Article] Why is sex so unpopular in the Australian desert?

[Robert Karl Sto]

plant from the Australian arid zone highlight an emerging trend toward the

this pattern should provide important information about the relative

clonally. Although such organisms are taxonomically rare (0.1% of recognized species), they exhibit
striking patterns with respect to the ecological circumstances in which they occur. For instance,
when compared with closely

to higher latitudes, higher altitudes, arid environments and to environments described as transient,
ecotonal, disturbed or marginal. Such patterns, called 'geographic parthenogenesis', have attracted
the attention of many researchers in the hope that they might shed light on a major problem in

has not yet been reached as to the processes responsible for these patterns

reproduction from the arid interior of the Australian continent. These new cases, in a lizard and in
a tree, show remarkable similarities and

evolved in association with hybridity and/or polyploidy. Together, they represent one of the most
spectacular examples of geographic parthenogenesis.

Read the rest at BioMedNet http://news.bmn.com/magazine/article?pii=S0169534703003136

Kind Regards, Robert Karl Stonjek.

 

[Wirt Atmar]

Robert quotes:

>

>plant from the Australian arid zone highlight an emerging trend toward the

>this pattern should provide important information about the relative

lizards in deserts -- whether that desert resides in the Australia, North America or Asia -- is the
"weed species" concept of John Wright and Chuck Lowe:

WRIGHT, J. W. AND C. H. LOWE. 1968. WEEDS, POLYPLOIDS, PARTHENOGENESIS, AND THE GEOLOGICAL AND
ECOLOGICAL DISTRIBUTION OF ALL-FEMALE SPECIES OF CNEMIDOPHORUS. COPEIA 1968(1)- 128-138.

density falls to a critical level, it faces the exigencies of demographic extinctions (local
populations composed of all one gender, individuals too dispersed to easily find each other, etc.).
When this occurs, species go locally extinct.

is episodically (but not predictably) disturbed (flash floods, etc.). Under

interspecific hybridizations, prove themselves to be more demographically "competitive" in the sense
that they can invade newly disturbed habitat faster and persist more easily as viable populations at
extremely low densities, even though they are often otherwise physiologically, ecologically and
behaviorally incompetent competitors.

in a manner that they never could given more clement conditions.

Wirt Atmar