5 Things You Didn’t Know Sharks Do for You

The explosive popularity of "Sharknado" and its recent sequel - as well as the annual success of Shark Week, which began Sunday night on the Discovery Channel - has continued to prove that humans are both fascinated by and petrified of these creatures.

In reality, you are more likely to be killed by your toaster than a shark ... and if sharks were to disappear, it would be bad news for all of us. Here are just a few of the reasons why.

1. Sharks keep the food web in check.

Many shark species are apex predators, meaning they reside at the top of the food web. These sharks keep populations of the species they prey on in check, weeding out the weak and sick animals to keep the overall population healthy. Their disappearance can set off a chain reaction throughout the ocean - and even impact people on shore.

For example, a study found that large sharks have declined dramatically in the northwest Atlantic since the mid-1980s. The presence of fewer sharks led to a population explosion of species like cownose rays, which in turn depleted the region's bay scallops. This was an important factor in the collapse of North Carolina's century-old bay scallop fishing industry.

2. Sharks could hold cures for diseases.

It has puzzled researchers for years: Why don't sharks get sick? (They do, of course, but not as often as other species.) Shark tissue appears to have anticoagulant and antibacterial properties. Scientists are studying it in hopes of finding treatments for a number of medical conditions, including viruses, cystic fibrosis and some forms of cancer.

Read the rest of the list on Conservation International's blog, Human Nature.