Name: leaf traits and tree id with a key
Uploaded: 2023-04-30T06:37:07.000Z
Duration: 12 min 6 s
Channel: JoVE
Description: Leaf traits can help students identify trees with a dichotomous key. A dichotomous key is a nature ID tool that works by choosing between two characteristics at each step. The word dichotomous comes from two Greek words that mean "to divide into two parts."

K12 Standards

Alabama Course of Study Science

9-12

Environmental Science

Unity and Diversity

9-12.EVS.2.3.b

tree-identification-how-to-use-a-dichotomous-key

Tree Identification: How To Use a Dichotomous Key

1. 一组10个未知样品的鉴定
使用二分检索表（表1）鉴定10个未知的叶片样本（图6-15）。
<ol>
	<li>选取一片叶子，从检索表的第1项开始，逐项回答每个问题。</li>
	<li>选择最能描述该叶片特征的陈述。</li>
	<li>右侧栏列出的是树种名称，或下一个需要参考的陈述编号。</li>
	<li>继续此过程，直至检索表中列出该叶样来源的树种名称，并填写所提供的空白表格（表2）。</li>
</ol>
2. 野外调查
从5棵树上采集叶片样本，使用树木野外指南正确鉴定树种，并在数据表上记录（表3）。
<ol>
	<li>选择一棵需要鉴定的树木。</li>
	<li>从该树木采集一片具有代表性的叶片样本。</li>
	<li>使用普通胶水将其固定在标本纸上。</li>
	<li>观察并记录叶片在枝条上的排列方式，为互生或对生。</li>
	<li>在标本纸和数据记录表上记录该信息。</li>
	<li>测量树木胸径（dbh），单位为英寸。
	<ol>
		<li>测量方法为：在距地面现有高度4½英尺处测量树干周长，再通过公式 d = C/Π 计算直径。将周长和直径数值记录在数据记录表上。</li>
	</ol>
	</li>
	<li>在数据记录表上注明树木附近最近的土地用途类型：独栋住宅区、多户住宅区、小型商业区、工业/大型商业区，或公园/其他空置土地。</li>
	<li>对另外4棵树木重复执行步骤2.1至2.7，共采集5份叶片样本。</li>
	<li>使用所选的树木野外鉴定指南，鉴定叶片样本，并将物种名称记录在数据记录表上。</li>
</ol>
3. 国家树木效益计算器
使用该软件可以计算行道树带来的效益，包括树木在暴雨管理、财产价值、能源效率和碳封存方面的年度效益。
<ol>
	<li>打开美国农业部林务局开发的面向教育的 iTree 软件工具，网址为 http://www.treebenefits.com/calculator/，这意味着 iTree 工具属于公共领域。</li>
	<li>使用国家树木效益计算器（图 16）以及收集到的树木数据，计算每棵树的环境效益。</li>
	<li>记录计算结果。</li>
</ol>
<img alt="对生叶序示意图，植物学研究，叶片形态分析。" src="/files/ftp_upload/10070/10070fig8.jpg" data-altupdatedat="1761830439000" data-alt="图 8">
<img alt="白色背景上的单片叶片标本的互生叶排列示意图。" src="/files/ftp_upload/10070/10070fig9.jpg" data-altupdatedat="1761830439000" data-alt="图 9">
<img alt="对生叶序示意图；植物学学习辅助图示，展示叶片排列模式与结构。" src="/files/ftp_upload/10070/10070fig10.jpg" data-altupdatedat="1761830439000" data-alt="图10">
<img alt="叶片形态学研究，对生叶序，植物标本展示。" src="/files/ftp_upload/10070/10070fig11.jpg" data-altupdatedat="1761830439000" data-alt="图11">
<img alt="叶片形态学研究，白色背景上的心形叶片，羽状脉序，植物解剖学分析。" src="/files/ftp_upload/10070/10070fig12.jpg" data-altupdatedat="1761830439000" data-alt="图12">
<img alt="叶片形态、互生排列、植物生物学研究、植物学、叶脉模式分析。" src="/files/ftp_upload/10070/10070fig13.jpg" data-altupdatedat="1761830439000" data-alt="图13">
<img alt="互生叶序，压制药材标本，植物学研究，植物形态学。" src="/files/ftp_upload/10070/10070fig14.jpg" data-altupdatedat="1761830439000" data-alt="图14">
<img alt="植物标本，未知植物物种，腊叶标本，分类学研究。" src="/files/ftp_upload/10070/10070fig15.jpg" data-altupdatedat="1761830439000" data-alt="图15">
<img alt="叶片形态图，显示白色背景上的互生排列，用于植物学研究。" src="/files/ftp_upload/10070/10070fig16.jpg" data-altupdatedat="1761830439000" data-alt="图16">
