Preserving plant specimens

Pressing and drying

        Techniques for pressing and drying specimens have been established for many years. There are minor variations in recommended methods, but they are essentially the same worldwide.The best specimens are plants that are pressed as soon as possible after collection, before wilting and shrivelling. Most plants may be kept in sealed containers such as plastic bags for up to a day if it is inconvenient to press immediately. However, some plants show such rapid wilting, particularly of the flowers, that such delays are best avoided. Flowers with a lot of nectar may go mouldy very quickly if excess nectar is not shaken off before pressing.Specimens are pressed flat and dried between sheets of absorbent blotters or semi-absorbent paper such as newspaper. Papers with a glossy surface should be avoided because they are not absorbent enough to aid drying. The plant should be carefully laid out between the drying sheets, as their form at this stage largely determines their ultimate appearance. The flowers should be spread out with the petals carefully arranged, wilted leaves should be straightened and unnecessary shoots of excessively twiggy shrubs may be cut away.Large flowers (e.g. Nymphaea) or inflorescences (e.g. Telopea) are best cut in half lengthways before pressing. Large and/or succulent fruit is often best preserved by cutting both longitudinal and transectional (from different fruit) sections from them and drying these. Care is necessary to ensure that the maximum amount of useful information s preserved.Sheets of thick, preferably smooth-sided, centre-corrugated cardboard (such as used in cardboard carton sides), placed between the drying folders will assist air circulation through the press. These are particularly necessary when using a forced circulation of warm air. If such cardboard is not available, additional sheets of newspaper or wooden board (e.g. plywood) may be used to absorb moisture from succulent specimens.When plants are uneven in thickness, e.g. where flowers are borne on thick twigs or arise from a thick bulbous base, sheets of spongy plastic foam (polyurethane or similar) about 1 cm thick, placed between the newspaper folders, help to distribute pressure evenly across the specimen. If foam sheets are not available, several thicknesses of folded newspaper may be used. Care must be taken to ensure 'damp spots' do not develop in the press. When using foam sheets it is advisable to circulate warm air around the press or change the drying papers more frequently.Specimens are best pressed with moderate pressure, preferably in an arrangement that will permit as free a circulation of air as possible. This can be achieved by strapping the pile together in a press, i.e. between frames made, for example, from sheets of heavy (non-bending) cardboard, hardboard, plywood, pegboard or, best of all, a lattice of wood or weldmesh (see picture). Supplies of suitable materials can usually be obtained from packaging and cardboard manufacturers, who will cut materials to suitable sizes, or from hardware or building suppliers. The press frames should be the same size as or a little larger thatn the drying paprs. Amateur collectors often press small numbers of specimens by placing books or other weights on the pile of specimens, but this is not recommended as specimens quickly go mouldy without air circulation.The papers should be checked for dampness and changed when necessary. As the number of changes required will vary with the original succulence/water content of the plants and with the weather conditions, no exact guide can be given. Most plants should dry in less than ten days. Foir the first few days the paper should be changed daily, but after that time the frequency of changes needed depends on conditions and relative humidity levels. In tropical and wet conditions daily changes will be necessary throughout the drying period, but in drier conditions the last one or two changes need only be given at intervals of three or four days. Used paper should be discarded, or thoroughly dried again before re-use.When in the field for an extended time, drying can be aided by placing the pressed plants in a warm, sunny position during the day. In reasonably dry climates, drying is aided by securing the presses to the roof rack of the vehicle whilst driving in dry daytime conditions. If available, a hot-air fan directing air around the press will assist drying. Drying cabinets with a forced circulation of warm air are used in large herbaria to shorten drying time and to lessen the need to change drying papers, but are not necessary for small quantities of specimens.A few species regularly turn black on drying, but in general, brownish or blackish colours in the completed specimens, or the growth of mould, indicate that drying was too slow, often because the papers were not changed frequently enough in the early stages of drying.

Microwave ovens

         Small numbers of specimens can be dried using a microwave oven. The technique recommended in the literature is to place the specimens between unprinted absorbent paper, for example butcher's paper, not newspaper, which is unsuitable because the chemicals present in the ink may cause a fire. The specimens should be put in a special press which should be of a microwave-safe material (wood, acrylic or polycarbonate sheeting e.g. plexiglass or perspex, NO metal components). If such a press is not available, sheets of cardboard can be placed above and below the specimens and then weighted down. Drying time depends on the power of your oven. In most cases drying is accomplished by irradiating at maximum power for 1-2 minutes per specimen, although it is often a case of trial and error. It is best to process no more than 10-12 specimens of average thickness per batch. Specimens are usually dried after the moisture that characteristically appears on the glass door has disappeared. If the specimen is damp when taken out of the oven, allow it to stand before re-radiating as moisture continues to evaporate from the specimen for some time. Care must be taken not to irradiate the specimens for too long.It should be noted that microwave treatment damages seeds and the cellular structure of the plants which may reduce the long-term value of the specimens.

Alternative drying techniques

         Silica gel/other desiccants & freeze drying

       Alternative methods of drying plant specimens have been used for some time, but are mostly restricted to special purpose collections. The main alternatives are freeze-drying and drying in a desiccant powder such as desiccant silica gel. In general these techniques are used where it is essential to preserve the shape of a delicate plant of organ of the plant such as the flower. Freeze-drying has also been used to preserve the chemical composition of a plant as accurately as possible for later study.Disadvantages and special conservation problems of specimens dried in these manners are that they are particularly susceptible to damage. The dried parts are fragile, lack support and often catch on packing materials. They must, therefore, be packed especially carefully and stored in small boxes or tubes with some appropriate packing material that does not snag and break small projections. Acid-free tissue paper is often used. Drying in desiccant silica gel crystals or powder can also have the disadvantage that it is difficult to remove all traces of the silica gel after drying. 

