初一生物论文500字（主要写动物）急

草履虫

草履虫是一种身体很小，圆筒形的原生动物，它只有一个细胞构成，是单细胞动物，雌雄同体。最常见的是尾草履虫。体长只有180—280微米。它和变形虫的寿命最短，以小时来计算，寿命时间为一昼夜左右。因为它身体形状从平面角度看上去像一只倒放的草鞋底而叫做草履虫

草履虫 paramecium 草履虫草履虫全身由一个细胞组成，体内有一对成型的细胞核，即营养核（大核）和生殖核（小核），进行分裂生殖时，小核分裂成新的大核和小核，旧的大核退化消失，故称其为真核生物。其身体表面包着一层表膜，除了维持草履虫的体型外，还负责内外气体交换，吸收水里的氧气，排出二氧化碳。膜上密密地长着近万根纤毛，靠纤毛的划动在水中旋转运动。它身体的一侧有一条凹入的小沟，叫“口沟”，相当于草履虫的“嘴巴”。口沟内的密长的纤毛摆动时，能把水里的细菌和有机碎屑作为食物摆进口沟，再进入草履虫体内，供其慢慢消化吸收。残渣由一个叫肛门点的小孔排出。 草履虫的生殖方式是分裂生殖。

细胞器及功能

草履虫细胞器的功能分工如下： 口沟：取食 据估计，一只草履虫每小时大约能形成60个食物泡，每个食物泡中大约含有30个细菌，因此，一只草履虫每天大约能吞食43000个细菌，它对污水有一定的净化作用。 表膜：氧的摄入，二氧化碳的排出都通过表膜 大核：营养代谢 小核：生殖作用 食物泡：食物泡是草履虫进行胞吞作用产生的,进入细胞后将与初级溶酶体融合形成次级溶酶体。 伸缩泡及收集管：收集代谢废物和多余的水，并排出体外 胞肛：排出不能消化的食物残渣 纤毛：辅助运动，草履虫靠纤毛的摆动在水中旋转前进 注意：草履虫中没有线粒体，叶绿体，中心体以及细胞壁。

[编辑本段]生态环境中的作用

草履虫属于动物界中最原始、最低等的原生动物。它喜欢生活在有机物含量较多的稻田、水沟或水不大流动的池塘中，以细菌和单细胞藻类为食。据估计，一只草履虫每小时大约能形成60个食物泡，每个食物泡中大约含有30个细菌，因此，一只草履虫每天大约能吞食43200个细菌，它对污水有一定的净化作用。

草履虫的种类

草履虫的分类：草履虫属于纤毛纲，膜口目，草履虫科。世界上已经报导过的草履虫有22种 草履虫结构我国常见种至少有下述几种。 1．大草履虫 又叫尾草履虫，长180—280微米，后端圆锥形，锥顶角度约45至60度。两个伸缩泡均有收集管。有小核一个，致密型，椭圆形。生活在有机质较多的死水或缓流中。 2．双小核草履虫 长80－170微米，形似尾草履虫，但后部较前部更宽，后端锥形，顶角近90度。有伸缩泡两个，收集管较短。有两个小核，很小，泡型。生活环境和尾草履虫相同。 3．多小核草履虫 长180—310微米，形似尾草履虫，有时有三个伸缩泡。小核泡型，有3—12个。生活环境和尾草履虫相同。 4．绿草履虫 体长80—150微米。细胞质内有绿藻共生，在见光处培养后通体呈绿色。小核一个，致密型。生活在清水池塘。