<img alt="标本馆标本分析，纸上的植物样品，植物学研究，未知物种鉴定。" src="/files/ftp_upload/10070/10070fig17.jpg" data-altupdatedat="1761830439000" data-alt="图17">
图6-15. 未知叶片样本。
<img alt="国家树木效益计算器网页；输入树种、大小、位置以进行生态系统效益分析。" src="/files/ftp_upload/10070/10070fig18.jpg" data-altupdatedat="1761830439000" data-alt="图16"> 
图16. 国家树木效益计算器。
<table align="center" border="1" cellpadding="0" cellspacing="0" fo:keep-together.within-page="always">
	<tbody>
		<tr>
			<td>1</td>
			<td colspan="4">叶片呈针状或鳞片状吗？ 
			叶片是阔叶吗？</td>
			<td>第2行 
			第3行</td>
		</tr>
		<tr>
			<td>2</td>
			<td colspan="4">叶片呈鳞片状吗？ 
			叶片呈针状吗？</td>
			<td>红柏 
			苏格兰松</td>
		</tr>
		<tr>
			<td>3</td>
			<td colspan="4">叶片是单叶吗？ 
			叶片是复叶吗？</td>
			<td>第4行 
			第5行</td>
		</tr>
		<tr>
			<td>4</td>
			<td colspan="4">叶片有裂吗？ 
			叶片无裂吗？</td>
			<td>第6行 
			第7行</td>
		</tr>
		<tr>
			<td>5</td>
			<td colspan="4">叶片为一次复叶吗？ 
			叶片为二次复叶吗？</td>
			<td>绿梣树 
			洋槐</td>
		</tr>
		<tr>
			<td>6</td>
			<td colspan="4">叶片为羽状裂吗？ 
			叶片为掌状裂吗？</td>
			<td>栓皮栎 
			第8行</td>
		</tr>
		<tr>
			<td>7</td>
			<td colspan="4">叶片边缘有锯齿吗？ 
			叶片边缘无锯齿吗？</td>
			<td>第9行 
			紫荆</td>
		</tr>
		<tr>
			<td>8</td>
			<td colspan="4">叶片是否具有3–5个深裂且叶序对生？ 
			叶片是否具有3–5个浅裂且叶序互生？</td>
			<td>银槭 
			悬铃木</td>
		</tr>
		<tr>
			<td>9</td>
			<td colspan="4">叶片边缘是否具有双重锯齿、呈椭圆形且基部不对称？ 
			叶片边缘是否为单锯齿？</td>
			<td>美国榆 
			杨树</td>
		</tr>
	</tbody>
</table>
表1. 树木鉴定二分检索表。
<table cellpadding="0" cellspacing="0" fo:keep-together.within-page="always">
	<tbody>
		<tr>
			<td>未知样品</td>
			<td colspan="4">物种</td>
		</tr>
		<tr>
			<td>1</td>
			<td colspan="4"></td>
		</tr>
		<tr>
			<td>2</td>
			<td colspan="4"></td>
		</tr>
		<tr>
			<td>3</td>
			<td colspan="4"></td>
		</tr>
		<tr>
			<td>4</td>
			<td colspan="4"></td>
		</tr>
		<tr>
			<td>5</td>
			<td colspan="4"></td>
		</tr>
		<tr>
			<td>6</td>
			<td colspan="4"></td>
		</tr>
		<tr>
			<td>7</td>
			<td colspan="4"></td>
		</tr>
		<tr>
			<td>8</td>
			<td colspan="4"></td>
		</tr>
		<tr>
			<td>9</td>
			<td colspan="4"></td>
		</tr>
		<tr>
			<td>10</td>
			<td colspan="4"></td>
		</tr>
	</tbody>
</table>
表2. 用于填写每份未知叶片样本树种的空白表格。
<table align="center" border="1" cellpadding="0" cellspacing="0" fo:keep-together.within-page="always">
	<tbody>
		<tr>
			<td>树木样本编号</td>
			<td>叶序（对生、互生或轮生）</td>
			<td>距地面4½英尺处周长（英寸）</td>
			<td>距地面4½英尺处直径（英寸）*计算值</td>
			<td>土地用途</td>
			<td>物种</td>
			<td>备注</td>
		</tr>
		<tr>
			<td>1</td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>2</td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>3</td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>4</td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>5</td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>
表3. 用于填写叶序、周长、胸径、土地利用类型、物种及备注的空白数据表。