Special preservation and processing techniques

Wet or spirit collections

Very fleshy or delicate structures, including small algae and orchid flowers, are best preserved in an air-tight glass or plastic jar with a liquid preservative rather than by drying. The type of preservative used should be clearly labelled in the jar. Such material is often referred to as a spirit collection or wet collection. Most material can be satisfactorily preserved in 70% ethyl alcohol (or 70% methylated spirit or denatured alcohol) with 30% water. Your pharmacist can make this up for you and it will keep indefinitely in a tightly stoppered bottle. Colours will fade quickly in spirit, however, so it is a good idea to keep comprehensive notes and photographs.

Small algae

Microscopic algae are often collected in a jar and in the water in which they were found. If the algae are to be stored for more than 2-3 days, a preservative needs to be used. Traditionally this has been the extremely toxic formalin - a small amount can be added to the water to make a 5% final solution, and the container labelled. This must not be sent through the post or by courier. Thee are some other equally toxic options, for example propylene phenoxytol, but none should be sent through the post. A safer option is to add sufficient concentrated alcohol or methylated spirits  to the water containing the algae to make a final solution of 70% alcohol. This treatment dilutes the algae making them difficult to find, so if they can be concentrated somehow first (e.g. by filtering) they can be stored in much less liquid. Another option is to fix the algae in formalin (or something similar) first, and then prepare a microscope glass slide with a permanent water-soluble mounting medium.See also Collecting & examining freshwater algaeSome plants and certain climatic conditions require the use of specialised processing treatments. This is a brief summary:

Succulent plants  

             Very succulent plants e.g. cacti, many species of Ficus ('figs') and mistletoes drop their leaves entirely upon drying or remain alive for an excessively long period in the press. This is overcome by killing the plant before pressing, either by freezing the specimen for a few hours, dipping it in boiling water for a few minutes, or by using a microwave oven. The correct time in a microwave oven depends on the type of oven and the specimen itself, but is usually about 2 minutees. Succulent material is 'done' when it has a flaccid, water-soaked appearance.When the cell tissue has been killed (by freezing, scalding or radiation) the specimen will still require special attention until it has dried completely. The papers must be changed at least daily for the first few days, and complete drying in the case of cacti may take more than a month.An alternative technique is to place collected succulent material in 70% alcohol, as this preserves its original shape

.Bulky specimens

         Very bulky objects (e.g. Banksia spikes, thistle heads) may be cut or sawn lengthwise before pressing.

Orchids

          Orchids require particular care when pressing due to their delicate flowers.The flowers (at least one) should be spread out evenly so that the flower parts face the paper surface without creases or folds (never allow the parts to fold up or stick together).Alternatively, cut off each organ of a flower (three sepals, two lateral petals, a lip petal and the column attached to ovary) and spread these parts on the same piece of paper and then press. A superior method is to preserve the specimen as a spirit collection.

Water plants

        These should be carefully laid on a sheet of paper, excess water removed, then pressed and dried in the normal way. Very soft water plants may require special treatment such as being floated onto a sheet of paper immersed in water and then dried (as is usual for marine algae) or preerving in alcohol or formalin solutions).See also Collecting & examining freshwater algae 

Large algae

         These can be kept damp for a day or so, but it is preferable to dry specimens immediately. If very soft or filamentous, such plants may be best arranged on the mounting sheet while in a dish of shallow water. The mounting sheet is placed first into the dish and specimens on the sheet then gently slid from the water. Because such specimens tend to adhere to the drying papers they are best pressed between a mounting sheet (to which the underside of the specimen may remain permanently attached) and a sheet of adhesion-resistant material (e.g. muslin) to prevent the top of the specimen adhering to the drying papers.

Tropical conditions

          Under humid, tropical and coastal conditions special methods must be adopted to prevent rapid mould growth before the specimens can be placed in drying cabinets. Placing the entire bundle of drying papers and specimens in a plastic bag and adding a small quantity of ethyl alcohol (enough to saturate with vapour) is a method commonly adopted. This sometimes called the Schweinfurth method, after an Austrian botanist who collected extensively in tropical areas. Such methods alter specimen colours and should be avoided unless conditions make them essential. 

Mounting

         Mounting specimens prevents most fragile material from fragmenting and prevents specimens becoming separated from their labels. If the plant collection is a long-term project, specimens should be mounted on sheets of archival (permanent) cardboard or paper with archival-quality fixing media. These include stitching with cotton thread, dental floss, nickel-plated copper wire (for heavier specimens), narrow strips of archival paper, linen tape, or by using an archival adhesive such as methyl cellulose adhesive. A range of archival material is available from S& M Supply Company Pty Ltd.Dental floss can be used for bulky specimens by puncturing the sheet on either side of the specimen, threading the floss through and tying ends together in a simple reef knot. Another alternative is a clear, long-lasting 3M tape (Y8440) which is available as a special order from 3M ('Scotch brand') and their distributors. This tape has been in use in some Australian herbaria for approximately 15 years with good success. The use of tape is faster than most adhesives, and is easier to remove (by cutting and peeling from the specimen) if the specimen needs to be examined more thoroughly. Ordinary sticky tapes are unsuitable as the adhesive breaks down, becoming tacky and detached after a few years.One disadvantage of mounting specimens is that it can make parts of the specimen inaccessible for examination, so it is essential that this be borne in mind during specimen arrangement and mounting. For example, easily reversible mounting media should be used, specimens should be strapped to the sheet, rather than glued all over, and the specimen should be carefully arranged before it is attached so that it shows all features.Full-size herbarium mounting sheets are usually about 43 cm long x 28 cm wide. The plant name and accompanying field notes should be transcribed on a permanent label stuck to one corner of the herbarium sheet (the bottom right-hand corner being the most common) or, sometimes, annotations may be written directly on the sheet or card. Example specimen sheets from the NSW National Herbarium are illustrated in the diagrams. Cards 20 cm x 13 cm are a suitable size for personal reference sets of identified specimens but are unsuitable for research collections, Note: mounted specimens should not be placed in microwave ovens - adhesives often melt, and tape may ignite.Small pieces of material which may have become separated from the specimen (e.g. seeds) can be placed in small plastic bags and pinned to the sheet. 

