Does it? Where? The ‘just’ and ‘no more than’ are unnecessary and invalid value judgements. They’re not there in Darwin, who goes out of his way to avoid making any such statement, while Richard Dawkins explicitly rejects the idea that we are ‘just’ gene carriers.
Evolutionary theory recognises that humans are indeed animals – with no ‘just’ or ‘no more than’ to qualify the fact. How can we not be animals? We do everything they do; like them, we have – indeed are – physical bodies that breath, eat, sleep, excrete, bond, mate, experience pain and pleasure and fight; we are, like most other animals, territorial and also like them, we put a great deal of effort into ensuring our own survival and that of our offspring. Even Christians who deny the body and its demands engage in these kinds of animal behaviour.
Of course, we also do things other animals don’t, or don’t to the same extent; we have remarkably complex social arrangements, which have resulted in our developing systems of morality and sophisticated ways of dealing with each other (though our morality is remarkably flawed); we have achieved much in the fields of culture, technology and in our understanding of the world and the universe beyond our tiny planet. We have also made a mess of our environment.
Our intelligence, our self-awareness, is the evolutionary equivalent of adaptations developed in other species. Our characteristics may seem to us to be somehow superior to those of other animals, but really they’re not. They have enabled our continued survival and allowed us to achieve all that we have, both good and bad. But in evolutionary terms, they are no different from the refinements that have enabled other animals to do the equivalent in their environments. This doesn’t mean, however, we are ‘just’ or ‘no more than’ animals. No creature is ‘just’ an animal and human achievements are all the more remarkable because we’re animals.
What Christians usually mean by their ‘just’ and ‘no more than’ is that as animals we are not extra-special to God, not ‘made in his image’. And of course, we’re not; there’s no God to be extra special to or made in the likeness of. Even if there were, he doesn’t seem to be particularly pre-disposed towards us; we exist as physical bodies that are as susceptible to the same hunger, disease, illness, injury, weakness, infirmity and death as any other animal. We are not immaterial, spiritual beings – though presumably the Christian God could have made us that way if he’d wanted to. To say, as some Christians do, that we are spiritual beings temporarily trapped in material bodies, or that we must deny the body and its demands to become spiritually perfect, is the grand perversion that is the Christian faith. It denies the reality of this physical, material world and our own natures. Any spirituality we might claim for ourselves is a projection of our intelligence and self-awareness; any morality the result of those complex social arrangements.
So, we are not ‘just’ animals, nor are we ‘no more than’ animals in any way that makes sense biologically. We are animals, remarkable perhaps in rising above our biology from time to time, but animals nonetheless, whether Christians want to believe it or not. ‘Just’ and ‘no more than’ don’t come into it.