![]() ![]() Of poroid and gilled fungi, the keys to these groups are first divided by an initial key into several smaller keys.Įventually, the key will lead you to a species name. Of a given couplet will have the same number or letter and will have the same indentation from the margin. Note that the two leads of a given couplet do not necessarily occupy two sequential lines. Given this key and a 175 pound, green-eyed male, the person would be identified as person G. Person weighs less than 200 pound s.Person G This imaginary key to seven people illustrates how dichotomous keys work:ģ. If the user makes the correct decision atĮach couplet, the destination (i.e., correct identity) will be reached. In the key, eachĭecision point is called a couplet and each alternative decision is called a lead. ![]() In the road), dichotomous keys are also a series of decision points (dichotomies) where the user must decide which of two directions best matches the specimen at hand. ![]() Using a map involves decisions to use one road or another (forks With fungi, the correct destination is the identity of the species in hand. If you've never used a dichotomous key,Īpproach it as you would a roadmap in the sense that a map and a key are devices to help guide you to a desiredĭestination. If you’re looking for some ready-made activities where students can practice using and writing a key, visit my TpT store.Apart from the initial shape key, the other keys follow a dichotomous style. It may take students a bit of practice to master the skill of using dichotomous keys but by providing structured, interactive opportunities to both use and make keys, they’ll soon grasp it. When creating a dichotomous key, encourage students to focus on attributes or characteristics they can observe (and not what they already know about something).Paired work when using or creating a key can promote good discussion.Remind students to always return to the start of the key when identifying something new.Encourage students not to rush and to read carefully – one wrong observation can lead to a completely different place in the key.Once keys have been created, have students try out each other’s to see how well they work. Students could create a key with the following examples: Give students the opportunity to create a key using a small number of objects or organsims (e.g. Check out this free ‘identify the candy’ activity on TechersPayTeachers where students identify the candy types using a key.Ĭlick to download this free key activity Create a key Whilst keys are most commonly used in the field of biology for identifying organisms, students can practice the concept of keys with a variety of objects. You may find it useful to use familiar examples in the first instance, before moving on to identifying unfamiliar objects/organisms. ![]() Introduce a simple dichotomous key for pupils to use. They then follow the corresponding path to the next set of statements until they reach an identification. The user must choose which statement in the pair best describes the object or organism. Dichotomous keys consist of a series of pairs of statements (couplets) or questions, each of which describes a characteristic of the object or organism being identified. Provide examples of dichotomous keys and discuss how they are structured. They should understand that that animals and plants are grouped according to their observable features. Before you startīefore you start, it’s important that students have been introduced to the concept of classification in science. This blog post looks at how to introduce and use dichotomous keys successfully in your science lessons with upper elementary or primary (Key Stage 2) children. They also develop critical thinking skills. By breaking down the characteristics of different species, students understand the process of identifying unknown animals and plants. Teaching dichotomous keys in science lessons can be a fun and engaging way to re-introduce students to the concept of taxonomy and identification. ![]()
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