Long-term preservation and storage

       The long-term preservation of dry plant specimens is largely dependent on protection from insect attack. Specimens collected by Linnaeus in the eighteenth century, and by Banks and Solander on the Endeavour voyage in 1788, are still excellently preserved.

Pests and their control

        A range of pests attack dried plant material. The most common pests are insects and fungi, though rodents and other large animals can cause damage in poor storage conditions. Insects eat the material, the paper surrounding the material, and the adhesives and mounting media. Such insect pests range from psocids (book lice), which attack mainly the softer parts such as flowers and soft fruits, to tobacco beetles and carpet beetles, which can bore holes through the toughest of specimens. Many insects are particularly sensitive to relative humidity levels and do not thrive at levels below 50%.

The most common and acceptable specimen treatments for insect control are:

       Freezing

      Freezing the specimens is the technique least dangerous to human health, and is very simple. The specimens must be frozen to -18^oC or colder and kept at that temperature for at least 48 hours. In practice, when specimens are frozen in domestic deep-freezers in bulk and/or in boxes, it is necessary to freeze them for 72 hours (3 days and 3 nights) to ensure that the centres of thick specimens and specimens in the middle of large bundles are reduced to a low enough temperature for long enough time to kill all pests. Bundles of specimens should be sealed in plastic bags to avoid moisture condensing on the sheets as they thaw, or alternatively, dry air should be circulated around the parcel in a desiccating cabinet during re-warming

Microwave

          Specimens may also be treated in a microwave oven to kill any animal life present on them. Microwave treatment is a fast method for small numbers of specimens. The technique is similar to microwave drying of specimens except that a press is not essential for already dry material, and times may be reduced from those required for drying. No absolute guidelines can be given as it is best to use trial and error testing for each set of circumstances and different types of microwave, but times of 1-2 minutes per dried plant specimen should be adequate.

Poisoning

          A traditional method of insect control was to poison the specimens with a chemical to make them unpalatable or deadly to pests. However, this is not recommended due to obvious health hazards. Domestic spray-type insecticide is of limited effectiveness and, to avoid staining, should not be sprayed directly on mounted sheets. Sprays may kill surface insects but, for instance, would not penetrate to insects living near the centre of a Banksia infructescence or 'cone'. Many spray insecticides are now regarded as possibly detrimental to human health, so health and safety should be carefully considered before these are used. It is essential that specimens that have been poisoned be so identified, both to warn users of the health risks involved and to avoid misleading any later chemical research using the specimens.

Insect deterrents

        A number of chemicals have been used or proposed for use as insect deterrents. Of these naphthalene (commonly found as 'moth balls') is probably the most commonly used in herbaria because of its reputation for reasonable effectiveness in insect control, coupled with low toxicity to humans. It should be noted, however, that naphthalene is poisonous if ingested, naphthalene dust can cause eye health problems for people with contact lenses, and chronic exposure is believed to be implicated in the formation of cataracts. Thee are also reports of naphtha vapour causing allergies and headaches and of possible carcinogenic effects at very high concentrations. Naphthalene in commercial quantities is most commonly available in flake or chip form. If left loose in containers/boxes it is more readily inhaled or ingested and is more likely to case problems to people with contact lenses than is naphthalene in block or ball form or naphtha flakes or chips encased in porous bags or boxes. If naphthalene is used as an insect deterrent the levels around specimens must be maintained at a steady, level to ensure effective insect control. Because of the exposure limits for humans this is best done by storing specimens in boxes or in a sealed cupboard.

Fungal pests

       Fungal (mould) attack is mainly a danger to damp specimens, either through incomplete drying during specimen preparation, or to collections that become wet later through flood, other water damage or improper storage conditions. Properly dried plant specimens will not suffer from fungal attack if stored in the correct conditions (see recommendations below) though freeze-dried fungal bodies such as mushrooms have been reported to be very susceptible to mould growth. Specimens with sugary exudations or large quantities of nectar are also particularly attractive to fungi, and need special care during drying to ensure that they dry fast enough to prevent mould growth.If fungus grows on the specimens these can be brushed with alcohol or methylated spirits (denatured alcohol). However, this may alter the specimen unacceptably for chemical and other investigative research, and only kills the fungus present on the specimen; it does not correct the problems that allowed the fungus to develop. Specimens treated for fungal attack should be clearly annotated as such, including date and treatment given.

Storage

      Dried and pressed plant specimens can be stored in cardboard or plastic boxes, or tied in bundles in light-weight cardboard folders placed in 'pigeon holes'. Alternatively, they can be placed in protective plastic jackets and displayed in ring folders which is recommended if they are to be frequently handled, such as for a reference collection.

Filing

      Specimens should be filed in a systematic order if a relatively permanent collection is being made. The major groups, i.e. ferns and fern allies, cycads, conifers, dicotyledons and monocotyledons, are best kept separately or according to some classification scheme, such as that given in a flora or handbook. Similarly, the genera within each family and the species within each genus may be filed alphabetically or following some such classification. 

TEACHING BY MODEL
Mood:  happy

Using models in science teaching and learning

“…the fundamental fact about learning: anything is easy if you can assimilate it into your collection of models…what an individual can learn, and how he learns it, depends on what models he has available. (Papert)

Introduction

Within the scientific community models are an important mechanism for advancing scientific understanding. This involves the construction, validation and application of scientific models. Science instruction should be designed to engage students in making and using models where possible If scientists use models as ‘thinking tools’, shouldn’t students also use them? Teachers can use models to help students make sense of their observations, and understand abstract ideas through the visualisation of

• objects that are too big, too small or positioned so it is difficult for them to be seen easily e.g. an ecosystem, cell, heart
• processes that cannot easily be seen directly e.g. digestion
• abstract ideas e.g. particulate nature of matter, energy transfer.

