In looking at Wellman's final chapters, he covers the idea of rights and how one determines who/what has rights. Based on the arguments he presents, it seems that a person/animal/plant must only have representatives to argue for their rights. The example for why this is viable concerns a newborn child, which has rights but no ability to recognize/attempt to protect those rights. Some say that this fact (the ability for babies to have rights) is enough to justify the rights of plants and animals to similar rights (such as the right to life, or those animals/plants wouldn't attempt to survive).
My main criticisms for this are two:
1. The right to try to survive is one I believe all creatures possess, but the main word in that right is "try." History (and most likely pre-history) dictates that survival of the fittest is key in survival, and in order for living things to thrive, other living things perish in that process. This concept seems intrinsic to nature.
2. Referring to the baby argument above, it has one criticism. The difference between babies and plants/animals which can't defend themselves is simple-babies do develop the capacity to determine at least some of their rights, while plants/animals lack the cognitive ability at any point in their lives to understand rights or the concept of having rights. This fact is left out of the reading as far as I can tell, or at the very least not highly considered as a viable criticism.
For me, these criticisms are enough in themselves to override the idea that animals/plants have special rights. Instead, it is up to humans (as we live in a highly social setting compared to any other species, which in part has led to our development of rights conception) to bestow ideas of decency towards animals/plants upon other members of society.