Do I need to know about developing web applications to create mobile apps?


So I am looking to learn both web application development and mobile app development, and I was wondering is there is an overlap between the two. More specifically, is the knowledge of developing web apps essential or even helpful when building mobile apps? I was under the impression that one had to know basic web app development first (at least server side programming) before being able to develop mobile apps that use the internet (since I assumed a mobile app is just a different client side that would ultimately have to talk to a web application on a server somewhere). However, Googling this brings up discussions about mobile web apps vs. native mobile apps, and this has me confused (for example is Shazaam a native or a web app?). Please help me understand.

A native app is an app that execute on your mobile. A web app is an app that open a webPage inside your mobile app and act like a classic web browser.

You don't have to know web dev to do mobile dev, but it can help, programming is the same for every platform, you just have to know new language every time you change, but principles are the same.