When using a model of any type with groups of students it should be made clear to them that it is a model they are using. A teacher cannot guarantee that the way he sees a model, or wants the students to see it, is actually the same way that the students do. It is important to introduce the idea that models can change over time and that models need only be ‘good enough’ to explain a particular concept or idea to meet the needs at that time.Science students who become actively involved in using models in their learning have been shown to gain a deeper understanding of the concepts and processes about which they are learning

Types of scientific models

Type	Description and example
Scale models	Version of the original that is easy to see e.g. anatomical models
Analogue models	Simplification of the original used to explain certain phenomena e.g. different types of atomic and molecular models
Mathematical models	Express a situation in terms of formulae e.g. gas laws
Theoretical models	Put forward an explanation of a situation based on previous scientific knowledge, experiences and observations e.g. the ‘big bang’ theory

 
Models in science teachingThese can mainly be classified into two groups – scientific models and teaching models:1.     Scientific models (or consensus models) represent the widely accepted scientific view of a concept or idea. It provides a representation or an explanation for a complex process.2.     Teaching models are used to help a learner understand or visualise an idea, process or system; they are visual or physical representations which helps explain the abstract idea or invisible structure to the learner. Analogies as teaching models, usually illustrative rather than explanatory, are explanations or stories based on an object very familiar to students.It is very important that students know when a model being used, and what type of model is being used e.g. in one lesson a scale model of the ear may be used, in another a ‘slinky’ is used as an analogical model to represent the movement of sound. The teacher needs to point out to the students the differences betweens these two uses of models. Effective use of modelling

• makes explicit the purpose and use of the model as a process of thinking
• takes into account pupils’ prior knowledge and experiences – creates links between an idea they have seen before and the one they are about to see
•  is matched to pupils’ ability and maturity
• maintains the pace of the lesson by using modelling for short periods only
• repeats the modelling of a process whenever necessary - some skills are best acquired through repeated practice.

If used inappropriately models can lead to development of misconception that can be hard to replace - learners should be taught the scope and limitation of the models.

Science thinking skills associated with making and using models

• recognising the similarity between models and the things they represent, e.g. recognising what is and isn’t a model of the heart
• assessing the strengths and limitations of models in explaining and predicting the behaviour of the objects or phenomena they represent
• creating models to explain things that cannot be observed directly e.g. acquiring images and understandings that come from drawing, painting, sculpting, music, role play
• using models to raise questions, communicate ideas, and test hypotheses in many different contexts e.g. carrying out an experiment with a model that is not possible or practical to do with the real thing

Examples of teaching models used in school science

• Electricity: teacher and students all become part of the ‘Big Circuit’.
• Conduction, convection and radiation: Students model the processes of heat energy transfer by passing a ‘parcel of energy’ along a line of linked pupils for conduction, by circulating to pick up a ‘parcel of energy’ and delivering it elsewhere before circulating to pick up some more, etc. The teacher models radiation by throwing ‘parcels of energy’ across the space.
• Reactivity series: Cards with the names of the metals are handed out to the students and they have to arrange themselves in a line in the correct order of reactivity.
• Resistance in an electrical circuit: the ‘rope through the hands’ used in a circle of students.
• Charged particles moving in an electrical circuit: golf balls in clear tube.
• Feeding relationships in a food web: students acting as producers/consumers arrange themselves to represent the food web.
• Human lungs: balloons in ball jar / bottle.
• Absorption through small intestine: Visking tubing.
• Transfer of sound energy: ‘slinky’.
• Atoms, molecules and bonding: various commercial or self-made model systems.
• Joints/muscles, heart, eye, etc: anatomical or self-made models.

Examples of analogies used in school science

·       Money as an analogy for energy.·       Camera as an analogy for the eye.·       Squeezing toothpaste as an analogy for peristalsis.·       Scissors as an analogy for digestive enzymes.

RAKAN-RAKAN LAMA SMK MELOR SPM 1978
Mood:  chatty

Assalamualaikum ,

Saya Shaari Omar ingin menjemput rakan-rakan lama SPM 1978 SMK Melor untuk bersama-sama dalam blok ini. Tujuannya untuk bertanya khabar kalian semua. Apa khabar Muhammad Jaafar, Nasron Omar, Azkah Ali, Muhammad Dollah, Zainal Abidin, Din Dollah, Mahani Yusoff, Zailani Awang, Zakiah, Mohd Shukri Hood dan yang lain-lain dah tak ingat nama. Semua classmate 5 sains Satu 1978 minta hubungi.

 

Wassalam.

BLOG ASHAARIO
Mood:  happy
selamat berjumpa dan selamat hari raya

SET INDUCTION
Mood:  blue
Now Playing: PART OF LESSON PLAN
Topic: LESSON PLAN

Set Induction

(SHA’ARI OMAR – IPKB)

 

What

Set induction is about preparation, usually for a formal lesson. When the students are set, they are ready to learn ('are you set?'). Set induction is thus about getting them ready, inducing them into the right mind-set.

How

Sets are used before any new activity, from introduction of a new concept to giving homework. It is important in each set both to create clarity about what is expected happen (both what you will do and what they should do), and to create motivation for this to occur, with students being fully engaged in the learning.

Set induction can be done by such as:

·        Explaining potential benefits to the learner.

·        Giving clear instructions.

·        Describing what is going to happen.

The STEP acronym may be used to help remember what to do:

·        Start: Welcome the students, settle them down and gain attention.

·        Transact: Understand their expectations and explain yours. Link with previous learning.

·        Evaluate: Assess the gap between their expectations and current reality. Clarify any discrepancies for them.

