Networks surround and sustain us, in nature, in our bodies, in relationships, in the digital world. On this week's show, TED speakers explore how we rely on networks and how we have the power to shape them.

Ecologist Suzanne Simard shares how she discovered that trees use underground fungi networks to communicate and share resources, uprooting the idea that nature constantly competes for survival.

Wanis Kabbaj wants traffic to flow smoothly and efficiently, like the blood in our veins. He says driverless cars may be the solution to today's highway gridlock.

Computer scientist Avi Rubin says all our smart devices -- cars, phones, even fitness trackers -- can be hacked. He warns that our network of connected technology puts us at increased risk for cyberattacks.

Anthropologist Robin Dunbar believes the evolutionary structure of social networks limits us to 150 meaningful relationships at a time -- even with the rise of social media