天擇：练习题

• a.

  The bacteria learned to avoid the areas where the antibiotic concentration was highest

• b.

  They already possessed a genetic mutation providing resistance, which they passed to their offspring

• c.

  The antibiotic caused the bacteria to mutate their genes to become resistant

• d.

  They developed a resistance specifically because they were exposed to the drug

• a.

  The two populations stop breeding to prevent the mixing of genes, which causes an immediate change in species type.

• b.

  Mutations occur at a fixed rate in both populations, causing them to eventually become identical through genetic engineering.

• c.

  Genetic variation exists in both populations; different alleles are selected in different environments until interbreeding is no longer possible.

• d.

  The animals acquire new characteristics during their lifetime to survive, and these changes are passed to their offspring.

• a.

  They are acquired during the organism's lifetime and then transferred to the offspring.

• b.

  They cause the individual to mutate rapidly to ensure it becomes a new species within one generation.

• c.

  They are passed on to the next generation because the individual is more likely to survive and breed successfully.

• d.

  They remain dormant until the environment changes, at which point they become dominant alleles.

• a.

  A person who loses a limb in an accident does not have children who are missing that limb

• b.

  Certain strains of bacteria can evolve resistance to antibiotics over many generations

• c.

  Polar bears have thick layers of fat and fur to survive in cold arctic environments

• d.

  Giraffes with slightly longer necks are more likely to survive during a severe drought

• a.

  Genetic engineering \(\rightarrow\) therapeutic cloning \(\rightarrow\) environmental variation \(\rightarrow\) creation of clones.

• b.

  Geographical isolation \(\rightarrow\) uniform selection pressures \(\rightarrow\) reduction in genetic variety \(\rightarrow\) speciation.

• c.

  Geographical isolation \(\rightarrow\) genetic variation in each population \(\rightarrow\) natural selection of different alleles \(\rightarrow\) inability to interbreed.

• d.

  Environmental change \(\rightarrow\) inheritance of acquired characteristics \(\rightarrow\) geographical isolation \(\rightarrow\) rapid mutation.

先自己写一遍答案，再对照解题步骤。

先自己写一遍答案，再对照解题步骤。

先自己写一遍答案，再对照解题步骤。

先自己写一遍答案，再对照解题步骤。