1. The ancestors of plants were photosynthetic single-celled organisms that gave rise to plants presumably lacked true roots, stems, leaves, and complex reproductive structures such as flowers.
语言点：that...flowers为定语从句修饰single-celled organisms, 从句中lacked...flowers为过去分词做定语修饰plants。
参考译文：植物的祖先是能够进行光合作用的单细胞生物体，此类生物生成了可能缺少根、茎、叶及像花一样的复杂的繁殖结构的植物。
2. In addition, other lines of evidence support the hypothesis that land plants evolved from ancestral green algae used the same type of chlorophy II and accessory pigments in photosynthesis as do land plants.
语言点：that...land plants为hypothesis的同位语从句，句中plants做主语，evolved...green algae为分词结构修饰land plants, used为从句中谓语动词，as do land plants表示类比。
参考译文：另外，其他证据证实了这个假说，最早的绿色海藻演化来的植物像现在的陆地植物一样使用同一种叶绿素及色素进行光合作用。
3. Water temperature can fluctuate seasonally or even daily and changing level of rainfall can lead to fluctuations in concentration of chemical in the water or even to period in which the aquatic habitat dries up.
语言点：and连接前后两个并列句。in which the aquatic habitat dries up为定语从句修饰period, even to是lead to的第二个结果。
参考译文：水温会发生季节性甚至日常波动，降雨量的变化能够导致水中化学物质含量的变化及导致水栖息地变干。
4. From a plant’s evolutionary view point, however, it was also a land of opportunity, free of competitors and predators and full of carbon dioxide and sunlight (the raw materials for photosynthesis, which are present in far higher concentrations in air than in water).
语言点：free of competitors and predators and full of carbon dioxide and sunlight中free of and full of为并列形容词修饰a land of opportunity, 句末括号中的内容修饰carbon dioxide and sunlight。
参考译文：从植物进化的角度，陆地最初是充满机会的，没有竞争者与捕食者，并且充满了二氧化碳及阳光(二氧化碳和阳光是光合作用的原材料，空气中的含量远超过水中的含量)。
5. They include roots or root like structures, a waxy cuticle that covers the surfaces of leaves and stems and limits the evaporation of water, and pores called stomata in leaves and stems that allow gas exchange but close when water is scarce, thus reducing water loss.
语言点：a waxy cuticle...the evaporation of water，and pore...water loss与root like structures并列。
参考译文：它们包含根结构，覆盖叶面及茎并能限制水分蒸发的柔软的表皮，叶子及茎部叫做气孔的小孔，这种小孔可以进行气体交换，并在当水稀少的情况下闭合以减少水分流失。
6. So the most successful groups of land plants are those that evolved methods of fertilized sex cell dispersal that are independent of water and structures that protect developing embryos from dying out.
语言点：that evolved methods of fertilized sex cell dispersal that are independent of water and structures that protect developing embryos from dying out为定语从句修饰those, that are independent of water and structures修饰methods, and structures that protect developing embryos from dying out与methods并列，其中that protect developing embryos from dying out做定语修饰structures。
参考译文：最成功的陆生植物有两个特征，一：能够进化出不需要依靠水进行受精卵传播的方法;二：能够保护胚芽的结构。
7. There are two general classes of vegetation: long-lived perennials, which may be succulent and are often dwarfed and woody, and annuals or ephemerals, which have a short life cycle and may form a fairly dense stand immediately after rain.
语言点：which may be succulent and are often dwarfed and woody为定语从句修饰long-lived perennials, which have a short life cycle and may form a fairly dense stand immediately after rain为定语从句修饰annuals or ephemerals。long-lived perennials与annuals or ephemerals二者并列。
参考译文：植被一般分为两类：一种为多水的、矮小的、木质的多年生植物;另一种为生命周期较短并且雨后立即生产的较密集的一年生植物或暂生植物。
8. The tropics contain a larger surface area of land than higher latitudes---a fact that is not always evident when we examine commonly used projections of Earth’s curved surface, since this tends to exaggerate the areas of land in the higher latitudes---and some biogeographers regard the differences in diversity as a reflection of this effect.
语言点：a fact指代The tropics contain a larger surface area of land than higher latitudes所表达的意思，since this tends to中的this指代Earth’s curved surface, as a reflection of this effect中this effect指代The tropics contain a larger surface area of land than higher latitudes。
参考译文：热带地区比高纬度地区有广大的地表面积——当我们检查经常使用的地球弧形表面的推算方法时这个事实有时候并不明显，因为地球弧形表明经常夸大高纬度地区的地表面积，一些生态地质学家将多样的区别归因于热带地区地表面积更大这个因素。