| Learning Aims: | |||||||||||||||||
Subjects: Biology, physics and technology |
|||||||||||||||||
| Materials: | |||||||||||||||||
|
Calculator Tape measures Thermometer Hygrometer pH meter Light meter Quadrants (1 m2 or 0.25 m2) |
|||||||||||||||||
| Suggestions for use: | |||||||||||||||||
|
Introduce the topic: Humans are dependent upon plant life. Plants provide fuel, food, clothing, paper, shelter and yield important medicinal compounds. The International Union for Conservation of Nature and Natural resources (IUCN) report a combined total of 35,319 endangered plant species. Human impact has been the main cause of the rapid destruction of unique ecosystems, thus threatening plant species. Exercise 1 To learn relevant ecological terminology, such as: ecosystem, habitat, abiotic factors, species, population, community, density, endemic organism and adaptation. To consider conservation of endangered plant species The students will be asked to explore a local ecosystem and to select an endangered plant species for their field study. This inquiry-based activity will take place in the field, aiming to stimulate students’ interest to raise and investigate relevant scientific questions and connect learning with everyday life and human interest. A class of 20-30 students can be organized by the teacher in 4-6 teams, each team consisting of 5 students. There are many examples of local ecosystems that can be investigated—a pond, a school garden, a forest, an estuary and a grassland. Each team of students can suggest and inquire about a specific plant, which is present in the selected ecosystem. At the end of the field-work the students must search the web in order to find information so that they can write a short passage about the ecosystem under investigation highlighting and/or introducing relevant ecological terminology, such as, ecosystem, habitat, abiotic factor, species, population, community, density, endemic organism, adaptation. For example in Cyprus, the Athalassa National Park can be the selected ecosystem. As an example, a short passage follows introducing a Cypriot ecosystem: The Cyprus National Park of Athalassa (ecosystem) is the result of afforestation (deliberate planting in an area, which had not recently been a forest land). Thyme is indigenous species in Cyprus, very common to rocky slopes (habitat), disturbed ground and occasionally on sand dunes, in shrub lands and forests. It grows on all types of soils (abiotic factor), as it is a low-demand plant and prevents soil erosion. Thyme has xerophytic (drought-resistant) adaptations. Thyme has been well known since ancient times as a good source of nectar for honey bees, and for its aromatic and medicinal properties. “Thyme is a source of food for bees” (Aristotle Historia animalium). Shepherds also used it as fuel when making the local goat cheese. Such was the demand for thyme that there was a class of traders called “throumpopoulides” (sellers of thyme). A Cypriot amateur beekeeper has kept bee hives in his garden for the last three years, but he has not been able to increase their number. Cyprus has had very little rainfall and it faces desertification. The bee hives have not produced swarms and two beehives have perished. Human impact on the environment has been severe. The bee keeper observed that the number/ population of thyme plants in the Athalassa Park has been declining. It could be that thyme plants are stressed out. The following questions 1 and 2 can be used to assess student knowledge of the relevant ecological terminology. 1. Match relevant terms to the descriptions given. (A) Ecosystem or (B) Habitat ...................... is a specific area in a given time that consists of all the living organisms that interact with each other and the abiotic environment. A specific area where a living organism lives is called a ................................................. (C) Population or (D) community A group of individuals in a species is a …………………………………. All organisms in a habitat are described as a ……………………………. Numbers or (D) density (E) Numbers or (F) Density Population size refers to the ……………. in a population. Population ……………. refers to numbers in a given area or volume. 2. State the abiotic factors that may affect an organism in an ecosystem. Possible student answers include the following: pH, temperature, light intensity, moisture, slope, wind, minerals in the soil ………….. Based on the results of any similar evaluation, the teacher will then design activities or classroom discussion for clarifying or introducing the relevant terms, so that students will have clear understanding and orientation for their activities and tasks. Exercise 2 To estimate the density of an endangered plant species in a named ecosystem The following activity can be used to teach students how to estimate the density of a specific plant that is present in an ecosystem relative to a named abiotic factor such as temperature. The teacher needs to explain to the students that scientists many times cannot possibly count every organism in a population. However, scientists can estimate the size of a population. Students need to learn how to collect data by taking random samples. This activity can first take place in the field without the students knowing the full practical details of the methodology. The students are asked to inquire about how a named abiotic factor may affect the density of the named plant that they have selected. The correct methodology can be provided to the students at the end of their investigation in order to make comparisons and even correct their own designed methodology. The full practical details of random sampling including apparatus to estimate the density of a specific endangered plant in an ecosystem in relation to an abiotic factor, such as, temperature is provided below. Methodology of random sampling used to estimate the density of thyme plants that are present in a named ecosystem relative to a named abiotic factor that affects plant density.
Explain to the students why are these measurements needed. The students need to consider the limitations of their experiment. The teacher will explain to the students that limitations in an experimental investigation are factors that they cannot control, no matter what they do.
Exercise 3: Organization and representation of data In order to teach how to record and present data in a table and graph format, the students are asked to record and present their data in a table. The correct format of the table is given below. The table below is given to the students, once they have designed their own table. Of course, the approach should take into consideration students’ prior educational level and their abilities, knowledge and skills. TABLE OF RESULTS
|