English for

Reading #2: Population Ecology 
A 
population
is a group of 
interbreeding organisms
that are members of the same species 
living in the same area at the same time. (Organisms that are all members of the same species are 
called 
conspecifics
.) A population is recognized in part by the area in which it resides, and this area 
may have boundaries that are either natural or man-made. Rivers, mountains, and deserts are 
examples of natural boundaries; mowed grass, man-made structures, and roads are examples of 
artificial boundaries. The study of 
population ecology
focuses on the number of individuals in an area 
and how and why population size changes over time. 
For instance, because the Karner blue butterfly is listed as an endangered species by the federal 
government, population ecologists are particularly interested in counting them. However, the 
distribution and abundance of wild lupine, as well as the biophysical environment nearby, have a 
significant impact on the density and population size of this species. Questions about the causes of 
the wild lupine decline and how these affect Karner blue butterflies might be raised by researchers. 
For instance, ecologists are aware that wild lupine thrives in open spaces devoid of many trees and 
shrubs. In the wild, sporadic wildfires regularly burn down trees and bushes to preserve the open 
124
. (credit: modification of work by J & K Hollingsworth, USFWS)
125
Clark M.,Choi, J. Douglas M. (2020) 
Biology 2e
. Chapter 44, 
-Pp 1262-1263. OpenStax, 
https://openstax.org/details/books/biology-2e
)

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spaces needed by wild lupine. The decline of this crucial plant for the Karner blue butterfly can be 
explained mathematically by the suppression of wildfires by humans.