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  • General

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  • 原体特征

    Paramecium cells dividing, illustrating asexual reproduction in protists.

    Sexual or asexual reproduction for protists?
    ::性还是性生殖 给原生者?

    Notice how the Paramecium is dividing into two . This, obviously, is a form of . But, remember that are an extremely diverse , and some protists can also reproduce sexually.
    ::注意Paramecium是如何被分成两个的。这显然是一种形式。但是,记住这是一个极为多样化的,一些原生者也可以进行性繁殖。

    Characteristics of Protists
    ::原生学家的特征

    Like all other eukaryotes , protists have a containing their . They also have other membrane-bound , such as and the . Most protists are single-celled. Some are multicellular. Because the protist kingdom is so diverse, their ways of getting food and reproducing vary widely.
    ::与所有其他的欧卡利奥特人一样,原生主义者也有包含它们的东西。他们也有其他的膜,例如和它。大多数原生者都是单细胞的。有些是多细胞的。由于原生国是如此的多样化,他们获取食物和繁殖的方式也大相径庭。

    Protist Habitats
    ::原生生境

    Most protists are aquatic organisms . They need a moist environment to survive. They are found mainly in damp soil , marshes, puddles, lakes, and the ocean. Some protists are free-living organisms. Others are involved in symbiotic relationships. They live in or on other organisms, including humans.
    ::大多数原生生物是水生生物,它们需要潮湿的环境才能生存。它们主要存在于潮湿的土壤、沼泽、水坑、湖泊和海洋中。有些原生生物是自由生物。另一些则涉及共生关系,它们生活在包括人类在内的其他生物中。

    Motility of Protists
    ::原生主义者的多才多才多艺

    Most protists have motility . This is the ability to move. Protists have three types of appendages for movement . As shown in Figure , they may have flagella , cilia , or pseudopods (“false feet”). There may be one or more whip-like flagella. Cilia are similar to flagella, except they are shorter and there are more of them. They may completely cover the surface of the protist cell. Pseudopods are temporary, foot-like extensions of the cytoplasm .
    ::多数蛋白质有运动功能。 这是运动的能力。 蛋白质分子有三种运动的附种。 如图所示, 他们可能有旗状、 仙子或假假肢(“ 假脚 ” ) 。 可能有一种或多种类似鞭子的旗状。 Cilia 和 旗状 类似 , 除了短的和更多的。 它们可能完全覆盖蛋白细胞的表面。 Pseudopods 是细胞板块的暂时的、 脚相似的延伸 。

    Examples of protists with different appendages for movement: cilia, pseudopods, and flagella.

    Protists use cilia, pseudopods, or flagella to move.
    ::Protisists使用西里亚、假人或白旗来移动。

    Protist Reproduction
    ::生殖

    Protists have complex life cycles. Many have both asexual and . An example is a protist called Spirogyra , a type of , shown Figure . It usually exists as haploid cells that reproduce by binary fission . In a stressful environment, such as one that is very dry, Spirogyra may produce tough spores that can withstand harsh conditions. Spores are reproductive cells produced by protists and various other organisms. If two protist spores are close together, they can fuse to form a diploid zygote . This is a type of sexual reproduction. The zygote then undergoes , producing haploid cells that repeat the cycle.
    ::蛋白质的生命周期很复杂。 许多人都有性与性。 一个例子是一个叫Spirogyra的蛋白质, 一种类型的, 显示图 。 它通常以二进制裂变繁殖的杂交细胞形式存在。 在压力很大的环境中, 比如非常干燥的环境中, Spirogyra 可能会产生坚硬的螺旋, 能够承受严酷的条件。 Spirogyra 是先质和各种其他有机体生产的生殖细胞。 如果两个蛋白质的螺旋体相近, 它们可以结合成一个浸泡状的zygote。 这是一种性生殖的种类。 zygote然后进行繁殖, 产生重复循环的杂交细胞。

    Microscopic view of Spirogyra algae, showing filamentous structure with rectangular cells.

    Spirogyra is a genus of algae with a complex life cycle. Each organism consists of rectangular cells connected end-to-end in long filaments.
    ::Spirogyra是具有复杂生命周期的藻类基因组,每个生物体由长丝状的端到端连接的矩形细胞组成。

    Protist Nutrition
    ::蛋白营养

    Protists get food in one of three ways. They may ingest, absorb, or make their own organic molecules .
    ::原生者以三种方式之一获得食物。他们可以食用、吸收或制造自己的有机分子。

    • Ingestive protists ingest, or engulf, and other small particles. They extend their cell wall and around the food item, forming a food vacuole . Then digest the food in the vacuole.
      ::孕育先锋会吞食,或吞没,以及其他微小的微粒。它们扩大了细胞壁和食物的周围,形成食物真空。然后将食物消化到真空中。
    • Absorptive protists absorb food molecules across their cell membranes. This occurs by . These protists are important decomposers .
      ::吸收性蛋白质分子吸收食物分子跨过细胞膜。这是由 . 这些蛋白质分子是重要的分解者。
    • Photosynthetic protists use light energy to make food. They are major in .
      ::摄影合成原生者使用光能制造食物,

      

     

    Summary
    ::摘要

    • Protists have nuclear membranes around their DNA. They also have other membrane-bound organelles.
      ::原生者在他们的DNA周围有核膜。他们还有其他含有膜的有机体。
    • Many protists live in aquatic habitats, and most are motile, or able to move.
      ::许多原生生物生活在水生生境中,大多数是运动的,或能够移动。
    • Protists have complex life cycles that may include both sexual and asexual reproduction.
      ::原生者有复杂的生命周期,可能包括性生殖和性生殖。
    • Protists get food through ingestion, absorption, or photosynthesis.
      ::原生者通过摄食、吸收或光合作用获得食物。

    Review
    ::回顾

    1. Identify three structures that protists use to move.
      ::确定三个原生者用来移动的结构。
    2. Describe three ways that protists get food.
      ::描述三种方法 原生主义者得到食物。
    3. Describe asexual and sexual reproduction in protists.
      ::在原生者中描述性生殖和性生殖。