We’ve talked about the importance of
biodiversity here at To Infinity and…In Theory before, (Livin’ Life to the Extremophile: Biodiversity [Part 4]), but never like this. In
fact, scientists are worried that our dwindling levels of biodiversity on our
planet may be leading us down the treacherous path toward our sixth mass
extinction.
Some of you may be thinking, “What the heck
is a mass extinction?” I assure you, it’s just as terrifying as it sounds, because
for once, the word extinction seems to be apposite to us, humans, homo-sapiens,
your mom and dad, brothers and sisters, it applies to everyone this time. And
if we don’t do something to change the course of current events – something as
drastic as the changes we’ve made that struck us out on this awful road – we’re
going to go the way of dinosaurs.
So how do scientists know this is coming?
From reading and interpreting the Earth’s fossil record. The fossil record is a
detailed analysis of the planet’s history, taking us all the way back to its
inception and through every period in which life almost ceased entirely. Today
at TI&IT we’re going to talk about extinction, fossil records, explain a
little about evolution (and give some proof humans are still evolving), and
we’ll finish up with a short list of some of the species you’ll never get a
chance to see up close because of our direct involvement.
Let’s talk a little bit about how a species
goes extinct first.
Acid Rain, Super
Volcanoes, and Meteoroids…Oh My
Be it multiple continent sized asteroids that
pelted the Earth, erupting super volcanoes, shifting fault-lines, or acid rain,
there are a hundred different theories on what wiped the etch-a-sketch of life
on Earth clean five times prior to the emergence of our first ancestors. There
is one thing scientists are sure of though, the temperature of the Earth rose,
similarly to what is happening now.
The fossil record, which is a collection of
the organisms we have excavated from the Earth over the centuries and igneous
rock contained within the Earth, is like a documentary of the World. Using
methods similar to Carbon Dating (we’ve talked about that before too: How To Politely Ask A Mummies Age) scientists can pin down what was abundant in
the environment and what minerals and gases were almost non-existent.
By searching the area around where dinosaur
bones are exhumed for radioactive isotopes with an excessively long half-life
(Uranium-238, Potassium-40, etc.) researchers can build a blueprint of what was
abundant in the atmosphere before we even came into being. This technique has
been used to prove the age of the Earth and the Moon. (A whopping 4.5 billion
years for both, talk about a geriatric!)
But the fossil record isn’t just dinosaurs
and rock collections. Ice samples and other geological phenomenon are factored
into it as well. Researchers recently in Great Britain at the Universities of
York and Leeds decided it was time to take another look at the fossil record.
Perhaps it would lead them to a better understanding of what was causing huge
numbers of fauna to drop dead on our planet all of a sudden.
What they found is disturbing to say the
least.
Turns out, if they’re findings are correct, a
cold effect may be more beneficial for life on Earth than a warm sunny one.
It’s called “The Icehouse Effect” and it’s the topic of our next section.
The Fridge of Life
We’ve all heard of the Greenhouse effect, but
what’s the Icehouse effect? Well, it’s the opposite of the Greenhouse or
Hothouse effects to be exact, but we’re going to break down the differences a
little bit further. The Greenhouse effect occurs when there is an abundance of
greenhouse gases in our atmosphere, such as methane, Co2, and CFCs. These gases
cause the atmosphere to heat up, trapping UV radiation within the ozone layer
and melting polar ice sheets.
The Icehouse effect is the exact opposite.
Greenhouse gases like Co2 are relatively low in the atmosphere, allowing
dangerous radiation and superheating factors to escape our little bubble,
keeping the surface of the Earth cool. It seems that after analyzing fossil
records, researchers came to one huge conclusion.
Life on Earth thrived during Icehouse
periods.
During Greenhouse periods…well…not so much…
We know that humans are a major producer of
Carbon Dioxide and methane gases through our destructive burning of fossil
fuels and excessive expansion and deforestation methods, but if humans and
Hondas weren’t around 4.5 billion years ago, what caused the temperature to
rise?
O-No-Zone You Didn’t!
There are quite a few theories as to how the
Earth rapidly heated itself up and cooled down as we mentioned before. The most
viable theory however is that of heightened volcanic activity. It’s no secret
the plates inside the Earth’s crust shift, that’s how we went from one big
supercontinent to the seven different continents we have today. But what people
don’t realize is that when continents drift apart, things can get ugly.
