No, a Will and a Power of Attorney are completely separate and do different things. When creating your Will you will also find that there is no section appropriate for listing a Power of Attorney to carry out your wishes. Instead, you will appoint an Executor to carry out the requirements and wishes under your Will.
On the other hand, a Power of Attorney appoints someone you nominate to take care of such things as some of the financial decisions on your behalf when you are unwilling, unable or just wanting some assistance to manage your affairs. A Will organises your personal affairs after your death. Your Will and any directives or provisions in your Will do not come into effect while you are alive.
Any Power of Attorney ceases to exist upon your death so that any directive provided under your Power of Attorney will be redundant and the Power of Attorney becomes ineffectual after you pass away. Only one document can be in effect at one time depending on the your personal state.
Both documents are similar …
Both documents do generally have a similar effect, one operating while you are alive and one operating after your death. It is important to remember that although they seem to have the same function, what is stated in one does not have any effect on the other.
Your Will appoints an Executor who will take an appointed role after you pass away whilst the person you appoint in your Power of Attorney takes on the role and activities you have given them the power to do while you are alive.