了解树木为社区带来的益处至关重要。将这些益处转化为货币价值或生态系统服务价值，有助于具体理解树木在生态系统中所发挥的确切作用。树木对健康、经济和环境都具有重要意义，一旦认识到这一点，就可以开始讨论保护树木并提升其效益的方法。随着树木的生长和年龄增长，其带来的益处也随之增加。这为保护成熟树木提供了充分理由（图17）。
这些信息可用于确定在社区中种植哪些树木更具效益，也可供城市管理人员用于指导基础设施建设的决策。例如 关于新建建筑施工所需种植的树木数量/类型的政策）。利益相关方也可自行决定在其房产范围内种植树木的数量和种类，以帮助降低能源费用（例如 学校、企业、政府机构 
<img alt="森林中一棵具有庞大根系的古树，用于说明根系在养分吸收研究中的作用。" src="/files/ftp_upload/10070/10070fig19.jpg" data-altupdatedat="...

树木鉴定：如何使用二分检索表

来源：Margaret Workman 和 Kimberly Frye 实验室 - 德保罗大学
二分检索表是一种用于鉴定自然界中物品（例如树叶）的工具。该方法基于在两个特征之间进行选择的理念。“二分”一词源自两个希腊语单词，意为“分成两部分”。在用于树叶鉴定的二分检索表中，每一对短语描述了树叶的不同特征。其中仅有一个短语适用于待鉴定的树叶。正确的短语将引导至下一对短语，或直接指出该树叶所属树木的名称。在野外调查中，借助树木野外指南和iTree国家树木效益计算器，有助于识别树木，从而展示树木在环境效益方面的重要性，例如雨水管理、提升财产价值、提高能源效率、改善空气质量以及碳封存。

表4 包含了正确鉴定出的叶片，用于鉴定一组10种未知物种。
野外调查的结果将根据所采集的样本而有所不同。美国芝加哥地区（邮编60031）发现的树木代表性结果见表5。
使用树木效益计算器的结果见表6。该计算器可估算单棵路边树木所提供的生态与经济效益。&#160;输入实地调查数据（包括邮政编码、树种、直径和土地用途）后，即可查看每棵树所提供的环境与经济效益。&#160;
<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>未知样本</td>
			<td colspan="4">物种</td>
		</tr>
		<tr>
			<td>1</td>
			<td colspan="4">美国榆树</td>
		</tr>
		...

