Botkin Environmental Science Earth as Living Planet 8th txtbk

CHAPTER
8
Biological Diversity
and Biological Invasions
LEARNING
OBJECTIVES
Biological diversity has become one of the “hotbutton”
environmental topics—there is a lot of news
about endangered species, loss of biodiversity, and
its causes. This chapter provides a basic scientific
introduction that will help you understand the
background to this news, the causes of and solutions
to species loss, and the problems that arise when
we move species around the globe. Interest in the
variety of life on Earth is not new; people have long
wondered how the amazing diversity of living things
on Earth came to be. This diversity has developed
through biological evolution and is affected by interactions
among species and by the environment. After
reading this chapter, you should understand . . .
Yellow dragon disease—huanglongbing in Chinese, “citrus greening”
in the United States, represented in China by this iconic symbol
for the disease, is a growing threat worldwide to citrus crops. The
reason this is a threat has to do with patterns of biodiversity and
how people interface with these.
How biological evolution works—how mutation,
natural selection, migration, and genetic drift lead
to evolution of new species;
Why people value biological diversity;
How people affect biological diversity: by eliminating,
reducing, or altering habitats; harvesting;
introducing new species where they had not lived
before; and polluting the environment;
When and how biological diversity is important to
ecosystems—how it may affect biological production,
energy flow, chemical cycling, and other
ecosystem processes;
What major environmental problems are associated
with biological diversity;
Why so many species have been able to evolve
People around the world are wearing masks
and persist;
to protect themselves against swine flu.
The concepts (Source: of the http://www.baltimoresun.com/news/
ecological niche and habitat;
nation-world/ny-swineflu-photos,0,859331.
The theory photogallery of island biogeography;
[Getty Images Photo / May 2,
2009].)
How species invade new habitats, and when this
can be beneficial and when harmful.