Anna Neena George
Biological diversity deals with the degree of nature’s variety in the biosphere. This variety can be observed at three levels – genetic diversity – the genetic variability within a species; the variety of species within a community, and the organization of species in an area into distinctive plant and animal communities.
In most science textbooks, a lesson on biodiversity more often than not begins with definitions and teachers too religiously follow this method of teaching. The textbook also deals with the number of species and goes on to talk about species that are rare, extinct, endemic, endangered, threatened, ex-situ or in-situ conservation, and hotspots of biodiversity. All these are new and high sounding terms. Students probably think, ‘Why do we have to learn about so many plants and animals?’, ‘Why learn so many new terms?’, ‘Are these important for exams’? This approach to teaching biodiversity gives a totally theoretical idea about this very important field, turning it into something that is devoid of any relationship to real life. The students may certainly memorize all these facts and still remain ignorant about the biodiversity existing around them. The fact that we owe the variety of food that we eat to biodiversity is never touched upon in a way that would impact the students.
The two main ideas to be presented are: biodiversity is found everywhere and biodiversity makes life on earth possible. The objective is to create awareness about the bounty of biodiversity on earth which students are not conscious of and to impress upon them the responsibility to use it judiciously, conserve it for future generations to ensure life on earth.
Nature has the innate ability to rejuvenate and sustain life on earth and biodiversity is the key element which aids nature to do it. The study of biodiversity reveals these secrets of nature to the students rather than a few definitions.
Knowing biodiversity
The extreme emphasis on definitions and textbook-based information has made observation-based learning and knowledge generation unreliable. Biodiversity is something that can be seen around and experienced by every human being. Unfortunately, it is taught like any abstract concept.
Biodiversity is a multi-layered concept that can be dealt with at different levels. All the levels cannot be done together. Each level needs to be linked to the students’ real life experience. Compared to other topics, biodiversity can be seen easily. What should the strategy be to take students from one level to another?
First level:
• Biodiversity related to daily life: food, clothing, shelter.
• Biodiversity in the surroundings: home, garden, school.
Since biodiversity is all around us, students can be made conscious of their surroundings before they are exposed to the theoretical details. They need to appreciate that the very principle of nature is to maintain diversity in all living things. Simple activities will help them understand this expression from the textbook: ‘the variety and richness of all the plant and animal species at different scales in space, locally, in a region’. So many animals help us to make our food delicious and complete. What would life be like if there were no milk, no curd, no ice cream, no milk shake? Doesn’t that sound terrible to many of us? Some of us can’t imagine food without fish, chicken, and eggs. Do they all come from the same animal? No, certainly not. Hence, the diversity in animals gives us variety in our food. Is there only one type of cow, fish, chicken or are there several types? Why are there several types? This leads the students to find out about the types of animals that we depend on. This explains the idea of Species diversity. When they see the variety that nature has provided, they learn to appreciate and develop a strong intent to preserve it. Do animals and plants give us only food? Certainly not. They provide us with clothing, shelter, fuel, and medicines.
While explaining genetic diversity, teachers can pose the following questions to the class: what would happen if there was no rice and only wheat was available? What if one variety of rice/wheat vanished? What if one type of vegetable becomes extinct? And so on. This compels the students to find that a variety of rice, wheat, and vegetables exists. They find the diversity within a species! This leads to the conclusion that biodiversity allows us to have variety in our food and makes it balanced. Why has nature provided so much variety in rice or wheat or other plants? Students will realize that it ensures the continuation of the specie and also provides food for those who depend on it thereby keeping the ecosystem alive. Thus, they will understand the expression, ‘the genetic variability within a species’ and ‘variety of species within a community’.
Ecosystem and biodiversity
Second level
• Why does the earth need such a large variety of living organisms?
• Do the same type of animals, plants, birds, fishes exist all over the earth?
The ecosystem is a community of organisms and their physical environment as an ecological unit.
The type of animals and plants found in a particular place depends on rainfall, vegetation, climate, i.e., the geography of the place. The earth has varied geographical regions. Hence, the type of animals and plants found in different regions are different. This can be seen in one’s own surroundings. On investigation, it can be seen that the variety of organisms (animals and plants) found near a marshy place, in the paddy field, in a farm, on a mountain slope, near the river/pond of any town/city/village will be different. This can be explored physically. However, facts about different regions of the world can be gathered from books, or the Internet. This brings in the idea of Ecosystem diversity: desert, grassland, tropical, rain forest ecosystems to name a few. The biodiversity in an ecosystem ensures the sustenance of all the organisms with regard to food, reproduction and shelter, unique to each organism.
When the specific interdependence in an ecosystem is understood, then the extreme need for biodiversity becomes clear. All ecosystems have alternatives to sustain the foodweb. The alternatives in an ecosystem represent the biodiversity of a place. The
more options available to an organism, the more the chances of its survival. Thus, the interdependence of biodiversity and ecosystems and conservation can be established.
The pictures of the different birds and bees show that they have specific plants on which they feed. The interdependence is of mutual benefit. This ensures the survival of the ecosystem. There should be food and favourable surroundings to reproduce and nurture.
One look at the food webs of rain forest, desert tells a huge story. It shows species diversity within an ecosystem. The interdependence shows how it will sustain. Thus children will understand ‘variety of species within a community’, i.e., species diversity.
This gives the students a better picture of biodiversity as the essential element of sustaining life on earth by maintaining all ecosystems in all adverse conditions.
BOX 1: In the home or garden
Activity 1
Over the period of one week ask students to keep track of the different ants and spiders found in their house or in the kitchen garden and record the information in the following manner.
Insect | Location | Size | Colour |
Black ant | Kitchen | Small | Black |
Red ant | Garden | Big | Red |
Activity 2
Ask students to collect flowers (not from the garden) from a demarcated area. They can also collect different dry leaves from the same area. They can then make a collage using the flowers and dry leaves.
BOX 2: Investigation-based
Activity 1
Ask children to observe organisms around a flowering plant in the classroom/lab/home, for a week. They can also observe the different types of insects and birds visiting the plant. Ask them to note down their findings in a tabular column as shown here)
Insects/birds | Number | Size | Colour |
Small flies | 10 | Smaller than mosquito | Black |
Tiny bird | 2 | Smaller than sparrow | Green |
Activity 2
Students can spend half a day under adult supervision near a marsh or a pond.
They can observe organisms living in the pond and around the pond. They can also note the organisms that visit the pond occasionally. They can note the different plants found near the pond.
Plants/trees/grass | Size | Location | With flowers Y/N | Number |
Animals/birds/insects | Size | Location | Number |
Students can then make a presentation in their class based on their observations.
BOX 3: Outdoor trips
Activity 1
Children can visit a farm and interview a farmer about seeds.
They can then make a seed bank of different species: rice, chillies, wheat, pulses, oilseeds, vegetables, fruits, spices.
They can identify the seeds which are not in use. They can also learn whether they are grown locally and whether they are procured from other places.
Students can then exhibit their seed banks in their school.
Activity 2
Students can be taken to visit a fish market and asked to interview a fish vendor.
They can then make a poster showing all the fish and marine animals they saw in the fish market.
Conservation
Students can join a local conservation organization and interact with any local environment enthusiast. They can also take part in any local biodiversity documentation carried out by the organization.
They can be asked to upload their contribution on the website of the organization or on their school website.
The author is Associate Professor at GVM’s Dr. Dada Vaidya College of Education, Ponda, Goa. She can be reached at aneena2007@gmail.com.