The second poem is written in iambic pentameter. An iambic foot is a unstressed syllable followed by a stressed syllable. Teachers often try to describe this to their students as the "da-DUM" rhythm, or rather, meter of a poem. (ie: let ME not TO the MAR-iage OF true MINDS).
Pentameter stipulates that there must be 5 iambic feet in each line. While we could identify iambic feet in the first poem, it does not have 5 feet in each line.
Enotes has a great reference article about iambic pentameter structure if you need to mark the meter of your poem with stressed and unstressed syllables. Check it out!