来源：德保罗大学 Margaret Workman 与 Kimberly Frye 实验室  
二分检索表是一种用于鉴定自然界中生物或物体的工具，例如……

二歧式检索表常用于科学领域中对自然界中的物种进行鉴定，包括树木。使用者通过逐一回答成对的选择题，最终确定样本的种类。在二分检索表中，问题以成对的短语或问题形式提出，其中只有一项是正确的。正确的选项会引导至下一个问题或短语，如此逐步推进，最终经过若干步骤后，实现对目标物品的鉴定。通过二叉检索表进行树木鉴定时，使用者需研究叶片特征及叶序，并依次选择成对描述短语，直至确定该叶片所属的树种。本视频将演示二歧检索表的结构、使用方法，以及用于树木鉴定的二歧检索表中所采用的一些叶片特征。叶片是不同树种的重要特征，常用于树木的鉴定。在鉴定树木样本时，可考虑叶片的形状、排列方式、叶缘形态以及其他多种特征。阔叶树在美国很常见，其特点是具有宽阔叶面的叶片，可暴露大面积用于光合作用。大多数阔叶树为落叶树，会在秋季落叶。美国的第二大主要树种是常绿树。这类树木具有针状或鳞片状的叶片，通常全年保留在树上。针状叶片的光合作用表面积较小，且具有较厚的蜡质涂层以防止水分流失，因此针叶常绿树非常适合生长在需依靠保水来维持生存的地区。叶片形状与树种的进化历史密切相关，且根据生态系统的需求，叶片需要在最大化吸收阳光的同时，尽量减少热量吸收和水分流失。总体而言，叶片形状是一种常用于在二分检索表中对阔叶植物进行分类的性状。叶片的形状可分为心形、三角形、披针形、卵形或倒卵形。此外还有其他形状的叶片，但以上几种最为常见。叶片在小枝上的排列方式是树木鉴别特征中的另一个重要特征。对生叶是指在节上成对出现的叶片，通常相邻的叶层呈直角排列，以尽量减少重叠。互生叶是最常见的排列方式，叶片交错分布，不直接相对，常沿小枝呈螺旋状排列。轮生排列则是指在单个节上着生三片或更多叶片。叶片的边缘，即叶缘，也可能提供有助于鉴定的特征。叶缘可能是光滑的，也可能具有突起、锯齿或波状结构。呈波浪状或凹凸不平的边缘称为圆形或波状（sinuate）。这种特征同样可能与环境条件有关。在较冷的气候中，本地树木的叶片往往具有更大且更多的锯齿。对于阔叶树，叶片可分为单叶和复叶。单叶具有一个叶片、一个叶柄（或称“叶轴”）以及位于叶柄基部的一个芽。复叶则具有两个或更多的小叶，并在叶柄基部有一个芽。进一步地，一回羽状复叶具有一条主叶柄，小叶排列在主叶柄的两侧；二回羽状复叶具有一条主叶柄，且在主叶柄两侧排列有次级叶柄。这一特征可用于区分叶片与小叶：若某结构与茎相连处无芽，则为小叶而非叶片。现在我们已经熟悉了一些常见树木和叶片的特征，以及用于树木鉴定的一些分类方法，接下来让我们逐步了解如何使用检索表。在尝试鉴定叶片样本之前，必须首先熟悉检索表中所检查的性状及其分类。检索表中的第一个问题是询问叶片标本是针状或鳞片状，还是阔叶状。前两种归类为常绿植物，后一种为落叶植物。如果答案是“针状或鳞片状”，则进入检索表的第2行；如果是“阔叶状”，则进入第3行。第2行涉及针状或鳞片状的叶片，并询问哪一种最能描述该样本。针状叶片的表面积很小，具有较厚的蜡质层，以防止过度失水。鳞片状叶片的表面积也较窄，但由许多细小的独立鳞片组成。如果叶片呈鳞片状，检索表判定该标本为红雪松；如果叶片呈针状，则检索表判定该标本为欧洲赤松。问题3询问叶片是单叶还是复叶。