Just as we need air and water tolive, we also need biodiversity

to survive. Between 8500-5500 B.C.people began to settle in places

where there was water and toraise animals and plants for food.

In the 12 000 years since then, plantsand animals have become adapted

and refined so they work better for us.As man started to eat the plants that

grew close by (usually weeds), he wouldchoose and grow those that he liked or

those that worked best – by savingseeds to grow the following year. In

this way, man selected specific plantsthat best suited the environment. By

doing this for hundreds of years, theplants have changed significantly. For

example, maize, (which is actually a grass)which we use and eat as pap, mealies,

popcorn, or as flour to make bread, originatedfrom a grass called teosinte, which can still

be found today in south western Mexico.

Using biodiversityEven today, we are continuing to explore the world tofind new living things that we can use.

Bioprospecting, which is also known as biodiversityprospecting, is the exploration of biological material

for commercially valuable genetic and biochemicalproperties. Small samples of natural resources arecollected for their potential value to industry, particularlyfor the pharmaceutical industry (“medicine makers”).

There are many diseases worldwide that need newdrug treatments, such as cancer, HIV/AIDS, TB, andmalaria. Local communities close to where the biodiversityis found may have specialised knowledge on how it isused, and this knowledge, which can also be collected,is known as traditional or indigenous knowledge (IK).For example, local healers often use (medicinal) plantsin their treatments, and know where to find the plantsand how to use them.

However, not just anyone can go and collect plantsand animals from the wild, especially if they are goingto use them to make lots of money. They need to obtain

permission first from the owners and agree to sharethe profits with them ahead of time. Whenbiodiversity or related knowledge is collected

without permission from the owners of theseresources and then patented (i.e. exclusive rightsto make money from their discovery or invention),it is known as biopiracy.

Types of diversityBiodiversity can be divided into three types of diversity:

Ecosystem or environment diversity: The diversity of environmentswhich are made up of the habitats that plants and animals callhome, e.g. forests, mountains, deserts, and oceans.

Species Diversity: Animals, plants and other living things that aresimilar and share common characteristics and can breed witheach other are classified as a species, e.g. the human species.The variety of species within an area is measured by how manydifferent species there are or by how closely related they are in aspecific habitat. There are thought to be about 100 millionspecies of living things in the world.South Africa is one of the world’smost biologically diversecountries with more than23 000 plant species(more than 8% of theworld’s total).

Genetic diversity:There are bigdifferences betweenmembers of the samespecies due to a variationin the genes, e.g. humansare all the same speciesbut are all “different”according to theirspecific genetic“recipe”. Just asthere are differencesbetween peoplethere are differenceswithin other species.

Biodiversity (bio=life and diversity=variety) refers toall living things found on Earth, including plants,

animals, insects, marine life and microbes. Wemake use of this biodiversity every day. It provides

us with the resources we need, including the food that weeat, the clothes we wear, the medicines we take, the houses

we live in, and for many other manufacturing processes.

Biodiversity– the variety of life

In comparison to teosinte, modern maizehas much larger, exposed seeds whichdo not fall off the plant when they ripen –enabling them to be harvested all at thesame time. Although modern maize andteosinte look very different (phenotype),their genetic recipes (genotypes) arealmost identical.

Similarly, animalssuch as cows havebeen selected to producemore meat, milk andleather – resulting inpopular cattle breedsraised today such asthe Aberdeen-Angusand Jersey breeds. Thisprocess of adaptingplants and animalsfor human use iscalled domestication.

Today, domestication ofplants and animals still happens, andalthough farmers are still involved, specialistplant and animal breeders have refined theprocess further. New technology has alsodeveloped new ways of changing thegenetic make-up of plants and animalsto make them better suited to their specificneeds and environmental conditions, suchas genetically modified foods.

Bananas✔ Bananas are thought to be the

first fruit eaten by humans, andoriginate in Southeast Asia.

✔ Bananas are not trees – they areactually one of the largest herbsin the world.

✔ Banana is the 4th most importantcrop in developing countries(after rice, wheat and maize).

✔ Bananas are cooked and eaten as a vegetable inmany parts of the world.

✔ Bananas are one of the richest sources of vitamin B6 (whichkeeps your brain working well), carbohydrates, phosphorus,calcium, potassium and vitamin C.

