Many algae, for example, have sex cells that are indistinguishable in size.

例如，许多藻类的生殖细胞大小难以区分。

Unless land organisms return to the water to reproduce or have specially adapted sex cells, their options are limited.

除非陆地生物回到水中繁殖或有特别适应的生殖细胞，否则它们的选择是有限的。

It does not always involve strictly female and male individuals with differently sized sex cells that fuse internally.

它并不总是严格涉及拥有不同大小内部融合的生殖细胞的女性和男性个体。

Typically, the little sex cell is much littler than the big sex cell.

通常，小性细胞比大性细胞小得多。

This happens around half-moons, when weaker tides calm the water's surface, creating the perfect conditions for their sex cells to couple up.

这发生在半月时候，当较弱的潮汐让海面平静，为它们的生殖细胞配对创造了完美的条件。

For males, which have the small sex cell, you don't have the same thing.

对于具有较小性细胞的男性来说，则没有相同的东西。

But some species that have sex cells can undergo a type of asexual reproduction called parthenogenesis — meaning " virgin origin" in Greek.

不过，一些具有性细胞的物种可以进行一种无性繁殖，即“孤雌生殖”，在希腊语中是“处女起源”的意思。

Males are the smaller of the sex cells; females are the bigger.

雄性是性细胞中较小的；女性较大。

Ostracods are still around today, and many species seem to share this ability to create enormous male sex cells.

介形虫今天仍然存在，许多物种似乎都具有这种创造巨大雄性性细胞的能力。

Each primordial follicle has a single immature sex cell called the primary oocyte at the core, and a layer of follicular cells surrounds this.

每一个始基卵泡中心都有一个未成熟的生殖细胞，叫做初级卵母细胞，被卵泡细胞包裹。

Because females have these big sex cells, they typically incubate them internally.

因为雌性有这些巨大的性细胞，所以它们通常在内部孵化它们。

Nondisjunction means the chromosomes don't split apart - so following meiosis, one resulting sex cell ends up with both chromosomes and the other gets none.

不分离意味着染色体没有分开，所以在减数分裂后形成的两个细胞中，一个拥有2条染色体，而另一个一条都没有。

Recombination occurs uniquely in each sex cell— making two sisters' chromosomes different not only from their parents', but from each other's.

在每个性细胞中发生的重组都是独一无二的——使两姐妹的染色体不仅不同于她们父母的，而且也不同于彼此的。

Part of what they found was that the structure of the sex cells was virtually identical to those in ostracods living today.

他们发现的部分原因是性细胞的结构与现代介形类动物的性细胞结构几乎相同。

Each follicle is initially made up of an immature sex cell, or primary oocyte, which is the female sex cell, and layers of theca and granulosa cells surrounding the oocyte.

每个卵泡最初是由未成熟的生殖细胞：初级卵母细胞（即女性生殖细胞）和卵母细胞外层的鞘细胞、颗粒细胞组成。

As they go from a cell with 46 chromosomes to a sex cell with only 23, the chromosomes within each pair swap some sections.

当它们从一个有 46 条染色体的细胞变成一个只有 23 条染色体的性细胞时，每对染色体中的染色体会交换一些部分。

By definition, when biologists talk about this, animals that are males have a little sex cell, which carries genes and nothing else – sperm cells.

根据定义，当生物学家谈论这一点时，雄性动物有一个小性细胞，它携带基因， 而不携带其他东西——精子细胞。

Animals that are females have a big sex cell, which has genes but also food and a protective cover and all sorts of other stuff.

雌性动物有一个很大的性细胞，其中有基因， 还有食物、保护罩和各种其他东西。

When the bodies of our forbearers created their sex cells, the cells engaged in genetic reshuffling, meaning each of the 23 chromosomes is a unique combination of an original pair.

当我们祖先的身体产生性细胞时，这些细胞会进行基因重组， 这意味着 23 条染色体中的每一条都是原始对的独特组合。

The logic goes like this then: difference in the size of sex cells leads to differences in typical parental investment, leading to differences in the sorts of psychological and physiological mechanisms that evolved.

逻辑是这样的：性细胞大小的差异导致典型的亲代投资的差异，从而导致进化的心理和生理机制的差异。