We have isolated around 30 or 40 strains already of unicellular eukaryotes.

Malavin：我们已经分离出大约 30 或 40 株单细胞真核生物。

Why don't we get unicellular elephants, or blue whales, or brown bears?

为什么我们得不到单细胞大象、蓝鲸或棕熊？

Most unicellular reproduction is asexual, meaning one organism, on its own, can reproduce itself.

大多数单细胞繁殖是无性的，这意味着一个生物体可以自行繁殖。

But these could be the fossils of colonial unicellular organisms, bacterial mats, or something else entirely.

但这些可能是殖民地单细胞生物、细菌垫或其他完全不同的东西的化石。

Those are simple, unicellular life forms that thrive without oxygen and get energy by scavenging what molecules they find.

这些是简单的单细胞生命形式， 它们在没有氧气的情况下也能茁壮成长，并通过清除它们发现的分子来获取能量。

Yet even the biggest unicellular organisms have limits, and none grows nearly as large as the elephant, whale, or bear.

然而， 即使是最大的单细胞生物也有局限性，没有一种能像大象、鲸鱼或熊那样长得那么大。

If that's true, though, then there's a problem: Most unicellular life at the time was photosynthetic -- like cyanobacteria and phytoplankton – and they need light to live.

不过， 如果这是真的，那就有问题了：当时大多数单细胞生命都是光合作用的——就像蓝藻和浮游植物一样——它们需要光才能生存。

In the 1940s, author Jack Williamson coined the term, " terraforming." To terraform is to create an ecosystem that supports living organisms—from large, complicated vertebrates, to simple, unicellular bacteria.

在 1940 年代，作家杰克·威廉姆森 (Jack Williamson) 创造了“地形改造”一词。地形改造就是创造一个支持生物体的生态系统——从大型、复杂的脊椎动物到简单的单细胞细菌。

For 2 billion years, all organisms on Earth are unicellular, and they likely lived in the oceans, shielded from the hard ultraviolet light of the sun but then something remarkable happened, Photosynthesis.

20亿年以来，地球上的所有生物都是单细胞的，它们很可能生活在海洋中，不受太阳紫外线的照射，但随后发生了一件非同寻常的事情，就是光合作用的产生。

A further argument against the simple wear and tear theory is the observation that the time within which organisms age lies between a few days (even a few hours for unicellular organisms) and several thousand years, as with mammoth trees.

反对简单磨损理论的另一个论点是观察到生物体老化的时间介于几天（对于单细胞生物甚至是几个小时）到几千年之间，就像猛犸象树一样。