Why is biodiversity so important?
Our planet's diverse,
thriving ecosystems may seem like permanent fixtures but they're actually
vulnerable to collapse. Jungles can become deserts and reefs can become
lifeless rocks, even without cataclysmic events like volcanoes and asteroids.
What makes one ecosystem
strong and another weak in the face of change? The answer, to a large extent,
is biodiversity. Biodiversity is built out of three intertwined features: ecosystem
diversity, species diversity, and genetic diversity. The more intertwining
there is between these features, the denser and more resilient the weave
Take the Amazon
rainforest, one of the most biodiverse regions on Earth due to its complex
ecosystems, huge mix of species, and the genetic variety within those species. Here
are tangled liana vines which crawl up from the forest floor to the canopy, intertwining
with treetops and growing thick wooden stems that support these towering trees.
Helped along by the vines, trees provide the seeds, fruits and leaves to
herbivores, such as the tapir and the agouti, which disperse their seeds
throughout the forest so they can grow. Leftovers are consumed by the millions
of insects that decompose and recycle nutrients to create rich soil.
The rainforest is a huge
system filled with many smaller systems, like this, each packed with
interconnected species. Every link provides stability to the next, strengthening
biodiversity's weave. That weave is further reinforced by the genetic diversity
within individual species, which allows them to cope with changes. Species that
lack genetic diversity due to isolation or low population numbers are much more
vulnerable to fluctuations caused by climate change, disease or habitat
fragmentation. Whenever a species disappears because of its weakened gene pool,
a knot is untied and parts of the net disintegrate.
So, what if we were to
remove one species from the rainforest? Would the system fall apart? Probably
not. The volume of species, their genetic diversity, and the complexity of the
ecosystems form such rich biodiversity in this forest that one species gap in
the weave won't cause it to unravel. The forest can stay resilient and recover
from change. But that's not true in every case. In some environments, taking
away just one important component can undermine the entire system.
Take coral reefs, for
instance. Many organisms in a reef are dependent on the coral. It provides key
microhabitats, shelter and breeding grounds for thousands of species of fish,
crustaceans and molluscs. Corals also form interdependent relationships with
fungi and bacteria. The coral itself is a loom that allows the tangled net of
biodiversity to be woven. That makes coral a keystone organism, one that many
others depend on for their survival. So what happens when destructive fishing
practices, pollution and ocean acidification weaken coral or even kill it
altogether? Exactly what you might think. The loss of this keystone species
leaves its dependents at a loss, too, threatening the entire fabric of the
Ecosystem, species and
genetic diversity together form the complex tangled weave of biodiversity that
is vital for the survival of organisms on Earth. We humans are woven into this
biodiversity, too. When just a few strands are lost, our own well-being is
threatened. Cut too many links and we risk unravelling it all. What the future
brings is unpredictable, but biodiversity can give us an insurance policy, Earth's
own safety net to safeguard our survival.
Source: TED-Ed. Written by Kim Preshoff