Final answer:
UV radiation damaging the dermis and initiating melanomas can affect fitness negatively.
Step-by-step explanation:
UV radiation can damage the dermis and initiate melanomas, which are a type of skin cancer. This damage occurs when the skin is exposed to repeat UV radiation, such as from the sun. Overexposure to UV radiation when young can increase the risk of developing melanoma later in life. This can affect fitness because melanoma is a serious health condition that can lead to complications and reduce overall well-being.