Nature provides a number of irreplaceable services to humans. We all know about the most basic services like food, water and oxygen. But there are many more lesser known services without which our existence will be at stake.
One such wonder is horseshoe crabs. Unlike hemoglobin in vertebrates to transport oxygen throughout their body, horseshoe crabs use hemocyanin. This gives their blood a distinctive blue color. Unlike white blood cells, the crabs have amebocytes. When amebocytes comes in contact with a pathogen, it releases chemicals that causes local blood to clot. This property of horseshoe crabs is extensively used in medical research, products and practices to isolate dangerous pathogens and is so valuable that one quart of horseshoe crab blood can fetch $15,000.
The game changing discovery of this property led to high demand for the crab's blood. Companies harvest as many as 600,000 crabs a year, drain upto 30% of their blood before returning them to the ocean. This process is highly traumatic for the crabs and in absence of proper handling and transportation care can lead to high mortality rate among these valuable crabs. Overharvesting has pushed this species to 'vulnerable' state as per IUCN red list.
Thankfully, a synthetic substitute has now been invented to perform the same tasks. But this should be a warning call for us. Over exploitation by humans has pushed the most unique species to the brink of extinction. If we hadn't been able to invent the synthetic alternative, we would have faced the consequences of a species extinction in a hard way pretty soon.
There are many such unique important services provided by the natural world. Some are known to us, some are not. If we keep exploiting them for profit, destroy their habitats or food sources, push them towards extinction, a day will come when we won't have a substitute and the damage will be irreversible.