I have a CR1000A Verizon Fios router properly configured for my home network. Everything works fine. However, I am confused about the settings under Port Forward in the router configuration:

I like to think I'm pretty knowledgeable about network configuration, but I'm confused about these settings. Is this the default configuration for this router?
My concern is that these settings are poking holes in my firewall. Take the HTTP setting, for example. Does this mean that if someone from outside tries to connect to my home network using an HTTP request on any port, that the router will re-router that connection to port 80? And then what? I tried connecting to my public IP from outside the network via a web browser, but it didn't connect,'
What will happen if I delete all of these rules? Will someone in my network break? I have UPnP enabled.