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  • 植物类前体人的特点 -- -- 先进

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    Many people, if not most, believe seaweed to be a plant. Is it?
    ::许多人,如果不是大多数人,相信海藻是植物,是吗?

    Seaweed is actually a plant-like , which are also known as . The green color is due to what pigment? Algae, like plants, obtain their energy through .
    ::海藻其实是种植物, 也被称为 。 绿色的颜色是由什么色素造成的? 藻类,像植物一样,通过植物获得能量。

    Characteristics of Plant-like Protists
    ::类似植物的原生者的特点

    Plant-like protists, also called algae are a large and diverse group of simple plant-like organisms . Some algae are tiny and unicellular, others are large and multicellular, as shown in  Figure . The largest and most complex forms are called seaweeds. They are considered "plant-like" because they photosynthesize, and are considered "simple" because they do not have the distinct organization of higher plants such as leaves and . All algae are eukaryotic organisms. All algae, therefore, have a enclosed within a membrane and bound in one or more membranes.
    ::植物类原生生物,也称为藻类,是一大批种类繁多的简单植物类生物。如图所示,有些藻类是微小的、非冰质的,另一些藻类是大的和多细胞的。最大和最复杂的形态被称为海藻。它们被认为是“种植类”的,因为它们光合体大小,并且被认为是“简单”的,因为它们没有树叶等较高植物的独特组织。所有藻类都是黄藻类生物。因此,所有藻类都封闭在膜内,并装在一个或多个膜内。

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    Example of plantlike protists, from very large kelp (left), to the microscopic marine dinoflagellate Karenia brevis (right). K. brevis is common in waters of the Gulf of Mexico and is the organism responsible for Florida Red Tide. K. brevis produces a powerful neurotoxin that kills marine life and can endanger people if they eat contaminated seafood. Kelp forests, found in many marine waters, are one of the most productive and dynamic ecosystems on Earth.

    Features
    ::特征特征

    Features that are shared by most algae include the following:
    ::大多数藻类共有的特征包括:

    • Body form – Algae live as unicellular, colonial, filamentous, or truly . Unicellular, colonial, and filamentous body types as shown in  Figure .
      ::单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞,如图所示。 单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞、单细胞。
    • habitats – They are found only in habitats that have , such as ponds, streams, rivers, and oceans. They are also found in damp environments such as leaf litter, forest floors, and soil .
      ::它们只存在于池塘、溪流、河流和海洋等生境中。 它们也存在于草叶、森林地底和土壤等潮湿环境中。
    • Gametangia – A gametangium is a structure in which gametes are produced by multicellular algae. A gametangium is a haploid structure, like the rest of the of the alga. The formation of gametes does not involve .
      ::游戏塔吉亚 — — 游戏台是一个由多细胞藻类生成的游戏台的结构。 游戏台是一个像其他藻类一样的杂交结构。 游戏台的形成并不涉及游戏台的形成。
    • Photosynthetic pigments – Photosynthetic protists contain chlorophyll a , chlorophyll b , and other, non-chlorophyll pigments called accessory pigments . Some algae may contain chlorophyll c or d .
      ::光合色素 — — 光合色素原体含有叶绿素a、叶绿素b和其他非氯素色素,称为附属色素。 有些藻类可能含有叶绿素c或d。
    • Pyrenoids – A pyrenoid is a center of carbon dioxide fixation within the chloroplasts of algae. Pyrenoids are not , they are specialized areas of chloroplasts. Pyrenoids are not found in higher plants. Pyrenoid bodies are structures, also found in algae and usually store starch .
      ::类固醇 — — 类固醇是藻类叶板内固化二氧化碳的中心。 类固醇不是,它们是叶板的专门领域。 类固醇在较高植物中找不到。 类固醇是结构,也存在于藻类和通常储存的淀粉中。
    • Flagella – Many algae have flagella at some point in their life.
      ::国旗 — — 许多藻类在其生命的某个时刻都有旗子。
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    (left to right) Unicellular algae of the colonial protist Pediastrum duplex, the genus Staurastrum, and filamentous algae of the genus Spirogyra.

    Summary
    ::摘要

    • Some algae are tiny and unicellular, others are large and multicellular.
      ::有些藻类微小且没有卵巢,有些藻类则大且多细胞。
    • The largest and most complex marine forms are called seaweeds.
      ::最大和最复杂的海洋形式被称为海藻。
    • Algae are considered simple, plant-like organisms. They are "plant-like" because they photosynthesize and "simple" because they do not have the distinct organization of higher plants such as organs and vascular tissue.
      ::藻类被认为是简单、植物类有机体。它们是“植物类”生物,因为它们光合和“简单”因为它们没有器官和血管组织等较高植物的独特组织。

    Review
    ::回顾

    1. What characteristic do all plant-like algae share?
      ::所有植物类藻类共有什么特征?
    2. What function does the gametangium have in algae?
      ::在藻类中有什么功能?