·        Progress: Move on to the main body of learning.

Why

Perrott (1982) identified four purposes of set induction.

1.   Focusing attention on what is to be learned by gaining the interest of students.

2.   Moving from old to new materials and linking of the two.

3.   Providing a structure for the lesson and setting expectations of what will happen.

4.   Giving meaning to a new concept or principle, such as giving examples.

So what?

So if you are teaching, think about and prepare carefully for getting your students in the right state of mind to be ready to understand and learn.

 

IN SITU CONSERVATION

How do we Conserve Biodiversity? There are two main ways to conserve biodiversity. These are termed ex situ (i.e. out of the natural habitat) and in situ (within the natural habitat)

Ex Situ Conservation - out of the natural habitat

(Species-based) Zoos - These may involve captive breeding programmes, Aquaria - research, public information and education Plant Collections - breeding programmes and seed storage n the past, zoos were mainly display facilities for the purpose of public enjoyment and education. As large numbers of the species traditionally on display have become rarer in the wild, many zoos have taken on the additional role of building up numbers through captive breeding programmes. Although comparatively far more invertebrates than vertebrates face extinction, most captive breeding programmes in zoos focus on vertebrates. Threats to vertebrate extinction tend to be well publicised (e.g. Dormouse, Panda). People find it easier to relate to and have sympathy with animals which are more similar to ourselves, particularly if they are cute and cuddly (at least in appearance, if not in fact!). Not many visitors to zoos are likely to get excited over the prospect of the zoo 'saving' a tiny beetle, which they can barely see, let alone spiders or other invertebrates which often invite horror rather than wonder. Vertebrates therefore serve as a focus for public interest. This can help to generate financial support for conservation and extend public education to other issues. This is a very important consideration, as conservation costs money and needs to be funded from somewhere. The focus on vertebrates is not solely pragmatic. Many of the most threatened vertebrates are large top carnivores, which the world stands to lose in disproportionate numbers. Such species require extensive ranges to provide sufficient prey to sustain them. In many cases, whole habitats for these predators have all but disappeared. Some biased expenditure on their survival may therefore be justified. Several species are now solely represented by animals in captivity. Captive breeding programmes are in place for numerous species. At least 18 species have been reintroduced into the wild following such programs. In many cases the species was actually extinct in the wild at the time of reintroduction (Arabian Oryx, Pere David Deer, American Bison). In some cases, all remaining individuals of a species, whose numbers are too low for survival in the wild, have been captured and the species has then been reintroduced after captive breeding (California Condor). The role of zoos in conservation is limited both by space and by expense. At population sizes of roughly 100-150 individuals per species, it has been estimated that world zoos could sustain roughly 900 species. Populations of this size are just large enough to avoid inbreeding effects. However, zoos are now shifting their emphasis from long-term holding of species, to returning animals to the wild after only a few generations. This frees up space for the conservation of other species. Genetic management of captive populations via stud records is essential to ensure genetic diversity is preserved as far as possible. There are now a variety of international computerised stud record systems which catalogue genealogical data on individual animals in  zoos around the world. Mating can therefore be arranged by computer, to ensure that genetic diversity is preserved and in-breeding minimised (always assuming the animals involved are prepared to co-operate). Research has led to great advances in technologies for captive breeding. This includes techniques such as artificial insemination, embryo transfer and long-term cryogenic (frozen) storage of embryos. These techniques are all valuable because they allow new genetic lines to be introduced without having to transport the adults to new locations. Therefore the animals are not even required to co-operate any longer. However, further research is vital. The success of zoos in maintaining populations of endangered species is limited. Only 26 of 274 species of rare mammals in captivity are maintaining self-sustaining populations (World Resources Institute). Reintroduction of species to the wild poses several different problems. Diseases The introduction of new diseases to the habitat, which can decimate existing wild populations. Alternatively, the loss of resistance to local diseases in captive-bred populations. Behaviour Behaviour of captive-bred species is also a  problem. Some behaviour is genetically determined and innate, but much has to be learned from other adults of the species, or by experience. Captive-bred populations lack the in situ learning of their wild relatives and are therefore at a huge disadvantage in the wild. In one case of reintroduction, a number of monkeys starved because they had no concept of having to search for food to eat - it had always been supplied to them in captivity. In the next attempt, the captive monkeys were taught that they had to look for food, by hiding it in their cages, rather than just supplying it.  Genetic Races Reintroduced populations may be of an entirely different genetic make-up to original populations. This may mean that there are significant differences in reproduction habits and timing, as well as differences in general ecology. Reintroduction of individuals of a species into an area where the species has previously become extinct, is in many cases just like introducing a foreigner. The Large Copper Butterfly is a good example of this. Although extinct in Britain, it persists in continental Europe. There have been over a dozen attempts to re-establish it in Britain over the last century, but none have been successful. This is probably due to the differing ecology of the introduced races. Replacement of extinct populations by reintroduction from other areas may not therefore be an option. Habitat The habitat must be there for reintroduction to take place. In many cases, so much habitat has been destroyed, that areas must first be restored to allow captive populations to be reintroduced. Suitable existing habitats will also (unless the species is extinct in the wild) usually already contain wild members of the species. In this case, it is likely that within the habitat, there are already as many individuals as the habitat can support. The introduction of new individuals will only lead to stress and tension as individuals fight for limited territory and resources such as food. In this case, nothing positive has been accomplished by reintroduction, it has merely increased the stress on the species. It may even in some cases result in a decrease in numbers. In contrast, the provision of additional restored habitat nearby can allow wild populations to expand into it without the need for reintroduction.   AQUARIA The role of aquaria has largely been as display and educational facilities. However, they are assuming new importance in captive breeding programmes. Growing threats to freshwater species in particular, are leading to the development of ex situ breeding programmes. The World Conservation Union (IUCN) is currently developing captive breeding programmes for endangered fish. Initially this will cover those from Lake Victoria in Africa, the desert fishes of N. America and Appalachian stream fishes. Natural habitats will be restored as part of the programme. Marine, as well as freshwater species are also the subject of captive breeding programmes. For example, The National Marine Aquarium, in South West England, is playing an important role in the conservation of sea horse species through their captive breeding programme. ZZOOS n the past, zoos were mainly display facilities for the purpose of public enjoyment and education. As large numbers of the species traditionally on display have become rarer in the wild, many zoos have taken on the additional role of building up numbers through captive breeding programmes. Although comparatively far more invertebrates than vertebrates face extinction, most captive breeding programmes in zoos focus on vertebrates. Threats to vertebrate extinction tend to be well publicised (e.g. Dormouse, Panda). People find it easier to relate to and have sympathy with animals which are more similar to ourselves, particularly if they are cute and cuddly (at least in appearance, if not in fact!). Not many visitors to zoos are likely to get excited over the prospect of the zoo 'saving' a tiny beetle, which they can barely see, let alone spiders or other invertebrates which often invite horror