养殖与纯化

养殖

草履虫是鱼幼苗生长必需的一种饵料。但其不易被发现，也很难捕捉，因此为补充其不足，应当人工饲养。其方法是： 取干稻草切成小段，直接浸泡于水中或煮后浸泡，用稻草浸出液作培养液。然后将浸过的稻草与水放进玻璃容器内，水占2/3以上，置于光照充足的地方。再到腐殖质丰富的地方去取种源，那里的水质应比捞红虫的坑塘水质清。舀回一桶水，取部分水体装入无色透明的小瓶内，对阳光细心观察，可见有白色小点悬浮于水中。如果看不见小白点，应用力搅动桶水，再取中央部位的水装入小瓶，对准光线看有无小白点。如见有小白点悬浮水中飘忽不定，可将此水倒如培养液中。将温度控制在22℃~28℃之间，1个星期后便可发现有草履虫的幼体了。喂其煮熟的牛肉汁，大约0.5小时后分裂。

纯化

取普通多孔水浴锅一只，在锅内安装一只暖棒（恒温加热器，温度范围16～32℃），加水、通电、调温至25℃；同时安放50ml、1000ml烧杯各一只，内盛自来水2/3左右。将野外采集的草履虫液在水浴锅中放置一周左右，取上层含有草履虫的澄清液数滴移入50mL小烧杯内培养。一周后，小烧杯内水面与杯壁相接处，就会有较多的草履虫，用细滴管沿杯壁取数滴移入1000ml烧杯中培养。经过1～5次转移培养，就能获得较纯的草履虫，即使有少量其他原生动物，也会被迅速繁殖起来的草履虫种群所抑制。若大量需用草履虫，可在塑料桶内安装暖棒调温至25℃，从上述培养液中取数滴于桶中培养，2周后即能繁殖出大量草履虫。 草履虫观察的注意事项 在显微镜下观察，最好在载玻片上放适量的棉花纤维，这样可以避免草履虫乱动。

生活环境

喜生活在有机物丰富的池塘、水沟、洼地等。大多数草履虫是吞噬式营养，但绿草履虫是例外，体内含共生绿藻，这种绿藻可利用动物体排泄的含氮废物作为无机盐的来源，通过植物式光合作用制造有机物生存。

一、什么是水产生态养殖

养鱼的朋友都知道，我们养鱼的鱼塘是一个复杂的生态系统。水面以上有阳光，空气；塘基上有陆生植物；水是有鱼、有各种水生植物、昆虫、蚤类、藻类、真菌、细菌、病毒、以及有机物和无机盐。池底有淤泥，同样也生长得上述生物及有机物和无机盐。它们之间存在着相养、相生、相帮、相克等极其复杂的关系，生态养殖就是合理利用它们之间的相生、相养、相帮、相克的关系，生产我们所需要的水产品。合理利用它们之间的关系，不管是从经济效益还是社全效益和环境效益，都能达到一个最好的结果，这就是生态养殖。

二、什么是绿色无公害水产品

首先，养殖基地必须经过认证，其中最主要的是大气、土壤、水质必须符合《农产品安全质量----水产品产地环境要求》国家标准和《无公害食品淡水养殖用水水质》农业部标准的要求；其次，必须按照无公害水产品的生产技术操作规程进行养殖，从苗种放养到饲料、肥料、渔药等一切投入品的使用，再到产品的捕捞、贮运、质检、包袋、上市的各个环节均需符合相关标准或规范的要求；第三，产品必须经过政府指定的权威质检机构的抽检、完全合格并颁证后方能进入市场销售。

三、水产生态养殖有何意义

1，环境效益：传统的养殖模式，不但用水量大，而且施用的大剂量的国家违禁药品，如硫酸铜、孔雀石绿、敌百虫、呋喃类药等，随着大量换水，对坏境造成很大的破坏。同时对于鱼塘底质也造成难以估量的损害，使鱼塘生态环境遭到极大的破坏，恶性病源微生物大量增殖。生产的水产品通过食物链的扩散，不但对人的健康造成了损害，对环境的破环也是巨大的。

2，社会效益：随着人民生活水平的提高，人们环保意思的加强，人们更加注重食品安全性，加上我国加入WTO，水产品要进入国际市场，必须达到别国的食品安全标准，因此，为了国人的身体健康，和中国水产品出口的高额利润，必须执行生态养殖。

