It's been a long century for the Amur, or Siberian, tiger (Panthera tigris altaica), the
largest of the six remaining tiger subspecies. Once hunted nearly to extinction, just 50
tigers remained when Russia protected the species in 1947. Despite that protection,
illegal poaching soon dropped that number to as few as 20. But enforcement and
careful conservation over the ensuring decades have done wonders, and today the
worldwide Amur tiger population stands at more than 900-421 in captivity and an
estimated 500 in the wild,
But despite that success, future danger could still lurk in the Amur tigers' very genes.
New research led by a team from the University of British Columbia, in Kelowna,
Canada, has shown that Amur tigers in the wild have an "effective population" of just
27 to 35 individual tigers, meaning they show a very low level of genetic diversity-the
lowest, in fact, ever shown in wild tigers.
What mechanism of evolution is this?
Geographic Isolation
bottleneck
natural selection
Founders effect

the answer is d (apex) good luck : ))

the answer is otpion c) understanding

he wants to be heard one more time. he wants to be understood. he needs the truth one more time.

the african cheetah.

this species has a relatively low level of genetic

variation because the population was reduced to a small size approxi-

mately 10,000 to 12,000 years ago.

chapter   outline

24.1

genes in populations and the hardy-

weinberg equation

24.2

factors that change allele and genotype

frequencies in populations

24.3     sources of new genetic variation

population   genetics

24

until   now,   we   have   primarily   focused   our   attention   on   genes  

within   individuals   and   their   related   family   members.   in   this  

chapter   and   chapters   25   and   26   ,   we   turn   to   the   study   of   genes   in  

a   population   or   species.   the   field   of

population   genetics

  is   con-

cerned   with   changes   in   genetic   variation   within   a   group   of   indi-

viduals   over   time.   population   geneticists   want   to   know   the   extent  

of   genetic   variation   within   populations,   why   it   exists,   and   how   it  

changes   over   the   course   of   many   generations.   the   field   of   popu-

lation   genetics   emerged   as   a   branch   of   genetics   in   the   1920s   and  

1930s.   its   mathematical   foundations   were   developed   by   theoreti-

cians   who   extended   the   principles   of   gregor   mendel   and   charles  

darwin   by   deriving   formulas   to   explain   the   occurrence   of   geno-

types   within   populations.   these   foundations   can   be   largely   attrib-

uted to three scientists: sir ronald fisher, sewall wright, and j. b. s.

haldane.   as   we   will   see,   support   for   their   mathematical   theories  

was provided by several researchers who analyzed the genetic com-

position   of   natural   and   experimental   populations.   more   recently,  

population   geneticists   have   used   techniques   to   probe   genetic  

variation   at   the   molecular   level.   in   addition,   staggering   advances  

in   computer   technology   have   aided   population   geneticists   in   the  

analysis   of   their   genetic   theories   and   data.   in   this   chapter,   we   will  

explore   the   genetic   variation   that   occurs   in   populations   and   con-

sider   the   reasons   why   the   genetic   composition   of   populations   may  

change over the course of several generations

acceleration = 18/3 = 6 m/s per second.

hope i

-lavira: )