Shots of Earth from space. The voice of a man you can’t see, but know you can trust.
One hundred years ago, there were one and a half billion people on earth. Now, over six billion crowd our fragile planet. But even so, there are still places barely touched by humanity.
So begins Planet Earth – a documentary series by the BBC and Sir David Attenborough that is so highly esteemed by us here at Nothing in Biology that we’re celebrating its 10 year anniversary by devoting the next 10 weeks to it. We’re reliving the majesty and checking in on some of our favorite places, organisms and phenomena. Essentially, we wondered “Where are they now?” Are any species better off than they were ten years ago? Have any gone extinct? How are we doing in terms of protecting the biodiversity hotspots?
This series will take you to the last wildernesses and show you the planet and its wildlife as you have never seen them before.
We see breathtaking landscapes, terrifying heights, beautiful creatures and gruesome battles. We see millions of animals moving together and solitary animals rarely seen by humans. We see the highest peaks and the deepest depths. This series is the definition of awesome. Each week, we’ll embed full episodes and/or clips in the posts (the series is also on Netflix) for convenience but if you’re reading this and the links don’t work – definitely find another way to watch/re-watch/re-re-watch.
The first episode, From Pole To Pole is an overview episode that starts in Antarctica with the charismatic Emperor Penguin.
“Imagine our world without sun.”
As is true of many polar species, and especially true of species that use sea ice, there is much concern over the effects of global climate change on emperor penguins. Accordingly, some work has gone into assessing their current population sizes. Emperor penguins became the first species to have their population size estimated from space. The first recorded loss of an emperor penguin colony has been reported, and it is associated with rising local air temperatures and declining sea ice. Also, some modeling has been done, which suggests that global warming may result in a catastrophic decline of this species over the coming century.
On the organismal biology front, there has been tremendous interest in the emperor penguin’s ability to dive to extreme depths in search of prey. Recent work has established that they can dive as deep as 564m. Physiological research has shown that this ability is facilitated by an extreme slowing of heart rate (going from 85bp at rest to 6bpm at the end of very long dives) and the ability to survive blood oxygen levels so low that they would be “catastrophic” in many birds and mammals.
“A polar bear stirs.”
Next, we follow a mother polar bear and her two adorable cubs. Even more than emperor penguins, polar bears are a species of extreme concern when it comes to the effects of climate change. Their dependence on sea ice, and their fate as it declines has been the subject of much research and discussion, so I won’t go into it much here.
There are, however, other environmental concerns. It turns out that some pollutants from industrialized regions of the world find their way to parts of the arctic and reach high concentrations (PCBs, PBDEs). Some of these can be bioaccumulate, and because polar bears are at the top of the arctic food chain, there has been some research demonstrating high concentrations of these chemicals in their bodies and suggesting these could be a threat to the health of their populations, even effecting the bone density of male bears’ bacula. [Penises and penis bones are a long-standing interest of this blog].
Among novel research findings, in contrast to other bears, polar bears avoid bone density loss during hibernation. The mechanism may prove to be of medical importance to humans because bone loss with age, during prolonged bed rest and IN SPACE are problems.
“The immensity of the herd can only be properly appreciated from the air.”
Moving south across the arctic tundra, we next see the great Caribou migration. As in, 3 million migrating caribou, the longest distance of any overland migration by any animal. Caribou are still very numerous in 2016, but declining and have been extirpated from some regions, while some other ungulates (e.g., Moose, White-tailed deer) are expanding northward into some of their former habitat. The mechanisms of decline are unclear, so much recent research has gone into trying to understand the interplay of climate change, direct anthropogenic alterations to habitat and predation.
“…a third of all the trees on earth.”
Boreal forests: low animal density, but massively important. They’re also massively threatened – by… you guessed it, climate change, but also by industrial resource extraction (logging and tar sands being major factors). Check out this map from globalforestwatch.org of forest loss in northern North America since 2006:
Because boreal forests are so extensive and contain so much biomass, they hold huge amounts of carbon. As we all know, concentrations of carbon dioxide in the atmosphere are the primary driver of global climate change, so understanding the dynamics of these forests, their fate in a warming climate, and their role in carbon cycling through the atmosphere has been a major research priority.
“…at 50 degrees latitude, a radical transformation begins.”
Broad-leaved forest, complete with easy to digest food for herbivores. We’re treated to a relatively rapid montage through Eurasia and finally see a highlight of the episode – the rarest cat in the world, an Amur Leopard and her cub. In one of the bright spots for conservation in this episode, the number of this species has increased from 40 at the making of Planet Earth to around 70 today! HUZZAH!
“All animals, rare or common, ultimately depend for their energy on the sun.”
Next we see Japan’s Cherry Blossoms and some super cool time-lapse videos of seasonal change. A common theme in climate change research in northern latitudes is the ever earlier arrival of spring. Because Japan’s cherry blossoms are so culturally important, there are over 1200 years of data on the blooming of cherry trees available. Big surprise, these data reinforce that theme. Cherries in Japan are now blooming earlier than ever in recorded history.
A couple of bird species of note are also shown in this sequence: Baikal Teal and European Starling. Baikal teal are strongly recovering from a population crash in the mid-20th century, with some reports having their population increasing by up to several hundred thousand birds in the last decade. European starlings, however, are declining in Europe (almost 80% in Britain), though they remain an abundant invasive species in North America.
“There are parts of the world that have no seasons.”
The focus then moves to tropical forests, and some more really amazing footage, this time of birds of paradise in New Guinea. I mean – this footage is truly spectacular. There is not much work done on these birds (uncommon rainforest birds on New Guinea aren’t the most pliable study system). On the conservation front, they share with all spectacular rainforest creatures twin threats of poaching and habitat loss.
“Life in the oceans”
The episode then shifts focus to the oceans, and another iconic sequence: Great White Sharks feeding off the coast of South Africa. Life hasn’t gotten any easier for Great White Sharks in the last ten years, they are still hunted for teeth, fins and trophies and they are still a victim of bycatch. Oceans in general aren’t faring that well – suffering from overfishing, climate change and pollution. On the plus side, some conservation efforts in North America have led to an increase in population size in the eastern Pacific Ocean. Yay!
“…a search for water.”
Perhaps the most heartbreaking scene from the whole documentary follows a mother elephant and her baby in the Kalahari Desert, as they are separated from the herd and then separated from each other. The baby is last shown alone, following its mothers scent but in the wrong direction, to almost certain death. As you could probably guess, African Elephants are still in serious danger, with ivory poaching driving a global decline in their numbers (as many as tens of thousands a year). Saving these creatures requires international efforts – perhaps some more demonstrations like the destruction of ONE TON of ivory products that New York City held in Times Square last year.
“After four months of total darkness, the sun rises once more rises over Antarctica.”
We revisit the Antarctic as the episode ends – going Pole To Pole as the title episode promises. Be sure to come back next week when we revisit Episode 2: Mountains.
PS – There are now ~7.4 billion people crowding our fragile planet. And counting.
Noah contributed equally to this post.