rather than wonder. Vertebrates therefore serve as a focus for public interest. This can help to generate financial support for conservation and extend public education to other issues. This is a very important consideration, as conservation costs money and needs to be funded from somewhere. The focus on vertebrates is not solely pragmatic. Many of the most threatened vertebrates are large top carnivores, which the world stands to lose in disproportionate numbers. Such species require extensive ranges to provide sufficient prey to sustain them. In many cases, whole habitats for these predators have all but disappeared. Some biased expenditure on their survival may therefore be justified. Several species are now solely represented by animals in captivity. Captive breeding programmes are in place for numerous species. At least 18 species have been reintroduced into the wild following such programs. In many cases the species was actually extinct in the wild at the time of reintroduction (Arabian Oryx, Pere David Deer, American Bison). In some cases, all remaining individuals of a species, whose numbers are too low for survival in the wild, have been captured and the species has then been reintroduced after captive breeding (California Condor). The role of zoos in conservation is limited both by space and by expense. At population sizes of roughly 100-150 individuals per species, it has been estimated that world zoos could sustain roughly 900 species. Populations of this size are just large enough to avoid inbreeding effects. However, zoos are now shifting their emphasis from long-term holding of species, to returning animals to the wild after only a few generations. This frees up space for the conservation of other species. Genetic management of captive populations via stud records is essential to ensure genetic diversity is preserved as far as possible. There are now a variety of international computerised stud record systems which catalogue genealogical data on individual animals in  zoos around the world. Mating can therefore be arranged by computer, to ensure that genetic diversity is preserved and in-breeding minimised (always assuming the animals involved are prepared to co-operate). Research has led to great advances in technologies for captive breeding. This includes techniques such as artificial insemination, embryo transfer and long-term cryogenic (frozen) storage of embryos. These techniques are all valuable because they allow new genetic lines to be introduced without having to transport the adults to new locations. Therefore the animals are not even required to co-operate any longer. However, further research is vital. The success of zoos in maintaining populations of endangered species is limited. Only 26 of 274 species of rare mammals in captivity are maintaining self-sustaining populations (World Resources Institute). Reintroduction of species to the wild poses several different problems. Diseases The introduction of new diseases to the habitat, which can decimate existing wild populations. Alternatively, the loss of resistance to local diseases in captive-bred populations. Behaviour Behaviour of captive-bred species is also a  problem. Some behaviour is genetically determined and innate, but much has to be learned from other adults of the species, or by experience. Captive-bred populations lack the in situ learning of their wild relatives and are therefore at a huge disadvantage in the wild. In one case of reintroduction, a number of monkeys starved because they had no concept of having to search for food to eat - it had always been supplied to them in captivity. In the next attempt, the captive monkeys were taught that they had to look for food, by hiding it in their cages, rather than just supplying it.  Genetic Races Reintroduced populations may be of an entirely different genetic make-up to original populations. This may mean that there are significant differences in reproduction habits and timing, as well as differences in general ecology. Reintroduction of individuals of a species into an area where the species has previously become extinct, is in many cases just like introducing a foreigner. The Large Copper Butterfly is a good example of this. Although extinct in Britain, it persists in continental Europe. There have been over a dozen attempts to re-establish it in Britain over the last century, but none have been successful. This is probably due to the differing ecology of the introduced races. Replacement of extinct populations by reintroduction from other areas may not therefore be an option. Habitat The habitat must be there for reintroduction to take place. In many cases, so much habitat has been destroyed, that areas must first be restored to allow captive populations to be reintroduced. Suitable existing habitats will also (unless the species is extinct in the wild) usually already contain wild members of the species. In this case, it is likely that within the habitat, there are already as many individuals as the habitat can support. The introduction of new individuals will only lead to stress and tension as individuals fight for limited territory and resources such as food. In this case, nothing positive has been accomplished by reintroduction, it has merely increased the stress on the species. It may even in some cases result in a decrease in numbers. In contrast, the provision of additional restored habitat nearby can allow wild populations to expand into it without the need for reintroduction.   AQUARIA The role of aquaria has largely been as display and educational facilities. However, they are assuming new importance in captive breeding programmes. Growing threats to freshwater species in particular, are leading to the development of ex situ breeding programmes. The World Conservation Union (IUCN) is currently developing captive breeding programmes for endangered fish. Initially this will cover those from Lake Victoria in Africa, the desert fishes of N. America and Appalachian stream fishes. Natural habitats will be restored as part of the programme. Marine, as well as freshwater species are also the subject of captive breeding programmes. For example, The National Marine Aquarium, in South West England, is playing an important role in the conservation of sea horse species through their captive breeding programme Populations of plant species are much easier than animals to maintain artificially. They need less care and their requirements for particular habitat conditions can be provided more readily. It is also much easier to breed and propagate plant species in captivity. There are roughly 1,500 botanic gardens world-wide, holding 35,000 plant species (more than 15% of the world’s flora). The Royal Botanic Gardens of England (Kew Gardens) contains an estimated 25,000 species. IUCN classifies 2,700 of these as rare, threatened or endangered. Many botanic gardens house collections of particular taxa which are of major conservation value. There is however, a general geographic imbalance. Only 230 of the world’s 1,500 gardens are in the tropics. Considering the greater species richness of the tropics, this is an imbalance that needs to be addressed. A more serious problem with ex situ collections involves gaps in coverage of important species, particularly those of significant value in tropical countries. One of the most serious gaps is in the area of crops of regional importance, which are not widely traded on world markets. These often have recalcitrant seeds (unsuited to long-term storage) and are poorly represented in botanic collections. Wild crop relatives are also under-represented. These are a potential source of genes conferring resistance to diseases, pests and parasites and as such are a vital gene bank for commercial crops. Plant genetic diversity can also be preserved ex situ through the use of seed banks. Seeds are small but tough and have evolved to survive all manner of adverse conditions and a host of attackers. Seeds can be divided into two main types, orthodox and recalcitrant. Orthodox seeds can be dried and stored at temperatures of -20oC. Almost all species in a temperate flora can be stored in this way. Surprisingly, many tropical seeds are also orthodox. Recalcitrant seeds, in contrast, die when dried and frozen in this manner. Acorns of oaks are recalcitrant and it is believed that so are the seeds of most tropical rain forest trees. The result of storing seeds under frozen conditions is to slow down the rate at which they lose their ability to germinate. Seeds of crop plants such as maize and barley could probably survive thousands of years in such conditions, but for most plants, centuries is probably the norm. This makes seed banking an attractive conservation option, particularly when all others have failed. It offers an insurance technique for other methods of conservation. All of the ex situ conservation methods discussed have their role to play in modern conservation. Generally, they are more expensive to maintain and should be regarded as complementary to in situ conservation methods. For example they may be the only option where in situ conservation is no longer possible.

