Chapter 26, Problem 17STP

Summary Introduction

To write: The structure that would have an advantage and would be more likely to be naturally selected.

Introduction: Seedless vascular plants show great variety in shape and scale. Some club mosses are tiny plants, typically less than 30 cm long. Club mosses also known as spike mosses and the group of ferns make up the group of seedless vascular plants.

Explanation of Solution

A strobilus is a compact cluster of structures which carry spore. Wind also carries the tiny spores that are formed in the strobilus. When a spore lands in a suitable environment, the gametophyte may expand to size. A fern gametophyte is smaller in size than a ball. This emerges from a spore, which has reproductive systems for both males and females. The sporophyte develops from after fertilization and is briefly reliant upon the gametophyte. One adaptation of some ferns living in dry areas is that they are able to develop sporophytes without fertilization. The sporophyte ultimately grows roots, and a thick underground stem named a rhizome.

Conclusion

Thus, it concludes that in dry areas, the fern can generate sporophyte without fertilization which can be more likely to be naturally selected.