Chapter 29.4, Problem 4R

Summary Introduction

To review:

The relative order of the given sites where lichens are grown, based on their distance from the large city center; other factors that might influence the prediction, and the two big factors that might affect these results.

Given:

The data related to lichens from five survey sites are tabulated as follows in Table 1 below.

Table 1: Number of lichen species and the number of tree branches (in percent) covered in lichen at five different sites.

Site number	Number of lichen species	Percent of tree branches covered in lichens
1	5	38
2	1	2
3	3	15
4	8	75
5	13	100

Introduction:

A lichen is the combination of two organisms that exist together in a symbiotic relationship. A symbiotic relationship is the one in which two organisms live in a harmony without harming each other. In case of lichens, the fungi provide shelter to the under growing algae. The algal partner provides nourishment to the fungi by performing photosynthesis. The lichens are very sensitive to the environmental pollution. The levels of pollution in an area can be detected by checking the number of lichen species present in that area.