ZOOS

BIODIVERSITY

Biodiversity and Conservation

What is Biodiversity?

Biodiversity is a modern term which simply means " the variety of life on earth". This variety can be measured on several different levels.

Genetic - variation between individuals of the same species. This includes genetic variation between individuals in a single population , as well as variations between different populations of the same species. Genetic differences can now be measured using increasingly sophisticated techniques. These differences are the raw material of evolution.

Species - species diversity is the variety of species in a given region or area. This can either be determined by counting the number of different species present, or by determining taxonomic diversity. Taxonomic diversity is more precise and considers the relationship of species to each other. It can be measured by counting the number of different taxa (the main categories of classification) present. For example, a pond containing three species of snails and two fish, is more diverse than a pond containing five species of snails, even though they both contain the same number of species. High species biodiversity is not always necessarily a good thing. For example, a habitat may have high species biodiversity because many common and widespread species are invading it at the expense of species restricted to that habitat.

Ecosystem - Communities of plants and animals, together with the physical characteristics of their environment (e.g. geology, soil and climate) interlink together as an ecological system, or 'ecosystem'. Ecosystem diversity is more difficult to measure because there are rarely clear boundaries between different ecosystems and they grade into one another. However, if consistent criteria are chosen to define the limits of an ecosystem, then their number and distribution can also be measured.

How many species are there?

Estimates of global species diversity vary enormously because it is so difficult to guess how many species there may be in less well explored habitats such as untouched rain forest. Rain forest areas which have been sampled have shown such amazing biodiversity (nineteen trees sampled in Panama were found to contain 1,200 different beetle species alone!) that the mind boggles over how many species there might remain to be discovered in unexplored rain forest areas and microhabitats.

Global species estimates range from 2 million to 100 million species. Ten million is probably nearer the mark. Only 1.4 million species have been named. Of these, approximately 250,000 are plants and 750,000 are insects. New species are continually being discovered every year. The number of species present in little-known ecosystems such as the soil beneath our feet and the deep sea can only be guessed at. It has been estimated that the deep sea floor may contain as many as a million undescribed new species. To put it simply, we really have absolutely no idea how many species there are!

 Losses of Biodiversity

Extinction is a fact of life. Species have been evolving and dying out ever since the origin of life. One only has to look at the fossil record to appreciate this. (It has been estimated that surviving species constitute about 1% of the species that have ever lived.) However, species are now becoming extinct at an alarming rate, almost entirely as a direct result of human activities. Previous mass extinctions evident in the geological record are thought to have been brought about mainly by massive climatic or environmental shifts. Mass extinctions as a direct consequence of the activities of a single species are unprecedented in geological history.

The loss of species in tropical ecosystems such as the rain forests, is extremely well-publicised and of great concern. However, equally worrying is the loss of habitat and species closer to home in Britain. This is arguably on a comparable scale, given the much smaller area involved.

Predictions and estimates of future species losses abound. One such estimate calculates that a quarter of all species on earth are likely to be extinct, or on the way to extinction within 30 years. Another predicts that within 100 years, three quarters of all species will either be extinct, or in populations so small that they can be described as "the living dead".

It must be emphasised that these are only predictions. Most predictions are based on computer models and as such, need to be taken with a very generous pinch of salt. For a start, we really have no idea how many species there are on which to base our initial premise. There are also so many variables involved that it is almost impossible to predict what will happen with any degree of accuracy. Some species actually benefit from human activities, while many others are adversely affected. Nevertheless, it is indisputable that if the human population continues to soar, then the ever increasing competition with wildlife for space and resources will ensure that habitats and their constituent species will lose out.

It is difficult to appreciate the scale of human population increases over the last two centuries. Despite the horrendous combined mortality rates of two World Wars, Hitler, Stalin, major flu pandemics and Aids, there has been no dampening effect on rising population levels. In 1950, the world population was 2.4 billion. Just over 50 years later, the world population has almost tripled, reaching 6.5 billion.

