UML diagrams question regarding composition/aggregation of Base class - does the Derived class need diamond link?

Question

Hi. If, for example, I have the following requirements: 
1. Dog is an Animal 
2. Zoo has Animal(s) 
Do I still need the 2nd diamond connector (the lower one) as shown in the image below: 

https://docs.google.com/drawings/edit?id=1TlnDD8LrqPo-J9_gfHdGm6Y9BpeqC8N-c6Cnc9bPwko&hl=en&authkey=CNLq5bYB

Thanks. 

Answer 1

The 2nd diamond connector is redundant. Here is some advice about UML class diagrams style: http://www.agilemodeling.com/style/classDiagram.htm

Answer 2

The 2nd diamond connector suggests that in addition to animals the Zoo also has specifically Dogs.

Answer 3

Hi before tackling UML use your common sense :)

Do you want to model that zoo have animals of different species ? Then you should not only put dogs but also cats and all other animals class that can exist in THIS zoo type (class) and just use one diamond connector.