances. The sun heats tropical waters, powering weather systems, including storms. Winds crossing the Sahara create sandstorms, fertilizing the Amazon. Winds over the Indian Ocean bring monsoon rains to the Himalayas, distributing water across continents. Deserts cover a third of the Earth's surface and are growing.
In the Kalahari Desert of Southern Africa, elephants and buffalo travel in search of water. They head for the Okavango swamps, a vast inland delta. Dust storms hinder travel, often separating families. The Kalahari's dry-season peak sees water arrive in the Okavango. The water fell as rain a thousand miles away in the highlands of Angola, taking five months to arrive. The water flushes insects that are consumed by plovers, and catfish eat drowned creatures. This creates a seasonal feast.
Chapter 4: The Returning Sun
Nowhere is the life-giving power of water so evident as in the Okavango. Animals create trails that extend the flood's reach, transforming the area into a lush, watery world. Lechwe antelope are at home in the water, using their specialized hooves to move faster through the water. Baboons are less comfortable with the water. The water brings a season of plenty for all species. Hunting dogs work as a team.
Hunting dogs being Africa's most efficient predators. They split up to surround their prey, often an impala. The dogs drive the impala towards the flankers, cutting off its escape. The impala leaps into the lake, where is can barely swim. The dogs wait for it to emerge for the kill.
A pack this size kills once a day, and everything is shared. The elephants conclude their trip. The matriarch encourages them towards water, which they know is nearby. The lives of elephants are dominated by seasonal wet and drought cycles caused by the sun. After four months of darkness, the sun returns to Antarctica. The emperor penguins end their huddle. The males bear eggs during the winter.
The returning sun allows the eggs to hatch. Emperor penguins give their chicks a head start by enduring the winter. These chicks now benefit from the Antarctic summer. A hundred years ago, there were one and a half billion people on earth. Now over 6,000,000,000 crowd our fragile planet. But even so, there are still places barely touched by humanity.
Chapter 5: Energy On Sun
Imagine our world without the sun. Male emperor penguins face the nearest existence on planet Earth, winter in Antarctica. It's continuously dark, and temperatures drop to degrees centigrade. Penguins stay when all other creatures have fled because each guards the treasure, a single egg resting on the top of its feet and kept warm beneath the down bulge of its stomach. There is no food and no water for them, and they will not see the sun again for four months. Surely, no greater ordeal is faced by any animal. As the sun departs from the Antarctic, it lightens the skies in the far North.
It's March, and light returns to the High Arctic, sweeping away four months of darkness. A polar bear stirs her. She has been in her den the whole winter. Her emergence marks the beginning of spring. After months of confinement underground, she toboggans down the soap, perhaps to clean her fur, perhaps for sheer joy.
Her cubs gaze out of their bright new world for the very first time on the survival of a tiny number of mothers like this one. All animals, rare or common, ultimately depends on their energy on the sun. In Japan, the arrival of the cherry blossom announces the beginning of spring. The sun's energy brings color to the landscape. The earth, as it makes its annual journey around the sun, spins on a tilted axis, and it's this tilt that creates the seasons.
The advance of the season brings constant change. As the sun's influence diminishes in the North, so the deciduous forests of America begin to shut down, losing their leaves in preparation for the dark cold months ahead. One season turns over to another. Some organisms thrive on decay, but most must make special preparations for winter and a life with little sun. Whole populations of animals are now forced to travel great distances in pursuit of food and warmth.
300,000 Baikal teal gather to escape from the Siberian winter by migrating south to Korea. The world's entire population in a single slop. But there are parts of the world that have no seasons. In the tropics, the sun's rays strike the earth head on, and their strength is more or less constant all year round. That is why the jungle grows so vigorously and supports so much life.
This forest covers only of the planet's surface, but it contains more than of all plants and animals. The canopy is particularly rich. There are monkeys, birds, and millions of species of insects. Exactly how many, we have no idea. The character of the forest changes as we descend, becoming ever darker and damp, favoring different kinds of animals and plants.
