Question

all of these are examples of random evolutionary processes except
a.
an earthquake divides a single elk species into two populations, forcing
them to no longer interbreed.

b.
a mutation in a flower plant results in a new variety.

c.
an especially long winter causes a group of migrating birds to shift their
home range.

d.
a mutation results in a population of trees that spread their seeds more
widely than their peers, causing their population to grow.

Explanation:

随机进化过程（如遗传漂变、突变、自然环境随机变化导致的隔离或迁徙等）是无方向、随机发生的。选项A是地理隔离（地震随机导致种群分离），属于随机进化；选项B是突变（随机发生的基因变化），属于随机进化；选项C是环境随机变化（长冬随机出现）导致迁徙，属于随机进化；选项D中突变使树木更易传播种子、种群增长，这是自然选择（优势性状被选择，有方向性，非随机），因为该突变带来的优势使种群更适应环境而被保留，是定向的选择过程，不属于随机进化过程。

Answer:

D. a mutation results in a population of trees that spread their seeds more widely than their peers, causing their population to grow.