Most stars, and their planets, appear to form within filamentary structures within giant molecular clouds. These filaments funnel the stars into central hubs, where the filaments intersect. Most stars and planets, therefore, form in groups where the relative proximity to other stars can affect both their formation and evolution.
In this thesis, I begin by investigating how we can quantify and model the substructured nature of star-forming regions. Contrary to recent work, I find that the well-established Q-parameter method remains an appropriate analysis for determining the amount and type of substructure in observed star-forming regions. However, the main components of the Q-parameter should not be directly compared to idealised geometries, such as synthetic box-fractals and Plummer spheres, that have not undergone dynamical evolution.
I then run N-body simulations of planets in star-forming regions and investigate how their evolution may be affected by dynamical interactions with other bodies. Two possible outcomes for a planet are its capture or theft. In planet capture, a planet is first ejected from its original system by a dynamical interaction, and is then free-floating before being captured by a passing star. In planet theft, a planet is directly exchanged between two passing stars. I find that planets that have been captured and stolen have distinct orbital properties, and it may therefore be possible to observationally distinguish populations of them.
Finally, I consider the destructive effects that photoevaporation can have on the formation of planets whose orbits are later disrupted. I find that many planets that are disrupted or ejected from their system in previous studies, such as my own, may not fully form due to external photoevaporation of their protoplanetary disks.