Less than of the sunlight reaches the floor, but even here, there is extraordinary variety. Beginning of the Boreal Forest, the tiger. The needle shaped leaves of the conifers are virtually inedible, so this forest supports very little animal life. It's a silent place where the snow is unmarked by footprints. In the Arctic winter, snow forms a continuous blanket across the land.
But as spring creeps up from the South, the tiger is unveiled. This vast forest circling the globe contains a third of all the trees on earth and produces so much oxygen, it changes the composition of the atmosphere. As we travel south, so the sun's influence grows stronger, and at fifty degrees of latitude, a radical transformation begins. Summers here are long enough for broadleaved trees to replace conifers. Broadleaves are much easier to eat and digest, so now animals can collect their share of the energy that has come from the sun.
It's summer, and these forests are bustling with life. But the good times will not last. Broad leaves must be shed in winter for their damage by frost. As they disappear, so the land becomes barren with little for animals to eat. The inhabitants must migrate, hibernate, or face months of near starvation.
The Amur leopard, the rarest cat in the world. Here in the deciduous forests of Eastern Russia, the winter makes hunting very difficult. Prey animals are scarce, and there's no concealing vegetation. The cubs are a year old and still dependent on its mother. Deer are frequent casualties with the harsh winter, and these leopards are not above scavenging from a corpse.
African leopards could never survive here, but the Russian cats have thick fur to shield them from the cold. There are only 40 animal leopards left in the wild, and that number is falling. Like so many creatures, the cats have been pushed to the very edge of extinction by hunting and the destruction of their habitat. The ammo leopard symbolizes the fragility of our natural heritage. Heritage.
Chapter 6: Conclusion
The future of an entire species hangs. The female calls them, but this Steep Slope is not the easiest place to take your first steps. But they are hungry and eager to reach their mother who's delayed feeding them on this special day. Now she lures them with the promise of milk, the only food the cubs have known since they were born deaf and blind beneath the snow some two months ago. Their mother has not eaten for five months and has lost half her body weight.
Now she converts the last of her fat reserves into milk for her cubs. The spring sun brings warmth, but also a problem for the mother. It starts to melt the seals. That is why she hunts for the seals she needs to feed her cubs, and she must get there before the ice breaks up. For now, though, it's still minus 30 degrees, and the cubs must have the shelter of the den.
It's six days since the day has emerged, and spring is advancing rapidly. But even now, blizzards can strike without warning. Being so small, the cubs are easily chilled, and they will be more comfortable resting in the den. But their mother must keep them out and active. She's becoming weak from hunger, and there's no food on these nursery slopes.
The sea ice still holds firm, but it won't last much longer. Day 10, and the mother has led her cubs a mile from the den. It's time to put them to the test. They've grown enormously in confidence, but they don't have their mother's sense of urgency. At last, it seems that they're ready for their journey, and only just in time.
For a few miles from the coast, the ice is already splitting. Now the mother can start hunting for the seals they must have, but she's leading her cubs into a dangerous new world. Nearly half of all cubs die in their first year out on the earth. Summer brings twenty four hours of sunlight and a thawing shifting landscape. Further south, the winter snows have almost cleared from the Arctic tundra.
Northern Canada's wild frontier. Here, nature stages one of her greatest dramas. Every year, 3,000,000 caribou migrate across the Arctic tundra. The immensity of the herd can only be properly appreciated from the air. Some herbs travel over 2,000 miles a year in search of fresh pastures.
This is the longest overland migration made by any animal. They're constantly on the move. Newborn calves have to be up and running the day they're born. But the vast herds do not travel alone. Balls.
Packs of them, eight to 10 strong, shadow the migration, and they're hungry. It's the newly born calves that they're after. Running directly at the herd is a point to generate panic. The herd breaks up, and now it's easier to target an individual. Calf is young, outrun the wolf if only it manages to keep its footing.
At this Midsummer on the tundra, and the sun does not set. At these latitudes, the sun's rays are glancing, and not enough of their energy reaches the ground to enable trees to grow. You need to travel 500 miles south from here before that is possible. These stunted shrubs mark the tree line that