Some Apps, like the stock email app, run services constantly and "self load" sometimes in order to run automated functions like email polling. The iPhone does the same thing by the way, it just doesn't show in the task manager.
To answer your question, no rooting will not stop it from happening by itself. However, rooting allows you to uninstall system Apps, like the stock email App, that you never use but constantly run services. I've done this, and have greatly streamlined my system and running services. Here's a short (LOL!) list of System .APKs (Apps) that I've uninstalled ...
Accuweather.com 11.07.16.01 (SamsungWidget_WeatherClock.apk)
Android Live Wallpapers 2.3.4 (LiveWallpapers.apk)
AP Mobile 11.07.18.02 (SamsungWidget_News.apk)
Books 1.4.5 (BooksPhone.apk)
Buddies now 1.0 (BuddiesNow.apk)
Clock 1.0 (AnalogClock.apk)
Digital Clock 1.0 (DigitalClock.apk)
DRM content 2.3.4 (SisoDrmProvider.apk)
DRM content launcher 1.0 (DrmUA.apk)
DRM Protected Content Storage 2.3.4 (DrmProvider.apk)
Email 1.0 (EmailWidget.apk)
Live Wallpaper Picker 2.3.4 (LiveWallpapersPicker.apk)
Media Hub 129 (MediaHub.apk)
Microbes 2.3.4 (Microbesgl.apk)
N.O.V.A 2 HD 1.1
NASCAR 0.2
Ocean Weather 1.0 (SecretWallpaper1.apk)
Social Hub 2.00.00001 (SocialHub.apk)
Sprint ID 1.5.40 (W_Installer.apk)
Sprint Mobile Wallet 1.5 (SprintMobileWallet.apk)
Sprint Music Plus 1.0
Sprint Radio 1.0.0.0000
Sprint Zone SZ_2.5.12 (SprintZone.apk)
Windy Weather 1.0 (SecretWallpaper2.apk)
Yahoo! Finance 11.07.18.01 (SamsungWidget_StockClock.apk)
As a result, my running services list is pretty short, and I rarely have any Apps in my task manager when I don't want them open. Still, for some Apps that poll a server periodically, it's not completely unavoidable.