SUBMITTED TO, RIYAZ SIR NATURAL SCIENCE MMTC VILAKKUDI

SUBMITTED BY,

SREELEKSHMI.S 1ST YEAR B.Ed. NATURAL SCIENCE MMTC VILAKKUDI

Collection and preservation of specimens

EDU-05.9: PEDAGOGIC CONTENT KNOWLEDGE ANALYSISNATURAL SCIENCE. UNIT 4-RESOURCES IN TEACHNG AND LEARNING OF NATURAL SCIENCE

ONLINE ASSIGNMENT

INTRODUCTION At elementary level, the child gains knowledge of scientific concepts by experience and observation but in higher classes they need more knowledge, therefore learning resources play a vital role in the process of learning. We all know that text books were the most widely used learning resource for science teaching for a long time; but in the present era, there has been a vast growth in each and every field and therefore the curriculum of science is reframed and restructured. With the explosion of new knowledge, new concepts and theories have emerged in science. These can be transacted in an effective manner with the help of appropriate learning resources. The child, members of the community and different resources available in immediate environment can be utilized as effective learning resources. Out of all available resources, a competent science teacher is expected to have the ability to identify appropriate learning resource for a specific content. The purpose and role of teaching and learning resources doesn't only consist of making the educational process more attractive and interesting, but also of the development

of different

skills

and the adoption

encouraging active

learning,

of desirable values and attitudes in

students. In order to achieve the aforementioned goals, it is extremely important to clearly define the conditions and methods of utilising teaching and learning resources in the teaching and learning process. Collecting plant and animal specimens is essential for scientific studies and conservation. Specimen collection from the same location or region can provide accurate details of historic and current biodiversity including potential trends diversity. Allows changes over time in morphology, physiology, anatomy to be detected .Preserved plant specimens provide us with important information about plant diversity and distribution, in a relatively permanent and verifiable form that serves as evidence of a plant's existence in time and space. If these specimens are properly preserved and maintained, they can last for well over 200 years. Researching the collections of insects provides important information that develops knowledge about ecology, human health and crops. Well-kept records aid the researcher in identifying whether there are differences in an observed specimen because of damages, treatments or deterioration.

COLLECTION AND PRESSERVATION OF SPECIMENS Natural Science Collections provide a valuable resource for helping us to understand the world in which we live. Apart from being hugely popular with the public, natural history collections play a vital role in our understanding of biodiversity, evolution, population genetics and the environmental impacts of climate change, pesticide use and so on. This is because historical collections provide base-line data against which modern observations can be compared and to produce predictive models. The

most

fundamental

role

of

natural

history

collections

is

safeguarding type specimens. These are preserved specimens of the individuals that were used to describe and name a species, providing the basis for taxonomy. Every plant, fungus and animal we see in our garden has a scientific name that comes from such a description and each new proposed species needs to be compared to the preserved types of other similar organisms in order to ensure that it is in fact different to anything already described. Collection of biological specimens provides a necessary foundation for effective conservation and wildlife management policy and is integral to rigorous and interdisciplinary biodiversity science A good science teacher makes provision for pupils to see and handle materials at the right time. Effective teaching stimulates a spirit of inquiry and interest in pupils and arouses in them desire to solve problems and to achieve results. Objects, specimens and models offer exceptional opportunities to the resourceful science teacher. In fact it is very doubtful whether effective science teaching can be achieved without the liberal usage of these visual aids. Specimen is a sample or a part of an object – foe example a piece of coal, a piece of marble, the skin of a bird, a leaf, or a piece of mineral. Depending upon how it is used in teaching, a thing may be an object or a specimen. Actual monarch butterfly if it were used by a biology teacher to represent all butterflies would be a specimen .Specimen is excellent visual aids for science teaching but they are not quite as valuable as an object.

COLLECTION OF SPECIMENS

A scientific collection is a collection of items that are preserved, catalogued, and managed for the purpose of scientific study. Scientific collections dealing specifically with organisms plants, fungi, animals, insects and their remains, may also be called natural history collections or biological collections. The latter may contain either living stocks or preserved repositories of biodiversity specimens and materials. Scientific collections hold a tangible portion of the cumulative evidence base in such

field as biology(especially taxonomy and evolutionary biology), geology, and archaeology.

