Topic: Species diversity

Target group

High school / technical school student

Core curriculum

General requirements

V. Reasoning and applying the acquired knowledge to solving biological problems. Pupil:

1) interpret information and explain causal relationships between processes and phenomena, formulate conclusions.

Specific requirements

XI. Biodiversity, its threats and protection. Pupil:

1) presents types of biodiversity: genetic, species and ecosystem.

General aim of education

Students explain the importance of species diversity.

Key competences

• communication in foreign languages;

• digital competence;

• learning to learn.

Criteria for success
The student will learn:

• exchange examples of regions characterized by large and small species diversity;

• describe selected factors determining diversity of species;

• explain the meaning of endemics and relics for species diversity and exchange examples of them.

Methods/techniques

• expository

  • talk.

• activating

  • discussion.

• programmed

  • with computer;

  • with e‑textbook.

• practical

  • exercices concerned.

Forms of work

• individual activity;

• activity in pairs;

• activity in groups;

• collective activity.

Teaching aids

• e‑textbook;

• notebook and crayons/felt‑tip pens;

• interactive whiteboard, tablets/computers.

Lesson plan overview

Before classes

• The teacher instructs students to familiarize themselves with the content of the abstract. In addition, he asks his students to team up in teams in such a way that members of one team live close to the same park or other tree‑lined area. The task of each group is to visit the chosen place and evaluate its species diversity, and then to prepare a multimedia presentation according to the teacher's instructions..

Introduction

• The teacher gives the topic, the goals of the lesson in a language understandable for the student, and the criteria of success.

Realization

• Volunteers or persons indicated by the teacher discuss the following issues:

  • the concept of species diversity;

  • endemic species;

  • relict species;

  • the process of speciation;

  • geographical diversity of species diversity on the Earth.

• The teacher initiates a discussion devoted to factors affecting species diversity and human influence on the extinction of certain species. Using the brainstorming method, students give specific examples of factors related to climate, terrain and human activity, and then assess their impact on species diversity.

• The individual teams present the effects of working together on the class forum, discussing the diversity of selected places. The lecturer and other students give them feedback on the strengths of the materials presented and the elements that need to be further developed.

• Students perform exercises and commands. The teacher checks and supplements the answers, providing students with the necessary information. Provides feedback..

• Students use the interactive board to organize their knowledge.

Summary

• The teacher briefly presents the most important issues discussed in class. He answers the additional questions of the proteges and explains all their doubts. Students complete notes.

Homework

• Listen to the abstract recording at home. Pay attention to pronunciation, accent and intonation. Learn to pronounce the words learned during the lesson.

• Where can we expect more endemic species: in Malta or in New Caledonia? Answer justify.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Species diversity

According to the averaged calculations, our planet is inhabited by approx. 8.7 million of eukaryotic organisms species, including approx. 400 thousand of plant species and approx. 8 million of animal species, as well as 8–10 million of prokaryotes.

Species diversity is specified in relation to a specific ecosystem or area. It is expressed by the total number of species occurring in this area, often provided per unit of area. The bigger this number is, the higher species diversity of the analysed area. The precise assessment of the number of species living in a given ecosystem is not possible.

For sure, the number of species of vertebrates can be estimated most precisely and easily. It is estimated that there are approx. 60 thousand species of vertebrates, half of which is fish species, almost 15 thousand – amphibians and reptiles, 10 thousand – birds, and mammals amount to only 5.5 thousand. The estimation of species diversity of insects (which are the most numerous taxon) constitutes the basic difficulty in precise assessment of the number of invertebrate species. The establishment of species diversity of bacteria or fungi is similarly difficult due to the size of the group.

The species diversity of land ecosystems is assessed on the basis of quantity of species of vascular plants in these ecosystems. Vascular plants are very well analysed, and the estimation of their number in a given area is easier than in case of other kingdoms. These organisms do not relocate and in most cases, they grow into sizes which make it possible to notice them without specialist apparatus.

There are both common and rare species among the species living in a given area. Rare species are described as endemic species which means organisms the range of which is very limited, they are unique for a given area, and they are not present in natural environment in any other location. The examples of endemic species are as follows: Galapagos penguins living in Galapagos Islands, kangaroos from Australia, jaguars from Middle and South America, lemurs living in Madagascar and Comoros Islands. Plant endemic species are for example Echium species from Macaronesia, Australian Eucalyptus, Sequoia from North America and African Welwitschia. The number of endemic species in a given area is related to species diversity – in locations where there are many endemic species, also other species are numerous and diversified.

Endemic species usually occur in oceanic islands, especially those located in big distance from a continent, and in high mountains. Endemic species may be created due to the separation of a given population by a geographic barrier. As the effect of isolation (after some time, usually long time), the populations differ to such extent that they cannot cross, which means that they become separate species. The process of creating new species is called speciation.

The number of endemic species in Poland is small. Endemic species are present in Tatra Mountains, Pienin Mountains and Sudetes, both in the territory of Poland and neighbouring countries (Slovakia and Czech Republic). Among plant species the following ones are endemic: Delphinium oxysepalum, Saxifraga wahlenbergii, and among animals these are: Carpathian newt and Tatra pine vole. There is no agreement in scientific environment whether the Tatra plants and animals listed above are separate species.

The species which currently have small territory range which is a remnant of significantly wider range are called relicts. In the Polish flora, the postglacial relicts include, among others, dwarf birch (Betula nana), Dryas octopetala, downy willow (Salix lapponum), Linnaea borealis, snow saxifrage (Micranthes nivalis) – plants typical for mountainous areas. Relict species are relics of former geological epochs.

The following factors have significant influence on species diversity: climate, availability of water, and topographic relief. Vegetation zones on the Earth depend on climate of a given area, and that is why their arrangement, similarly to climatic zones, is based on parallels. It is due to the fact that plants need a specific temperature and humidity for their growth. The biggest number of species live in the zones with wet and warm climate, and the smallest number in a very dry and cold environment.

The lowest species diversity of plants is observed in the areas such as: hot deserts and polar deserts, and semi‑deserts, tundra, steppes. A huge richness of species is characteristic of tropical rainforest and in ecosystems of mountains. In Poland, the area with the biggest species diversity is Tatra Mountains.

The second factor, following the climate, which has an impact on species diversity of biosphere is topographical relief. There are significantly more species in the mountains than on the plains. It is connected with the diversity of conditions present in these areas, e.g. with huge variability of temperatures, humidity, exposure to sunlight and wind, as well as with the types of subsoil typical for specific parts of mountains.

Species diversity on islands depends on their surface area, distance from mainland and the diversity of habitat conditions. The bigger the island is, the more species live there. What is more, the further the island is located from the mainland, the more endemic species can be found there.

• Both common and rare species constitute the species diversity of an ecosystem.

• Species diversity of a given area depends on many environmental factors, such as: climate, topographical relief, availability of water, type of soil.