Plants and animals are complex systems that are highly adaptable. In fact, an organisms complexity can contribute to even greater adaptability due to greater variation in the species. Through adaptation, these organisms improve their ability to survive in their environments. While machines cannot autonomously adapt as living organism do, they can be readily modified provided that characteristic was considered and included in their design. Design theorist Josef Saleh explains that systems that have a longer life span are the ones that are capable of coping with uncertainty and changes in their environment. Conversely, if a system is to be designed for an extended design lifetime, the ability to cope with uncertainty and changes has to be embedded in the system. As modern weapons systems have become more complex, they have often traded away their ability to adapt. In fact, the greater the complexity, the more time, cost and effort is typically required to add a new capability, integrate a new weapon, or update operational software. In other words, the more complex a weapon system is developed to be, the less adaptable it becomes.