They

may

be

stored

and

managed

by governments,

educational

institutions

(e.g. colleges and universities), private organizations (including museums), or individuals. Prominent uses of scientific collections include the systematic description and identification of biological species, the study and prediction of long-term historical trends (including impacts of climate change), the dating and analysis of historical objects (e.g. via wood samples and ice cores with annual rings), and the maintenance of teaching resources. Plant collecting is the acquisition of plant specimens for the purposes of research, cultivation, or as a hobby. Plant specimens may be kept alive, but are more commonly dried and pressed to preserve the quality of the specimen. Plant collecting is an ancient practice with records of a Chinese botanist collecting roses over 5000 years ago. Herbaria are collections of preserved plants samples and their associated data for scientific purposes. The largest herbarium in the world exists at the Museum National d'Histoire Naturelle, in Paris, France. Plant samples in herbaria typically include a reference sheet with information about the plant and details of collection. This detailed and organized system of filing provides horticulturist and other researchers alike with a way to find information about a certain plant, and a way to add new information to an existing plant sample file. The collection of live plant specimens from the wild, sometimes referred to as plant hunting, is an activity that has occurred for centuries. A zoological specimen is an animal or part of an animal preserved for scientific use. Various uses are: to verify the identity of a (species), to allow study, increase public knowledge of zoology. Zoological specimens are extremely diverse. Examples are bird and mammal

study skins, mounted specimens, skeletal material, casts, pinned insects, dried material, animals preserved in liquid preservatives, and microscope slides. Natural history museums are repositories of zoological specimens.

Information from collections is used for: 

identifying rare species, and finding where they live



identifying weeds, and exotic plants and animals



commercial products, such as medicine made from plants



Deciding on conservation areas.

Types of collections 

Plants are kept in collections called herbaria. New Zealand has 16 herbaria, including one of fungi, and one showing plant diseases. Among them, they have more than 1,300,000 plant specimens.



Animal collections include collections of insects and freshwater fish. New species from the sea are still being found and added to marine animal collections.



Fossils are also kept in collections, because they are records of life in the past. They include shells, bones, plant fossils and microscopic fossils.

PRESERVATION OF SPECIMENS

Specimen preservation means “long-term preservation of organisms either plant or animal in the best possible condition. So that it can be accessed in future as reference collection for scientific purposes” Many chemical methods are used to preserve both vertebrate and invertebrate specimens for maintenances purposes. The specimen is prepared by “fixing” it, achieved by injecting it with chemicals that stop the deterioration and decay process (known as “autolysis”). The most common fixative is formaldehyde, or a formaldehyde and water solution known as formalin. Plant specimens are collected in the field, pressed flat between newspapers, and dried in a plant press.

At the time of collection, the collector takes notes in a field-log about the possible identity of the plant, where and when it was collected, habitat characteristics including soil type and other plant associates, flower color and scent, size and habit of the plant, and any other pertinent information that may not be obtainable from the resultant specimen. After drying, the plant is mounted on acid-free paper with a label providing the name and classification of the plant as well as all collection data. After mounting, herbarium specimens are stored in special cabinets and are filed in order by taxonomic group and then by geographic origin

.

Preserved plant specimens provide us with important information about plant diversity and distribution, in a relatively permanent and verifiable form that serves as evidence of a plant’s existence in time and space. If these specimens are properly preserved and maintained, they can last for well over 200 years. In a time where we are experiencing rapid habitat loss, herbaria provide important repositories for these sorts of data, and ensure their availability for future research Animal specimens are usually preserved in jars containing preservative solutions. Plants

and animals are sometimes preserved as dry specimens. Insects are preserved in insect boxes after collecting, killing and pinning. Large animals (e.g. birds and mammals) are stuffed and preserved in

.

containers We can preserve specimen in a jar by using a hypodermic needle and luer -lock syringe to inject your specimen with an initial solution (either humectant fluid, which you can make from

ethyl or isopropyl alcohol or ethanol and propylene glycol, or formalin) and allow it to soak in a jar full of the initial solution for several weeks.

Taxidermy is an art to preserve the biological specimens with their skin in dry form which is quite expensive. The present study involves a technique which needs less time and cheapest chemicals as sodium chloride, thymol, 5% formol saline; simple items like needle, thread, flexible wires and containers.

CONCLUSION Collection and preservation of specimens as a resource for teaching and learning of natural science plays a vital role in making students aware about plants and animals around them. Rather than text books this will help to make them more interesting toward science and increase curiosity and motivate them to study more about nature and its diversity.