The Ethernet connection you see in your virtual machine is not really a true Ethernet connection. That is, it's not a physical one.
It is a network adapter, and the VM sees it as one, but it is really more of a network bridge between the VM and the host. If you're using Windows, you'll see that your Network Connections window will have a VMNet
adapter (one for each VM). This is the adapter that acts as the other end of the VM network bridge, allowing the virtual OS to access your physical network connections indirectly.
You don't see your WiFi adapter in your VM, but you don't see your Ethernet adapter either, as it is a virtual connection between host and VM. This bridge allows the VM to access the host's internet connection, which is over whichever network connection the host is using. As far as I know, you cannot add your WiFi adapter to the VM. If you can, then it most likely disables it for the host, which is the case for quite a few devices.
There should be no reason to use WiFi in a VM, and if there is a need, I recommend you actually install Ubuntu or use a Live Environment.