✔ Bananas keep ripening after they’re picked,which is why they turn from green to yellow.

✔ Bananas were named after the Arabword for finger, “bana” and a bunch ofbananas is called a “hand”.

✔ Other parts of the banana plant are alsoused, including the leaves to roof houses,as umbrellas, and as dinner plates. Banana fibres are usedin textiles, book binding, making hats and fishing nets.

EasyScienceis produced by the South

African Agency for Scienceand Technology

Advancement(SAASTA), an

operational unitof the National

Research Foundation.SAASTA’s mission isto promote the publicunderstanding,appreciation andengagement withscience andtechnology amongall South Africans.

Visit the website:www.saasta.ac.za for

more information.

HoodiaIn South Africa, the best known exampleof successful bioprospecting is a species of

Hoodia, a succulent plant indigenous tosouthern Africa.

Scientists at the Council for Scientific and IndustrialResearch (CSIR), based on the San’s traditional

knowledge, have extracted a substance from Hoodiawhich can be used for the management of obesity. Thisis the first natural food ingredient that can be used forweight management based on a plant originating fromAfrica. The scientists and the indigenous San peoplehave agreed to share the money made from thecommercialisation of the product – because the Sanpeople knew how to use the plant, and the scientistshave refined the active ingredient of the plant making iteasier to use and more effective. This type of work takesmany years – research on Hoodia started in 1963 and itis still being developed and should be available in a fewyears. It takes so long because it has to be thoroughlytested and approved before humans are allowed to take it.

Where did ourcrops originate?Crop plants that are eaten todayacross the world originate fromdifferent places, usually wherethey were first domesticatedthrough farming. They werespread by the wind and waves,caught in the fur of animals orcarried by people journeying toother countries, such as theearly explorers.

Onions: Central Asia

Maize: South America

Rice: Africa and India

Yams: West Africa

Potatoes: South America(Peru & Bolivia)

Banana:Southeast Asia

Tomatoes:South America

Carrots:Afghanistan

Beans: Mexico

Source: Bioversity International (www.bioversityinternational.org)

Biodiversity– the variety of life

Photograph from CSIR

Source: Bioversity International (www.bioversityinternational.org)

Source: www.nsf.gov

Loss of diversityAlthough biodiversity and the different types of

diversity provide us with the resources we need tolive, we are not using these resources sustainably.

Biodiversity is a renewable resource – meaning that it cangrow and replace itself if the habitat remains the same

and there are enough to reproduce. Despite this,human impact is continuing to decimate biodiversity,

causing whole ecosystems and species to be destroyed, and theprecious diversity within species to be reduced. Losing this

diversity means we are losing the ability to adapt tochanges, such as new diseases and pests orenvironmental conditions such as increasedtemperatures or droughts. Pollution, over-fishing,HIV/AIDS, climate change, building construction,

urbanisation, intensive agriculture and forestry,and war are some examples of how we are

destroying our environment. With almost one third of the world’s land area

being used for agriculture and the intense pressureto feed the growing world population from the

available agricultural land, intensive agricultureis the single largest cause of habitat loss. In addition, crops that have been specifically adapted to

certain habitats and production methods areused by farmers in large numbers, causing thebiodiversity to become very uniform and narrow.

Today, only about 15 plant species and eight animalspecies supply 90% of our food and about 60% of ourcalories come from just three foods (rice, wheat and maize).In the past 100 years, as much as 75% of the genetic diversityof agricultural crops may have been lost.

Careers related to biodiversityIt is likely that there will always be jobs related tobiodiversity, as we use it in every aspect of our dailylives. There are many different types of related jobs andyou can either choose a career that involves conservingbiodiversity, such as a plant collector or conservation

biologist, or you can choose a career that involvesstudying and using biodiversity, such as a plantbreeder or molecular plant biologist.

✔Plant collectors collect plants from different places both within South Africa and in other countries, soyou need to be adventurous and keen to explore

the outdoors.

✔ Conservation biologists study animals thatare in danger of becoming extinct to see why

this is happening and the impact it may have.

✔ Plant breeders and molecular biologists develop newtypes of plants, and usually specialise in one type

of plant – jobs that both require lots of patienceand the ability to work systematically with aneye for detail.