单叶是指每个叶柄或茎上仅有一个小叶，且叶柄基部有一个芽。复叶是指具有两个或以上小叶、一个叶柄以及在基部有芽的叶片。如果叶片为单叶，则进入第4行；若为复叶，则进入第5行。第四个问题是判断叶片为分裂叶还是不分裂叶。分裂叶是指具有突起部分从而形成特定叶形的叶片。不分裂叶则具有连续一致的叶缘。若叶片为分裂叶，检索表指示进入第6行；若为不分裂叶，则应接着查阅第7行。第5行承接第3个问题，询问叶片是单次羽状复叶还是二次羽状复叶。单次羽状复叶在叶柄两侧以羽状排列着两个或更多小叶；二次羽状复叶则具有一条主叶柄，其两侧再分出次级叶柄。此为最终判定问题，其中单次羽状复叶对应植物为绿梣（Green Ash），二次羽状复叶对应植物为洋槐（Honeylocust）。问题6涉及裂叶阔叶。叶片是羽状裂还是掌状裂？羽状裂是指裂片均连接到一条中轴或主脉上。相反，掌状裂的叶片，其裂片均从一个点呈辐射状伸出。若为羽状裂叶片，则该叶片属于夏栎；若为掌状裂叶片，则检索表进入第8行。在第7行，关键特征询问叶片样本的边缘是否有锯齿。锯齿分为连续状和锯齿状，而光滑叶片的边缘则无任何锯齿或尖突。具有锯齿的样本进入问题9，无锯齿的则被归类为紫荆叶。问题8询问叶样品是具有3-5个深裂片和对生叶序，还是具有3-5个浅裂片和互生叶序。深裂片指裂口深入叶表面，对生叶序指叶片在节上成对出现。浅裂片指裂口较浅，未深入叶表面，互生叶序指叶片交错排列，不直接相对。具有深裂片和对生叶序的为银枫（Silver Maple），而具有浅裂片和互生叶序的为悬铃木（Sycamore）。最后，问题9询问叶缘是否具有双重锯齿、椭圆形且基部不对称，或者相反，叶缘为单锯齿。若符合前者特征，则该样本鉴定为美国榆树；若叶片具有单锯齿叶缘，则属于杨树。现在，利用图示的叶片并结合二歧检索表来练习物种鉴定。在查阅检索表并了解相关特征描述后，即可进行树木的野外鉴定。首先，选择一棵待鉴定的树木，从中采集一片具有代表性的叶片样本，并使用胶水将其固定在腊叶标本纸上。接下来，观察叶片在茎上的排列方式为互生还是对生，并将此特征记录在标本采集表上。通过测量树木在距地面4.5英尺处的胸径周长（单位为英寸），计算其直径，并记录周长和直径数值。记录距离树木最近的土地利用类型：住宅区、小型商业区、工业区、公园或空地。利用二歧检索表鉴定叶片样本，并在标本纸上记录树木的物种名称。树木鉴定具有多种实际应用，而二分检索表是用于快速鉴定的有用且实用的工具。树木识别是了解特定树木或树种在社区环境中所提供效益的重要第一步。利用树木识别数据以及国家树木效益计算器，科学家和城市规划者可以借助树木数据来制定有关建筑、基础设施或种植策略的决策，以最大化对健康和环境的益处，并减少能源消耗。二分检索表常用于鉴定多种不同类型的生物。例如，可用于鉴定从毒蛇物种、柑橘树害虫昆虫，到水生植物种类等各种生物。该技术可使不熟悉标本的使用者在野外或实验室环境中，通过逐步比对来鉴定生物种类。通过检索表识别树木或其害虫的能力在病虫害防治中可能极为有用。例如，亚洲长角天牛正日益成为美国林地中的常见害虫。利用昆虫分类检索表，可将此类害虫与其他本地长角天牛区分开来，并识别出已发现该害虫的林地中易受侵害的树种。这反过来有助于遏制这种高度入侵性害虫的扩散。您刚刚观看了 JoVE 关于使用二分检索表鉴定树木的简介视频。现在您应该理解二分检索表的工作原理，以及如何应用二分检索表进行树木鉴定。感谢观看！

