For quite some time, fungi were considered to members of the plant kingdom. This classification was because they have similarities to plants and share the same morphology and growth habitats. In addition, they both contain a cell wall, which is not present in the animal kingdom. But now fungi are considered to have a separate classification of their own that is not part of the animal kingdom or plant kingdom. There have been many studies done that identify characteristics of fungi that make them different from other classifications.
Some of the differences between fungi phylogeny and other animal and plant kingdoms is that they have their own morphological, genetic and biochemical features. This separates the fungi from other kingdoms and allows them to have their own.
Much like animals and unlike most kinds of plants, fungi do not have the ability to synthesize carbons by photosynthesis. Plants store the carbon as starches and fungi use glycogen stores for carbohydrate storage. A major part of the cell wall in most of the fungal species is the carbohydrate or chitin and is also present in some animals. The plant wall consists mostly of cellulose. The unique characteristics of fungal cells include those of hyphae, which are small filaments, which when combined together form mycelium. Most kinds of fungi do not have a very efficient vascular system that prohibits long distance transportation of nutrients and water.
There are some characteristics that are shared between plants and fungi and include having vacuoles in the cell, similar pathways of terpenes in biosynthesis and biochemical precursors. Plants use more kinds of terpene biosynthesis in the chloroplasts that seem nearly absent in fungi.
There are ancestral traits that plants and fungi share also, including chitinous cell walls and the ability of heterotrophy by absorption. Fungi produce many kinds of secondary metabolites that function as defensive compounds but the biochemical pathways for synthesis are different between the two of them.
The first organisms that have shown to have features similar to fungi can be traced as far back as 1200 million years ago. These fossils of fungi do not seem to have been made common until quite some time after that period. Fungi are now typically thought to be more related to animals than to plants, which have taken quite a switch in the classification of the plant and animal kingdoms.
Fungi phylogeny and the ancestral roots can be shown through the use of cladograms. Cladograms help show what kinds of fungi have changed in their similarities over the course of millions of years going back to their ancestral roots. There is really not a generally agreed upon system at high phylogeny levels and there are constantly name changes that are taking place. There are a lot of efforts by researchers of fungi to help encourage and establish the use of more consistent and universal nomenclatures. This can also help create more universal names for fungi phylogeny.