According to the latest studies, there's nearly 1.3 millions of species identified by mankind from the nearly 10 million species that do exist on Earth. From this estimate 8.74 million would be of the eukaryotic kind (that posses a nucleus). We still: Have a lot to learn from our home.

Even when those previous sentences can be used to give a rough sketch of what biodiversity is, this concept is actually not only a recount of species; it covers a broader spectrum of facts.
Biologic diversity -biodiversity- consists on the variety of species on Earth, the genes they posses, the biomes they dwell and the ecosystem exchanges of energy and nutrients they keep running with other lifeforms.

What are biodiversity's components?

Obviously, the property that many may quickly link to diversity is quantity of species. Yet, this is not the only factor. The huge amount of species on Earth hold a much larger variety of genes. Genetic diversity, is a key component in biodiversity (we have a LOT of dogs, but they all have, pretty much, the same genes... A wolf, has different genes).
The more genetic variety there's among species, the more chances there's that several of those will survive and prevail in a changing environment: Adapt and survive.

Ecosystem diversity is also important, this is, variety of deserts, grasslands, woods, jungles, mountains oceans, lakes, rivers, tundras.
Each one of them is a container of unique genetic reserves on Earth.

Last, but not least; there's the functional diversity, the variety of processes that occur in an ecosystem when species interact with each other (meh... eat each other).

Why is this important?

Our destiny relies on biologic diversity, we rely on the richness and variety of live in our planet. It is of utmost importance for a sustainable development of life and, therefore, for our well-being.

Biodiversity is a vital part of the Natural Exploitable Capital. It provides us food, wood, fibers, medicines... It provides, pretty much, whatever you may imagine we have. Preserving by not over-exploiting Nature should always be imperative; and I say "should" because we all know that there's some companies that care little or nothing about how nature will be in 20 years...

---

Over 3000 million people depend on marine biodiversity to survive and other 1600 million depend on woods. Earth's degradation and the loss of biodiversity are threatening over 1000 million people's lives, the ones that live at dry and desert areas.

---

---

Preserving biodiversity should be more than a nice slogan. It should be a primordial concern for all of us, dwellers of the planet. Because, from it, our sole existance deppends