Chapter 20.2, Problem 5MI

Summary Introduction

To summarize: 

The evidence to support the initial classification of chytrids as protists and later reclassification as fungi. 

Introduction:

The Chytridiomycota are commonly known as chytrids. They are worldwide in distribution Living chytrids such as Batrachochytrium dendrobatidis  are mostly aquatic. They live in fresh water, marine waters and on land. Chytrids produce zoospores with flagella.

Explanation of Solution

Chytrids are like protists:

Chytrids produce zoospores. The zoospores have single flagella. They are able to move through aqueous environments with the help of a single flagellum. Based on presence of flagellum, initially chytrids are classified as protists.

Chytrids are like fungi:

Chytrids have chitin in their cell walls like other fungi. But one group of chytrids has both cellulose and chitin in the cell wall. Most chytrids are unicellular and a few form multicellular but their hyphae are aseptate. The DNA sequence and protein is similar in chytrids.

Conclusion

Chytrids are like protists due to flagellated zoospores and chytrids are like fungi due to similar protein and DNA sequences and chitin-containing cell walls.