That's the allele frequency of the tomato color gene in that population.

这就是这个群体中番茄颜色基因的等位基因频率。

Evolution is simply the change in allele frequencies in a population over time.

进化只是一个种群中等位基因频率随时间而产生的变化。

The few remaining tomatoes just happen to have an allele frequency of 10% big C and 90% little c.

剩下的几个番茄恰好有 10% 的大 C 和 90% 的小 C 等位基因频率。

Let's go back to our original tomato population with the 70% big C and 30% little c allele frequency.

让我们回到原来的番茄群体 70% 的大 C 和 30% 的小 C 等位基因频率。

But if one or more of them occurs, evolution is possible, and those allele frequencies can start to change like symbols on a slot machine.

但如果其中一个或多个发生了，进化就是可能发生的，这些等位基因的频率就会像老虎机上的符号一样开始改变。

The other three forces of evolution probably aren't going to cause huge changes in allele frequencies like genetic drift or natural selection do; but they still can have an impact on how evolution occurs.

进化的其他三种力量可能不会像遗传漂变或自然选择那样引起等位基因频率的巨大变化；但它们仍然可以对进化的发生产生影响。

Non-random mating won't change allele frequencies, but will change the combinations of alleles in a population, those pairings of two big C's, two little c's, or one big C and one little c.

非随机交配不会改变等位基因的频率，但会改变种群中等位基因的组合，那些两个大 C，两个小 C，或者一个大 C 和一个小 C 的配对。

So if we return to those tomatoes a hundred years from now and find that the allele frequency has changed to 50% big C and 50% little c, we'll say that the population of tomatoes has evolved.

所以，如果一百年后我们再看回这些西红柿，发现等位基因频率已经变成了 50% 的大 C 和 50% 的小 C，我们就可以说西红柿种群已经进化了。