Education

教育

JoVE Science Education

Environmental Sciences

环境科学

树识别: 如何使用二分法的关键

leaf traits and tree id with a key

Leaf traits can help students identify trees with a dichotomous key. A dichotomous key is a nature ID tool that works by choosing between two characteristics at each step. The word dichotomous comes from two Greek words that mean &quot;to divide into two parts.&quot;

Leaf Traits and Tree ID With a Key

tree identification: how to use a dichotomous key

Leaf traits can help students identify trees with a dichotomous key. A dichotomous key is a nature ID tool that works by choosing between two characteristics at each step. The word dichotomous comes from two Greek words that mean "to divide into two...

tree survey: point-centered quarter sampling method

tree-survey-point-centered-quarter-sampling-method

Forest Tree Density Sampling Method

Forest tree density sampling can be done with the point-centered quarter method. This field method helps measure the density, frequency, and coverage of tree species in a forest. It also helps estimate how many individual trees are present, how often a tree species appears, how common it is compared with other trees, and the size of the trees. The point-centered quarter method is useful because it is more efficient than standard plot analysis. In fixed-area plot sampling, only a small part of...

using gis to investigate urban forestry

GIS Mapping of Urban Trees and Parks

GIS helps map urban forests and the many trees found in cities. Urban forests include urban parks, street trees, landscaped boulevards, public gardens, river and coastal promenades, greenways, river corridors, wetlands, nature preserves, natural areas, shelterbelts of trees, and even working trees at industrial brownfield sites. These spaces are more than decoration. They are part of city infrastructure and support human life in ways similar to food, housing, and other public utilities. Urban...

proton exchange membrane fuel cells

Hydrogen Power from PEM Fuel Cells

Proton exchange membrane fuel cells use hydrogen gas to make electric current. They are part of the search for cleaner energy sources that can help replace non-renewable fuels used for electricity, transportation, industry, and homes. The United States now uses about 97.5 quadrillion BTUs of energy each year, and about 90% still comes from non-renewable sources. Hydrogen is one possible renewable energy carrier. It is abundant in the universe, but on Earth it is found in compounds such as...

biofuels: producing ethanol from cellulosic material

biofuels-producing-ethanol-from-cellulosic-material

Ethanol Production from Plant Waste

Ethanol can be produced from plant waste such as corn stalks, leaves, and grasses. In this lab, cellulosic material is used as the feedstock, which means it is the starting plant material for the reaction. The process shows how biomass can be turned into a fuel product. The material is first pretreated by grinding and heating it. It is then digested with enzymes, which break the material down further. Next, yeast ferments the sample and ethanol forms during the reaction. Ethanol production is...

testing for genetically modified foods

Detecting GMO DNA in Food Samples

Food DNA can be tested for genetically modified material by using PCR and gel electrophoresis. This experiment shows how food DNA is identified so students can better understand the science behind GMOs and the concerns linked to health and environmental safety. Polymerase chain reaction, or PCR, is used to amplify the DNA from food samples. Amplifying the DNA makes it possible to test for the presence of genetically modified DNA. The method gives a clear way to compare test foods with known...

turbidity and total solids in surface water

turbidity-and-total-solids-in-surface-water

Measuring Water Clarity with Secchi Disks

Turbidity and total solids are two ways to measure water clarity in surface waters. Turbidity is an indirect measure. It shows how much light can pass through the water. Total solids are measured directly by weight and show the amount of solid particles suspended in the water. High turbidity and high total solids can come from soil erosion, waste discharge, runoff, or changes in ecological communities. Algal growth and the abundance of benthic organisms can also disturb sediment and mix it...

dissolved oxygen in surface water

How Low Oxygen Creates Dead Zones

Dissolved oxygen in surface water helps support life in lakes, rivers, and oceans. Fish, such as bluegill and bass, need it to survive. Decomposer species also depend on it to recycle biogeochemical materials in the ecosystem. When dissolved oxygen drops below normal levels, water quality declines and organisms begin to die. Low oxygen can happen during eutrophication, when excess nutrients trigger a fast algal bloom. The bloom forms dense mats at the surface and blocks two key oxygen sources:...

nutrients in aquatic ecosystems

How Nutrients Drive Algal Blooms

Nitrogen and phosphorus are important nutrients in aquatic ecosystems. Water quality tests often monitor both because too much of either can create serious water quality problems. Nitrogen in water is usually measured as nitrate, written as NO3-. Nitrate dissolves in water and is easily taken up by photosynthesizers such as algae. Phosphorus is usually measured as phosphate, written as PO43-. Phosphate can be found dissolved in water, and it also binds strongly to sediment particles. When...

measuring tropospheric ozone

Tropospheric Ozone in Air and Smog

Tropospheric ozone is an air pollutant found in the lower atmosphere. It is a form of elemental oxygen, O3, made of three oxygen atoms in a highly reactive structure. In the troposphere, ozone contributes to photochemical smog and can harm people, plants, and materials. Ozone also exists in the stratosphere, about 10 to 50 km above Earth’s surface. There, it forms the ozone layer and helps block harmful UV rays from reaching the ground. Tropospheric ozone is different because it occurs near...

