Chapter 31.5, Problem 14SAQ

Summary Introduction

Vascular plants are defined as any plants that exhibit xylem and phloem, the vascular tissues. The vascular plants composed of all seed-bearing plants such as gymnosperm and angiosperm and the pteridophytes such as ferns, horsetails, and lycophytes. Gymnosperms are defined as a group of seed-producing plants such as cycads, conifers, gnetophytes, and ginkgo. The term “gymnosperm” indicates “naked seeds”. Gymnosperms lack flowers or fruits and possess unenclosed seeds on the leaf surfaces. Unlike gymnosperms, angiosperm’s seeds are enclosed in a flower. The fertilization of eggs of angiosperms results in the development of seed in an ovary, which resides in a flower.

Explanation of Solution

The wind-pollinated angiosperms usually have small flowers but have a large amount of pollen whereas, animal-pollinated angiosperm have larger flowers but less pollen.

The movement of a pollen grain from an animal-pollinated angiosperm is effective compared to the wind-pollinated conifer. This is because the wind-pollinated angiosperms (plants) can reproduce only if their populations are high in numbers. As no wind-carried pollen is probably to fall on isolated individuals, low population density species may go extinct.

On the other hand, since animal pollinators effectively search for rare species, they can persist at decreased population densities.