Think of it like this. As tectonic plates
shift and move it is literally ripping the Earth apart in order to create new landmasses.
As these plates shift and move it generates an earthquake, these can range in
magnitude, but any earthquake can spell bad news. This increase in tectonic
shifting caused hundreds of volcanoes all across the surface of the Earth to
erupt.
When volcanoes erupt they can spew thousands
of tons of debris and detritus from within. But it isn’t just solid matter
being released from volcanoes. Volcanoes spit out superheated gases as well,
chief amongst them being Carbon Dioxide. Too much of that spills into the
atmosphere and we begin running into hitches and snags.
It gets to a point where plants can’t absorb
the influx of gas coming in and convert it to oxygen fast enough. The gases get
trapped in the ozone layer and bounce around, keeping harmful radiation from
the sun from escaping back into space. When this happens temperatures begin to
rise, polar ice caps begin to melt and a hothouse effect begins to take place.
This is just one theory.
Because the Earth has spent almost 80% of its
existence in this greenhouse state it’s almost impossible to pinpoint the exact
causes. When the planet heats up, ice shelves melt. When that happens habitats
are lost. When habitats are lost the ecology of an area is disrupted. When the
ecology of an area is disrupted, fauna begin to die. Once fauna begin to die,
that’s when we’re in trouble. That’s when we begin to approach levels of mass
extinction.
So if hot’s bad why is cold so good?
Keeping Current
As it turns out, the North and South Poles
may be the key to keeping our current climate in check. Without the niche
ecology they provide we wouldn’t have the diversity of life everywhere else.
Let’s give an example shall we. The whale, possibly the largest creature
currently on this planet, survives on a diet of some of the smallest organisms,
plankton. They screen it off the surface with their large teeth in massive
amounts. Yum.
Plankton is just one of many nutrients found
in our oceans feeding its inhabitants. In colder climates, such as up by the
poles, there are higher concentrations of nutrients in the water for plankton
to thrive. Why? There’s less activity and less organisms to share the plankton
with the whales in cold environments, so they absolutely love it!
So how does plankton end up in warmer
climates? Glad you asked. The answer is, currents.
The currents carry the plankton to warmer
waters. But if there aren’t variations in temperature between areas of the
ocean there wouldn’t be currents. Obviously there are other factors that play
into this as well, such as geological activity and astronomical values, but we
aren’t talking about those today.
So do you get it now?
We’re in a greenhouse period currently.
Greenhouse = Bad.
Icehouse = Good.
So how do we fix this?
First of all the government should probably
pull its collective set of heads out their Gluteus Maximus’ and (I can’t
believe I’m saying this…but…) listen to Al Gore when he says climate change is
upon us. And it’s bad.
Some animals have adapted over the millennia to
survive these fluctuations. The Great White Shark is just one example of a
killing machine that’s been here since the dawn of time. The Duck-Billed
Platypus is another animal that’s been here since time immemorial, however, the
Platty needed to, well, change a little bit over time.
Scientist’s call this evolution. And we’re
still doing it too, just not at a rate nearly fast enough to outrun the damage
we’ve caused. Don’t believe me that your physiology is changing a bit every
day? Let’s lay that to rest next then.
Your Poké-Human is
Evolving
We’ve changed a lot since our first days of
stepping into the sun. Just one example of this is our ability to drink milk.
We weren’t always designed that way. There is an enzyme in our body known as
the LCT gene. Before the domestication of milk producing livestock (cows,
goats, sheep, etc.) the gene would shut down in babies after being weaned off
their mother’s breast milk.
People that are lactose intolerant never
develop that gene. For another example we’ll turn to a piece of literature
first. In Markus Zusak’s amazing novel “I
Am The Messenger” a hapless protagonist named Ed has to help strangers at
the behest of a mysterious individual sending him seemingly random addresses in
the mail. One of these characters he encounters is a young girl named Sophie.
Why is Sophie important to this article you ask? Because she possesses an
interesting trait, she runs barefoot.
Early humans didn’t have Nike’s and Converse
to toss on their feet while they ran away from hungry Tigers and Cheetahs. They
ran barefoot, and as a result the muscles and tendons in the feet and lower
legs developed accordingly. Even if you find well-fitted footwear it’s still
unnatural to squeeze your digits into your Reebok’s and take off for a jog
around the block. We had to evolve again in order to wear such constraining apparel.