3，经济效益：传统的养殖模式，已经造成了鱼池微生物菌群严重失衡，病原微生物巨增，抗药性增强，养鱼户不得不加大药物用量，结果鱼病治不好，鱼体受伤，产量锐减，品质下降，成本增加，泛塘事件屡屡发生。这就是我们大通湖及周边地区常规鱼养殖户放弃养鱼，鱼塘种棉花怪现像发生的主要原因。湖北养鱼户率先应用了微生物制剂生态养殖法，已产生了可喜的成绩，他们生产的草鱼以低于我地每公斤1元的绝对优势，占领着湖南岳阳鲜鱼市场和其它湖南部份鲜鱼市场。在黄鳝养殖上也是用药泡着，隔三差五施药，严重影响了黄鳝的生长和产品品质，使养殖成本居高不下。更有甚者，越冬黄鳝成箱成箱的死亡，给我们不施执生态养殖敲响了警钟。我们养殖户必须改变生产观念！走出传统养殖模式的怪圈。

四，倡导生态养殖的可行性

随着我国水产科学的进步，已经为生态养殖研究出了系统的技术，制定了科学的标准，同时也研究出了适合生态养殖的高效、低残留、低剂量的水产用药，特别中成药和中药提取物，和有益微生物制剂天意EM原露，深圳希科安公司生产的动物强壮剂饲料添加剂-活力素。更是我们施执生态养殖有了足够的保障。广东的亩产草鱼过吨半的事例，同样也可以作为生态养殖的可行性的佐证。

五、怎样实行生态养殖

生态养殖包含的范畴很宽，它主要有如下几种。(一)人工生态环境养殖法。(二)多品种立体养殖法。(三)开放式流水或微流水养殖法。(四)全封闭循环水工厂化养殖法。(五)水产品与农作物共生互利养殖法。(六)使用微生物制剂养殖法。因为篇幅的限制，我这里不能作一一的阐述，就着重对使用微生物制剂法加以说明，如果对前五种方法感兴趣的朋友，请到我部咨询。 什么是微生物制剂养殖法：近10年来，微生物活菌制剂逐渐在水产养殖中得到应用推广，这给无公害健康养殖生产提供了有力的保障。目前较多使用的产品有光合细菌制剂，芽胞杆菌、乳酸杆菌制剂，天意EM原露等。他们能分解水体中的残饵、鱼粪等有机质，降低水中的氨氮含量，使养殖水体变清洁，从而改善了环境；他们能改善养殖对象的胃肠道内环境，增强食欲，促进生长，提高饲料报酬；他们还能强化养殖对象的免疫功能，提高免疫力，增强抗病能力；还能强化有益菌群，防止和减少细菌性疾病的发生与蔓延。

I. What is the aquatic eco-farming

Fish friends are aware that we fish ponds is a complex ecosystem. The sun above the water, air; Tong have land-based plants; water is a fish, a variety of aquatic plants, insects, fleas, algae, fungi, bacteria, viruses, and organic and inorganic salts. Mud bottom there is also growing these organisms and organic and inorganic salts. Between them there is a phase dependent, with students such as grams of extremely complex relations, ecological farming is the rational use of their students with dependents,compared the relationship between grams, production of aquatic products we need. Rational use of the relations between them, whether from economic or social benefits and environmental benefits the whole, to achieve the best results, this is the eco-culture.

Second, what is the green pollution-free aquatic

First of all, the breeding base to be certified, of which the most important thing is the atmosphere, soil, water quality must be consistent with "the quality safety of agricultural products ---- environmental requirements of aquatic origin," National Institute of Standards and "pollution-free water for the water quality of freshwater aquaculture products," the Ministry of Agriculture standards requirements; Second, pollution-free aquatic products in accordance with the rules of production technologies for breeding, from fry stocking to feed, fertilizer, Drugs, such as the use of all inputs, to fishing products, storage and transportation, quality inspection, bag listed to comply with all aspects of the relevant standards or norms; the third, the product must go through the authority designated by the Government of the sampling inspection agencies, fully qualified and licensing in order to enter the market after the sale.

