Do I have an SSD and a hard drive on my MacBook Pro?
If you consider SSDs being hard drives then you have an SSD and a hard drive on your MBP. It's still only one device with ~500 GB disk space.

The main partition of your SSD is encrypted with FileVault2. While enabling FV2 the main partition is transformed to CoreStorage which is an LVM - an additional layer between physical disk and file system. The resulting Logical Volume is shown as an additional disk in Disk Utility/diskutil info.

A common partition layout looks like this:

disk0 (500.1 GB) → disk0s1 (209.7 MB) EFI
                 ↘︎ disk0s2 (499.4 GB) Macintosh HD
                 ↘︎ disk0s3 (650.0 MB) Recovery HD


disk0s2 (Macintosh HD) is mounted to root (/)

After converting the disk to CoreStorage, disk0s2 is converted to a Physical Volume which sets up a Logical Volume Group. The existing file system on disk0s2 is shrunk a bit, converted to a Logical Volume and encrypted:

disk0 (500.1 GB) → disk0s1 (209.7 MB) EFI
                 ↘︎ disk0s2 (499.4 GB) LVG/PV → disk1    (499.05 GB) LV/Macintosh HD
                                             ↘︎ metadata (~370 MB)
                 ↘︎ disk0s3 (650.0 MB) Recovery HD


Now disk1 (~disk0s2) is mounted to root (/).

So disk1 is almost congruent to disk0s2 (except some 100 MB at the end of disk0s2 which is used for metadata and isn't encrypted).



CoreStorage is not limited to encrypt volumes as FileVault2 "container". Every regular volume can be converted to a CS LVG/PV/LV. Apple uses it to create Fusion Drives and SSDs are usually partitioned/formatted as CoreStorage volumes.