How is the loss of biodiversity related to the loss of genetic diversity?

Biodiversity means the diversity among a group, so, if the diversity
among the group is decreasing, meaning that the people among the group
are growing more and more alike, then the genetic diversity will
decrease because people of like-type will mate as opposed to having
more genetic diversity where there to be an increase in biodiversity.

Biodiversity describes the diversity of a system, genetic diversity
describes the diversity of a species. Take a look at Kansas or
Austrailia for example,I mean if Kansas is all (except for pockets of
wildlife) corn fields, mice, crows, and foxes, it has a smaller degree
of biodiversity than the rain forests of the Amazon of South America.
(Please don't ask me to describe the dominant food web of the Amazon).
But how does that relate to the loss of genetic diversity? Possibly a
loss of bio (or ecological) diversity decreases the stresses necessary
for genetic mutations to become successful. (eeww, Where's the spell
check on this thing?)

Yeah marhead, take a look at Kansas.  Perfect example of lack of
genetic diversity. ;-)

http://www.cnn.com/US/9908/12/kansas.evolution.flap/

In recent news: 
http://news.google.com/news?q=kansas+board+of+education
http://www.kansascity.com/mld/kansascity/news/local/11025534.htm

Diversity results because of two things in particular:
1.The Genetic material
2.The environment
  In reference to your question. under circumstances of exactly
similar environments all the biodiversity is caused only because of
the genetic differences.
 Biodiversity we usually refer to by the morphological variations that
are observed quite clearly by eye or by physiological variations that
can be examined via study.These variations within a single specie
occur because presense of different genes at a gene locus i.e. at the
site on the DNA strand where the gene is normally present.These
different genes are known as alleles.
Presense of two or multiple alleles causes the variation in the
phenotype i.e. the external appearance of an organism in terms of
morphology or physiology.
 Now biodiversity arises just because this particular reason that the
different species cannot mate with each other because of very large
physiological and /or morphological differences.Also variations in the
same specie may arise because of the different alleles that code for a
given single trait (assuming the nigligible impact of environment).
  Thus if there is decrease in biodiversity, it will lead to loss of
some paricular alleles or genes from the environment.This loss may be
irrepairable because most alleles are generated via chance
mutations.Thus yhis permenant loss will cause permenant disappearance
some traits resulting into loss of genetic diversity.
This may have very adverse effects on the ecology of the land as the
organisms now may not be able to cope with the new diseases or
natuaral disasters like ice ages.