determination of nox in automobile exhaust using uv-vis spectroscopy

determination-of-nox-in-automobile-exhaust-using-uv-vis-spectroscopy

How Car Exhaust NOx Drives Smog Formation

Car exhaust releases nitrogen oxides, or NOx, that help drive smog formation in the lower atmosphere. In the troposphere, sunlight splits nitrogen dioxide (NO2) into nitric oxide (NO) and oxygen atoms. Those oxygen atoms then combine with O2 to make ozone (O3). Ozone can also react with NO to reform NO2 and O2, so this cycle does not create a net gain of ozone on its own. Problems begin when fossil fuel combustion adds extra NO, NO2, and volatile organic compounds (VOCs) to the air. Motor...

lead analysis of soil using atomic absorption spectroscopy

lead-analysis-of-soil-using-atomic-absorption-spectroscopy

Testing Soil for Lead Contamination

Lead contamination in soil can be measured with atomic absorption spectroscopy. Lead is a naturally occurring element in soil, usually at 10 to 50 ppm. But soil near old paint, gasoline use, or industrial pollution can contain much higher levels. In some urban areas, lead can reach 10,000 ppm. Lead stays in soil because it does not biodegrade. That makes it a long-term hazard. Children are at particular risk from lead exposure. Millions of children in the U.S. may contact soil that contains...

carbon and nitrogen analysis of environmental samples

carbon-and-nitrogen-analysis-of-environmental-samples

Measuring Carbon and Nitrogen in Soil

Carbon and nitrogen in soil can be measured by elemental analysis. Environmental samples such as soils are often studied for these two ecologically important elements. Scientists use these results to understand the elemental makeup of a material. This method uses flash combustion to analyze the sample. The sample is oxidized with a catalyst in a high-temperature chamber. The combustion products are then reduced to nitrogen gas (N2) and carbon dioxide (CO2). A thermal conductivity detector...

soil nutrient analysis: nitrogen, phosphorus, and potassium

soil-nutrient-analysis-nitrogen-phosphorus-and-potassium

Measuring Soil Fertility with NPK Tests

Soil fertility can be measured by testing the macronutrients nitrogen, phosphorus, and potassium. These three nutrients are major parts of soil fertilizer, and their levels help show how well soil can support plant growth. The experiment uses chemical extraction to pull each nutrient out of the soil and into a solution. Color-based reagents are then added to the extracted samples. The nutrients are analyzed by color and turbidity, which is the cloudiness of a solution, to estimate how much of...

analysis of earthworm populations in soil

analysis-of-earthworm-populations-in-soil

Mustard Soil Sampling for Earthworms

Earthworm populations can be sampled from soil with mustard. The mustard draws Lumbricus terrestris earthworms up from deeper soil layers. This method lets scientists collect data without disturbing the landscape or using toxic chemicals. After sampling, the earthworms are counted. The counts can then be used for data analysis and statistical testing. A bar graph and a student’s t-test help compare the results. Monitoring earthworm populations is important in environmental science. Many...

environmental science

该集合利用跨学科的方法来探索和评价环境系统, 题目包括土壤和水污染物、侵入物种、替代能源和林业。

Learn how a dichotomous key uses leaf traits to identify trees and why tree ID matters in field investigations and environmental benefits.

Leaf Traits and Tree ID With a Key | JoVE K12

Next Generation Science Standards

High School

Earth and Space Science

Earth and Human Activity

HS-ESS3-4

new-york-state-science-learning-standards

New York State Science Learning Standards

Life Science

Structure and Function

HS-LS1-3.

interdependent-relationships-in-ecosystems

Interdependent Relationships in Ecosystems

HS-LS2-2.

Earth and Space Sciences

Human Sustainability

HS-ESS3-1.

HS-ESS3-3.

HS-ESS3-4.

HS-ESS3-6.

Georgia Standards of Excellence

SEV4.

SEV4.a

Overview

Principles of Tree Identification Using a Dichotomous Key

Preparing to Use the Dichotomous Key

Field Investigation

Applications

Summary

What are Populations and Communities?

Populations are groups of individuals of the same species that inhabit a shared environment. Communities include multiple co-existing, interacting ...

Distribution and Dispersion

Ecology is the study of how organisms interact with their environment and with one another. An important aspect of ecology is understanding where species ...