Now these kinds of genetic mutations don’t
just spring up overnight. DNA analysis of ancient farmers and herders all over
the world shows that the ability to digest lactose carrying over into
adolescence didn’t spring up until about 8,000 years ago throughout Europe and
India. Running barefoot also took thousands of years to fade away. As I said,
we’re evolving at a quick rate (according to paleoanthropologists anyway) but
not nearly quick enough.
Just ask these guys…oh wait…you can’t…
The Way of the Dodo
Animals have been going extinct for millions
of years. The dinosaurs are a classic example of this, but whenever people
think of extinction that is unfortunately the first place they go. Well as it
turns out, humans are responsible for causing extinctions as well. Just look at
some of these examples below.
That’s the Formosan Clouded Leopard. You’ll
notice that’s a fairly recent, high quality picture, not some pencil drawing
from Charles Darwin’s sketchbook. That’s because the Clouded Leopard wasn’t
officially declared extinct until last year in 2013. (They were really holding
out hope for this one.)
Indigenous to Taiwan, this leopard was the
second-largest carnivore. The Rukai (Taiwanese Aborigines) considered the
hunting of these majestic creatures to be a taboo sin. So how were they pushed
into extinction by us? Through the logging of their habitats. From 2000 to 2004
more than 13,000 camera traps were set up in their last known habitat but none
were spotted in that four year period.
The last known Formosan Clouded Leopard was
confirmed in 1986. None have been “spotted” since.
Yes, I agree. That is one truly, exceptionally,
and wholly ugly bird. However, we shouldn’t have pushed the Mauritius Blue
Pigeon into extinction just because of that. Remember last week when we talked
about the Dutch and the spice trade? (Quick recap here:
Why We Taste: A Brief History of “Thyme” and the Rest of Your Spice Rack). Well
while they were sailing around the Mascarene Islands East of Madagascar, they
encountered this comely looking plumage flying around above them. Only one live
specimen was ever brought back to England, the rest were stuffed.
Like our friend the Clouded Leopard, the
Mauritius Blue Pigeon suffered from his habitat being over logged and the wrath
of hunters. This little fella was classified as extinct almost 200 years ago
now between 1826 and 1830. (Dates vary depending on the source). Regardless of
where in that four year period they disappeared from the face of the Earth one
thing is still apparent, even their relatives, other Blue Pigeons, are at risk
of fading away forever.
Another sad story in the annals of extinction
is pictured above. The Tahitian Sandpiper was pushed into extinction in 1773
when rats were introduced into its habitat. As a result, not much scientific
information is available on this little guy. Only one stuffed specimen is known
to still exist. Five years before him this poor creature depicted below
vanished as well:
That’s Steller’s Sea Cow, and what happened
to him, well, I’ll tell you this much, it wasn’t very stellar. The largest of the
Manatee family known to have shared the Earth with humans was hunted into
extinction. Why? For their meat and the leather that could be produced from
their hides. Humans are so awesome aren’t they? (Total sarcasm…) The last one
of these rotund aquatic bovines was killed in 1768.
While there are literally over 100 examples
of species that humans have shoved out of the picture, for the sake of time the
last one we’ll talk about today is the Mexican Grizzly Bear. Considered a close
relative of the Brown Bear, this was the largest land mammal that roamed the
hillsides of Mexico. The last one was shot and killed in 1960. That was just
over 50 years ago. The Black Rhino was also officially declared extinct last
year, so we’re still doing it.
So there you have it. In this modern world it’s
quickly becoming one of evolve or die. And if we don’t do something about our
rapidly changing climate, we won’t have time to do anything but the latter. If
you want to read more about species we’ve shoved off the cliff you can by
visiting this comprehensive timeline over at Wikipedia by clicking here. Thanks
for reading everyone, and remember…
It’s not just hipster Dodo that thinks
existence is too mainstream.
Soon, our planet could feel that way about us
too…
-
Ryan
Sanders
Thanks for reading
everyone! As always feel free to share this around on Twitter, Reddit,
Facebook, wherever you think the news needs to go! Conservation is extremely
important! If you would like to know more about any of the topics discussed
above today feel free to follow any of the links below! Happy Learning
everyone!