In the UK alone, the population increases by the equivalent of a new city every year. Corresponding demands for a higher standard of living for all, further exacerbates the problem. It has been estimated that if everyone in the world lived at the UK standard of living (and why should people elsewhere be denied this right) then we would either need another three worlds to supply the necessary resources or alternatively, would need to reduce the world population to 2 billion.

The only possible conclusion is that unless human populations are substantially reduced, it is inevitable that biodiversity will suffer further major losses.

 

BIODIVERSITY

Biodiversity and Conservation

What is Biodiversity?

Biodiversity is a modern term which simply means " the variety of life on earth". This variety can be measured on several different levels.

Genetic - variation between individuals of the same species. This includes genetic variation between individuals in a single population , as well as variations between different populations of the same species. Genetic differences can now be measured using increasingly sophisticated techniques. These differences are the raw material of evolution.

Species - species diversity is the variety of species in a given region or area. This can either be determined by counting the number of different species present, or by determining taxonomic diversity. Taxonomic diversity is more precise and considers the relationship of species to each other. It can be measured by counting the number of different taxa (the main categories of classification) present. For example, a pond containing three species of snails and two fish, is more diverse than a pond containing five species of snails, even though they both contain the same number of species. High species biodiversity is not always necessarily a good thing. For example, a habitat may have high species biodiversity because many common and widespread species are invading it at the expense of species restricted to that habitat.

Ecosystem - Communities of plants and animals, together with the physical characteristics of their environment (e.g. geology, soil and climate) interlink together as an ecological system, or 'ecosystem'. Ecosystem diversity is more difficult to measure because there are rarely clear boundaries between different ecosystems and they grade into one another. However, if consistent criteria are chosen to define the limits of an ecosystem, then their number and distribution can also be measured.

How many species are there?

Estimates of global species diversity vary enormously because it is so difficult to guess how many species there may be in less well explored habitats such as untouched rain forest. Rain forest areas which have been sampled have shown such amazing biodiversity (nineteen trees sampled in Panama were found to contain 1,200 different beetle species alone!) that the mind boggles over how many species there might remain to be discovered in unexplored rain forest areas and microhabitats.

Global species estimates range from 2 million to 100 million species. Ten million is probably nearer the mark. Only 1.4 million species have been named. Of these, approximately 250,000 are plants and 750,000 are insects. New species are continually being discovered every year. The number of species present in little-known ecosystems such as the soil beneath our feet and the deep sea can only be guessed at. It has been estimated that the deep sea floor may contain as many as a million undescribed new species. To put it simply, we really have absolutely no idea how many species there are!

 Losses of Biodiversity

Extinction is a fact of life. Species have been evolving and dying out ever since the origin of life. One only has to look at the fossil record to appreciate this. (It has been estimated that surviving species constitute about 1% of the species that have ever lived.) However, species are now becoming extinct at an alarming rate, almost entirely as a direct result of human activities. Previous mass extinctions evident in the geological record are thought to have been brought about mainly by massive climatic or environmental shifts. Mass extinctions as a direct consequence of the activities of a single species are unprecedented in geological history.

The loss of species in tropical ecosystems such as the rain forests, is extremely well-publicised and of great concern. However, equally worrying is the loss of habitat and species closer to home in Britain. This is arguably on a comparable scale, given the much smaller area involved.

Predictions and estimates of future species losses abound. One such estimate calculates that a quarter of all species on earth are likely to be extinct, or on the way to extinction within 30 years. Another predicts that within 100 years, three quarters of all species will either be extinct, or in populations so small that they can be described as "the living dead".

It must be emphasised that these are only predictions. Most predictions are based on computer models and as such, need to be taken with a very generous pinch of salt. For a start, we really have no idea how many species there are on which to base our initial premise. There are also so many variables involved that it is almost impossible to predict what will happen with any degree of accuracy. Some species actually benefit from human activities, while many others are adversely affected. Nevertheless, it is indisputable that if the human population continues to soar, then the ever increasing competition with wildlife for space and resources will ensure that habitats and their constituent species will lose out.

It is difficult to appreciate the scale of human population increases over the last two centuries. Despite the horrendous combined mortality rates of two World Wars, Hitler, Stalin, major flu pandemics and Aids, there has been no dampening effect on rising population levels. In 1950, the world population was 2.4 billion. Just over 50 years later, the world population has almost tripled, reaching 6.5 billion.

In the UK alone, the population increases by the equivalent of a new city every year. Corresponding demands for a higher standard of living for all, further exacerbates the problem. It has been estimated that if everyone in the world lived at the UK standard of living (and why should people elsewhere be denied this right) then we would either need another three worlds to supply the necessary resources or alternatively, would need to reduce the world population to 2 billion.

The only possible conclusion is that unless human populations are substantially reduced, it is inevitable that biodiversity will suffer further major losses.

 

BIODATA
Mood:  bright
Dilahirkan di Kelantan. Negeri yang paling masyhor akan kecerdikan rakyatnya dalam sepak terajang politik negara Malaysia. Berkelulusan Master of Environment, Bachelor in Agriculture Science, Diploma in Agric, Diploma in Education (PJK). Pelajar terbaik SRP  (1976) di SMK Melor dan pelajar terbaik SPM (1978). Pemidato terbaik Fakulti Pertanian UPM (1979). Mendapat Pangkat Leftenan Muda (ROTU) 1982. Pengalaman bekerja sebagai Sukarelawan Negara 1985-1986. Pegawai di Jabatan Pertanian dan Pengurus Besar Koperasi di RISDA (1986 -1992). Pegawai Perhubungan Awam MPKB 1993. Guru Biologi dan Sains Pertanian (1994-2007). Pensyarah di jabatan Sains IPKB mulai 2007.