Topic: Principles for the classification of organisms

Author: Elżbieta Szedzianis

Target group

5th grade student of elementary school.

Core curriculum

II. Diversity of life.

1. Classification of organisms. Student:

1) justifies the need for classification of organisms and provides principles for a biological classification system.

Lesson objectives

Students explain why organisms are classified.

The criteria for success

• you will explain why organisms are classified;

• you will specify the name of the species and the genus to which you belong.

Key competences

• communication in the mother tongue;

• communication in foreign languages;

• mathematical competence and basis competences in science and technology; 

• digital competence;

• learning to learn;

• social and civic competences.

Methods/forms of work

Working with text, talk, workshop method.

Individual activity and activity in groups.

Teaching aids

• abstract;

• interactive whiteboard or traditional blackboard;

• tablets/computers;

• bags with various items;

• a large sheet of paper (for a poster with difficult words);

• marker pens;

• grey paper;

• cards with images of animals;

• table tents.

Before classes

The teacher puts various items into bags.

Lesson plan overview

Introduction

1. The teacher asks the students to form groups of several. Each group receives a bag with various items. The students' task is to divide the items into groups and to define the criteria for their division (similarity, purpose, etc.). Students write the criteria down on sheets of paper and place them on each group of items. Then, the students present results of their work. During the presentation they explain how they understand the term “criterion”.

2. The teacher displays the definition of the classification criterion and asks the selected students to explain the concept in their own words. The teacher explains that the word “classification” can be replaced by the word “grouping”. The teacher asks why objects are ordered, for what purpose books in the library are arranged alphabetically according to the authors' names, and why we keep cutlery in the kitchen and clothes in the wardrobe.

3. The teacher introduces the students to the subject of the classes by saying that the number and variety of organisms is enormous: the number of insect species alone is estimated at about 30 million, and the number of all species is close to 100 million, with scientists managing to describe less than 2 million so far. In view of such a large number of organisms, it was necessary to classify them. During the classes, the students will learn the methods of classification. The teacher specifies the subject and the objective of the lesson and the criteria for success. The teacher informs that difficult and new terms, which students will learn during the classes, will be written down on a poster (a large sheet of paper) hung next to the board. Each student may write an incomprehensible word on it.

Realization

1. The teacher displays an interactive illustration of the classification of the mute swan. The teacher discusses the specified groups (Swans, Anatidae, Anseriformes, Birds, Chordates, Animals) and gives examples of organisms belonging to these groups. The teacher asks the students to read the systematic categories (the teacher can compare them to shelves or drawers).

2. Each group receives sheets of grey paper, pens and small cards with images of the following animals:

• mute swan;

• black swan;

• mallard;

• tufted duck;

• horned screamer (the word “Anseriformes” must be placed on the card of this species),

• ostrich;

• penguin;

• fish;

• rabbit;

• butterfly;

• snail.

The teacher encourages the students to find a way to group animals and to name the groups by their systematic categories (specify the genus, family, order, etc.). The teacher observes the work of the groups, listens to their discussions, gives guidelines and answers questions. If any of the groups encounters problems when performing the task, it can use an interactive illustration showing the classification of the mute swan.

3. The teacher asks the students why they have classified their organisms. The teacher asks the students to define the term “classification” and think about the areas of life in which this word is used and what it means in particular areas.

4. The teacher says that he/she will classify himself/herself and all students in the classroom. The teacher asks students to note down the classification in their notebooks. The teacher writes down the specific name of man in Polish and Latin on the board. The teacher asks if anyone else besides him/her and the students in the classroom belongs to the genre of Humans.

5. The teacher explains that the specific name usually consists of two words: a noun and an adjective. The teacher gives examples of the specific names and the generic names. Students write these names down in their notebooks.

Summary

The teacher presents a poster with difficult terms. After reading each term, the students assess whether the term is sufficiently clear to them using coloured table tents (green, yellow or red). If one of the terms is assessed with yellow or red cards, students discuss them in groups using abstract dictionary or other sources.

Homework

Students do interactive exercise no. 1 and perform the following task:

“Find out which species, except for Homo sapiens, is included in the genus Homo.
Is this species currently present on Earth?”.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Principles for the classification of organisms

It can be assumed that the earliest division of organisms used by humans was the one based on utility, e.g. edible and inedible. Later on, they were divided according to many other criteria.

The science involved in describing, naming and classifying organisms is called systematics. The criterion used nowadays to classify organisms is their structure and mutual relationship.

The basic category in the classification of organisms is species, i.e. a collection of all individuals having similar features and capable of producing fertile offspring. Swedish naturalist Carl Linnaeus described about 10 thousand plant species and about 6 thousand animal species. He gave the species he described binomial names in Latin, which at that time was the international language of science. To date, scientists around the world have been using Latin names for species. This ensures that any organism can be identified regardless of its local name.

The name of each species (species name or scientific name) consists of a generic name (which is a noun) and a specific name which is and an adjective (rarely a noun) which, together, identify the species. Species names (scientific names) are Ursus arctos, i.e. brown bear and Ursus maritimus, polar bear. Both bears belong to one genus – Ursus, i.e. bear, however to two different species.

The classification systems used today, just like Linnaeus’ system, are hierarchical systems. They bring organisms together in higher and higher taxonomic (systematic) categories, i.e. taxons, starting from the lowest category, which is species. Taxonomic categories are groups of organisms that are related to each other, distinguished from each other by one or more features. Combining organisms into taxonomic categories according to their common features allows for organisation of knowledge about them.

The highest taxon (taxonomic category) is the kingdom. In case of animals, it is divided into phyla and phyla into smaller categories – classes. The class consists of orders, which include families. Families have genera and these consist of species.

The plant classification categories have slightly different names than the animal classification categories, but the rules for organising the organisms are the same. In the kingdom of plants, instead of the name phylum – is used name division. In addition to the basic systematic categories, there are also so‑called auxiliary categories. Usually they have prefixes over- (e.g. superfamily), or sub- (e.g. subspecies). There are also the ones that have a separate name, e.g. variety, tribe, form.

• Science called systematics deals with classification of organisms.

• Species name (scientific name) of an organism consists of two parts. The first one is the generic name, and both of them together - are the species name.

• The layout (system) of taxonomic categories is hierarchical. The lowest taxonomic category is species. Further categories in case of animals are, respectively, the genus, the family, the order, the class, the phylum and the kingdom.