Expert: John Locke - 11/22/2007

Question
Mr.Locke,what are the advantages and disadvantages to having specialized cells?

Answer
Thanks for using AllExperts, David. Cell specialization is a prerequisite for complex life, so perhaps the biggest advantage of having specialized cells is the ability to become a complex organism. More complex organisms can move greater distances, interact with their environments in more complicated ways, and have more options when it comes to food sources, reproduction, etc. This can help them survive more easily (survival and reproduction the two measures of "success" when it comes to organisms), though survival is a challenge for all species in nature.

None of this should be taken as meaning that specialized, multicellular organisms are somehow "better" than single-celled organisms. We don't classify organisms as better than one another, but we can discuss the kinds of adaptations that they have to their environments. More complex creatures can have more adaptations to their environments simply because they can have more structures in the first place. Let me give you an example: you have relatively complex senses of taste, touch, smell, sight, and hearing. Single-celled organisms have only simple forms of smell and touch, because they have no physical structures that allow for the reception of sound waves (which is required for hearing), the reception of light waves (required for sight), or the reception of taste molecules.

Other possible advantages include greater genetic diversity and greater resistance to environmental change. Finally, you can't ignore a general benefit of specialization of all types: specialized structures usually function more quickly and effectively at a particular job than a general structure trying to do the same job. For example, if you are exposed to disease-causing bacteria, specialized immune cells are able to destroy those bacteria without damaging the rest of your cells. That's all your immune cells are responsible for, besides keeping themselves alive, and as a consequence they're quite good at it.

The major disadvantage to all this is that having multiple specialized, complex cells requires more energy to keep them alive. Complex organisms must eat more food than their simpler counterparts. Since many complex organisms reproduce sexually, they have to compete to find mates (simpler organisms simply divide into two independent parts). Specialized cells often can't survive on their own outside of the whole organism, and their functions are usually essential to the organism as a whole: the loss of a group of specialized cells may cause the death of the organism. You cannot survive without the specialized functions of the cells in the pancreas, nor can your pancreatic cells survive long outside the human body (human cells can be grown in specialized laboratory environments, but only because these environments are very close to the human body itself. Your cells can't survive on their own otherwise).

If you have any further questions, I'd be happy to answer them. Good luck!