Few ferns are capable of growing in full sunlight, although bracken is a common exception. Ferns are common in tropical rain forests, where temperature,light and humidity are favourable.
The Protoctista contains eukaryotes that are generally regarded as identical or similar to the ancestors of modern plants, animals and fungi. It includes organisms which resemble early plants, early animals and early fungi. It also includes a group known as the slime moulds which produce produce spores like fungi but can creep slowly over surfaces and are therefore motile like animals. The earliest eukaryotes were probably unicellular organisms which moved by beating flagella.
Saprotrophic organisms feed on dead organic material. Fungal saprotrophs produce a variety of digestive enzymes. If they secrete the three main classes of digestive enzymes, namely carbohydrases such as amylases, lipases and proteases, they can utilise a wide range of substrates. For example the Penicillium species form green and blue moulds on substrates such as soil, damp leather, bread and decaying fruit.