Life Histories

Constrained by limited energy and resources, organisms must compromise between offspring quantity and parental investment. This trade-off is represented ...

Ecological Niches

All organisms have a position within an ecosystem. The complete set of living and nonliving factors&#x2014;including food resources, climate, and ...

Ecological Succession

Ecological succession is influenced by the processes of facilitation, inhibition, and toleration. Facilitation occurs when early successional species ...

What is an Ecosystem?

Overview

An ecosystem is the interaction between all abiotic and biotic factors in an environment and can be classified as terrestrial or aquatic. ...

3. Construct an explanation of how biotic and abiotic factors affect biodiversity and populations in ecosystems. Examples: Explain how factors such as biomass, reproductive strategies, succession, climate, and geography affect an organism's chances of surviving and reproducing through successive generations.

9-12.EVS.2.3

Keystone Species

Measures of species biodiversity, such as richness (i.e., the number of species present) and evenness (i.e., their relative abundance), describe an ...

What is Biodiversity?

Biodiversity describes the variety of living things at multiple organizational levels: genetic, species and ecosystem diversity. Species diversity ...

Threats to Biodiversity

There have been five major extinction events throughout geological history, resulting in the elimination of biodiversity, followed by a rebound of species ...

Analysis of Earthworm Populations in Soil

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University
Using mustard, Lumbricus terrestris earthworm populations can be sampled ...

water-quality-analysis-via-indicator-organisms

Water Quality Analysis via Indicator Organisms

Source: Laboratories of Dr. Ian Pepper and Dr. Charles Gerba -The University of Arizona
Demonstrating Author: Luisa Ikner
Water quality analysis monitors ...

What is Conservation Biology?

Conservation biology is a scientific field that focuses on the preservation of biodiversity in order to protect ecosystems while meeting the needs of the ...

Measuring Biodiversity

Diverse ecosystems are important for the health of the planet and our survival as humans; it is therefore incredibly important for us to understand and ...

Community Diversity

Populations do not live in isolation; thus, every population interacts with others in certain ways. These interactions give rise to a network of ...

a. Support a claim that biodiversity is a natural resource which fosters ecosystem resilience, including the role of keystone, invasive, native, endemic, and indicator species.

9-12.EVS.2.3.a

gis-software-hardware-and-sources-of-gis-data

GIS Software, Hardware, and Sources of GIS Data

A Geographic Information System (GIS) combines specialized software and hardware to effectively manage, analyze, and present spatial and related data. GIS ...

Manipulation and Analysis

GIS manipulation and analysis functions are vital for decision-making and planning. These activities range from data retrieval tasks, such as selecting ...

Using GIS to Investigate Urban Forestry

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University
Urban forests broadly include urban parks, street trees, landscaped ...

using-topographic-maps-to-generate-topographic-profiles

Using Topographic Maps to Generate Topographic Profiles

Source: Laboratory of Alan Lester - University of Colorado Boulder
Topographic maps are &#34;plan-view&#34; representations of Earth&#39;s ...

Tree Survey: Point-Centered Quarter Sampling Method

A number of methods are available for sampling forest communities. Point-centered quarter is one such method. It is used to gather information on the ...

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University
A dichotomous key is a tool that identifies items in nature, such as ...

Introduction to Microbial Ecology

Microbial ecology examines the complex web of interactions and diversity among microorganisms within various ecosystems. This field seeks to understand ...

Species Distribution and Biogeography

Simulating Colonization and Extinction on Islands
ExpandForm groups of three. One member of the group will simulate colonization by throwing balls into ...

Freshwater Microbial Ecology

Freshwater systems such as streams, rivers, and lakes exhibit distinct physical and biological characteristics that influence their microbial communities. ...

Soil Microbial Ecology

Soil microbial ecology is defined by highly diverse, spatially structured communities that drive nutrient cycling, organic matter turnover, and overall ...

b. Analyze and interpret data collected through geographic research and field investigations to describe Alabama's biodiversity by region. Examples: Use relief, topographic, and physiographic maps or information on rivers, forests, and watersheds to investigate species distributions and diversity.

Leaf Traits and Tree ID With a Key

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