Third, what is the significance of aquatic eco-farming

1, environmental benefits: the traditional mode of farming, not only large quantities of water, and the application of large doses of countries banned substances, such as copper, malachite green, trichlorfon, furans and other drugs, with a large number of the water, on the bad habitat caused great damage. Substrate for the fish ponds at the same time also caused incalculable damage to fish ponds in the ecological environment has been greatly damaged, a large number of malignant proliferation of pathogenic micro-organisms. Produced by the proliferation of aquatic products through the food chain, not only on human health damage, environmental destruction is enormous.

2, social benefits: With the improvement of people's lives, it is meant to strengthen environmental protection, people pay more attention to food safety, coupled with China's accession to the WTO, aquatic products to enter the international market, other countries must meet food safety standards, therefore, To the health of the people, and China, the export of aquatic products of high profits, they must be the implementation of eco-farming.

3, cost-effective: the traditional mode of farming, has caused a serious imbalance in Yuchih microbial flora, pathogenic microorganisms by macrophages, enhanced resistance, the fish farmers had to increase the drug dosage, the results of fish diseases body injuries, sharp drop in output, decline in quality, cost increase has occurred frequently Tong Pan. This is our Chase Lake and the surrounding areas of conventional fish farmers to give up fish, fish ponds is strange to produce much cotton as the main reason for the occurrence. Hubei mariculturists microbial agents take the lead in the application of eco-farming method, has produced gratifying results, they produced less than I in grass carp to 1 yuan per kilogram of absolute superiority, occupied the fish market in Hunan Yueyang in Hunan Province and other parts of fresh fish market. In the rice field eel is also a drug culture on the bubble, andapplication, Monopterus seriously affected the growth and product quality, so that the cost of high culture. Even worse, the winter Monopterus boxes into the death of me, to us they are no wake-up call ecological farming. Fish farmers must change our production concept! Out of the traditional model of the cycle of breeding.

Fourth, promote the feasibility of eco-farming

With the progress of China's Aquatic Sciences, has been developed for the ecological farming system technology, has developed standards for science, but also for eco-culture has developed a highly efficient and low-residue, low-dose administration of fisheries, particularly in medicine and Chinese extract, and beneficial microbial preparations reveal the original EM Providence, Shenzhenproduced tonic animal feed additives - Huolisu. Shi Zhi and it is eco-farming has been adequately protected. Guangdong's per-mu yield of grass carp have been a half tons of examples, the same can also be used as the feasibility of eco-culture of evidence.

Fifth, how to implement eco-farming

Ecological farming includes a wide scope, it has the following several major. (A) the ecological environment of artificial breeding method. (B) three-dimensional multi-species breeding method. (C) open-water or water micro-culture method. (D) closed the factory farm method of circulating water. (V) aquatic symbiotic and mutually beneficial crop breeding method. (Vi) the use of microbial culture preparation method. Because of space limitations, I can not be here on the 11, we focus on the use of microbial preparations to illustrate this method, if the methods of the former five friends interested in, please go to the Department of advice I have. What is the breeding method microbial agents: the past 10 years, gradually Microorganisms in aquaculture are applied to promote the health of this culture to the pollution-free production provided strong protection. At present, more products are used preparations of photosynthetic bacteria, Bacillus, Lactobacillus preparations, such as an act of God reveal the original EM. They can break down残饵water, fish manure and other organic matter, reduce the ammonia content in water, so that culture change clean water, thereby improving the environment; they can object to improve the breeding environment of the gastrointestinal tract, enhance the appetite, promote growth and improve feed remuneration; they can strengthen the immune function of the target culture and enhance immunity, enhanced disease resistance; can strengthen the beneficial bacteria to prevent and reduce the occurrence of bacterial diseases and the spread.