What are the Application Pools that SharePoint 2010 creates?

Once we have installed SharePoint, run the Configuration Wizard and the Farm Configuration Wizard, we will have six Applications Pools in addition to those on the machine already. These are details below.

Note: Do not try to change the account used by the SharePoint from the IIS Please change it from the SharePoint central admin

1. SharePoint Web Services RootIdentity: LocalService
   Status: Stoppedthis guy hosts the SharePoint Web Services IIS Web Site and is on every machine in the farm. This is the host web site for Service Applications; it is analogous to the old “Office Web Services”. Service Applications WCFs are hosted in here as Applications which can (and should) be run in a different Application Pool. Whilst the IIS Web Site is important for bindings and other configuration, it is OK that this Application Pool is stopped. If you try to browse the site, you will get a 503.
2. SharePoint Central Administration v4Identity: SharePoint Farm Account
   Status: StartedThis one is pretty straightforward. It’s responsible for Central Administration on the machines hosting it. It will include at least three applications (root, images, inc) plus an app for each Language Pack you have installed
3. SharePoint Web Services System (which is named with a GUID)
   Identity: SharePoint Farm Account
   Status: Startedthis person hosts the Topology Service Application, which is known as the Application Discovery and Load Balancer Service Application.
4. SecurityTokenServiceApplicationPool (which is named with a GUID)
   Identity: SharePoint Farm Account
   Status: StartedThe guy hosts the Security Token Service Application, required internally even on a single server farm as well as for supporting inter-farm operations, and external Claims.
5. SharePoint Web Services Default (which is named with a GUID)
   Identity: SharePoint Services Account
   Status: StartedThis is the big daddy. It hosts all the other Service Applications. You will have as many applications in here as you do service applications deployed unless you configure their hosting manually.
6. SharePoint – 80
   Identity: SharePoint Services Account
   Status: StartedThis is the default application pool used to host end user Content Web Applications having used the Farm Configuration Wizard to get up and running quickly.

check the following site this was my refrence

http://www.harbar.net/archive/2009/12/04/more-on-sharepoint-2010-application-pools.aspx