It is normal for animals to love being around heat because it is apart of their nature, just as humans should not want to drop their body temperature. Heat can help with regulation in an animal's body, so they feel comfortable and normal.
All plants require light for photosynthesis, the process within a plant that converts light, oxygen and water into carbohydrates (energy). Plants require this energy in order to grow, bloom and produce seed. Without adequate light, carbohydrates cannot be manufactured, the energy reserves are depleted and plants die.