Biology, physical science and maths areimportant school subjects for all these types of

jobs. There are lots of related careersin this field, and jobs are available

in research institutes, universities,private companies, zoos and botanical gardens.

ConservationIronically, since the process we use to improveand adapt biodiversity for our use (i.e. intensiveagriculture) usually causes diversity to be lost, weneed to ensure that this diversity is preservedsomehow. This may be needed in the future tofight new diseases and environmental conditions.

To help conserve this diversity, genebanks have beenset up all over the world to store the seeds and plants

containing this diversity. Genebanks are an example ofex situ collections, meaning that they are “off site”, awayfrom the natural environments in which they grow – atype of insurance policy in case the diversity is lost innature. The genebanks also provide diversity for plantbreeders to use to make better crops.

For plants that produce seeds, such as rice, wheat andmaize, once collected, the seeds are cleaned, dried andplaced in a sealed jar or packet, and can be kept for up to100 years if they are kept at -18 to -20˚C. To ensure they arestill viable (can germinate), some of the seeds are grownout to replace the seeds with new ones every few years.Some plants, such as potatoes and yams, are grown fromtubers, or the storage organ of the plant, and so thesehave to be stored instead of the seeds. Other plants pro-duce “recalcitrant” seeds, which require more sophisticatedconservation techniques. Worldwide, there are thought tobe somewhere between 1 500 – 2 000 genebanks.

Activity:Start your own seed collection.Source: Bioversity International (www.bioversityinternational.org)

1) Go on a collecting mission: collect as many different kindsof seeds as you can. Collect seeds from the fruits andvegetables that you eat and from your neighbours.

2) Write down a description of the seeds you have collected.Where did you collect them from? What date? What dothey look like? Do they have a smell?

3) Clean the seeds and spread them on paper in a coolroom. After a few days they should be dry enough to store.

4) Place the seeds in airtight jars or plastic pill bottles. Puteach different type of seed in its own jar and screw on thelid tightly. Label the jar with the date, collection place andany other important information.

5) Put the containers on ashelf in a cool, dryplace. Check themevery few monthsand throw away anyof the seeds thatappear to be mouldy.

6) Test the seeds from time to time. Put them onsome wet blotting paper or newspaper in a dish with aloose fitting lid. Keep the dish in a warm place for a weekor so and keep checking on them. The seedsthat start to grow are still alive. Whenthey get bigger you can plantthem in a pot or in theground and watchthem grow.

Irish potato blightAlthough potatoes are the most important rootcrop in the world today, in 1845 a disease calledpotato blight caused all the potato crops inIreland to fail. The disease is a fungus (calledPhytophthera infestans) which makes the pota-toes go black, rotten and smelly and also wilts theleaves – making it impossible to eat. Sincepotatoes were the main source of food at thetime, thousands of people died. The Irish populationwas reduced by almost 25%, with a millionpeople dying from starvation and a million moreemigrating to America to find a better life.The problem was that the entire crop was basedon only a few varieties of potato which weresusceptible to the disease. This very narrowgenetic base, caused by people selecting andgrowing only a few types, meant that none ofthe varieties being grown had resistance to thedisease. This example shows how importantdiversity is and how it can impact our lives.It was only 40 yearslater that a curewas found forthe disease,which stillexiststoday. The PUB programme is an initiative of the Department of

Science and Technology and is implemented by SAASTA.The mandate of PUB is to promote a clear, balanced

understanding of the potential of biotechnology and toensure broad public awareness, dialogue and debate aboutbiotechnology and its current and potential applications.

Sock GardenSource: http://pbskids.org

What you need:❖ An old sock❖ A shoebox❖ Garbage bag or plastic wrap/cling film❖ Potting soil ❖ Scissors

What to do:1) The best time to do this is in

later summer/early autumn ona sunny day.

2) Find and put on an old, fuzzy, wornout sock that will fit over your shoe.

3) Go outside and walk around whereplants are growing. Keep a note ofwhere you went.

4) Take the sock off and examinethe kinds of seeds that havestuck to the sock.

5) Line the shoebox with the garbagebag or cling film.

6) Fill the shoebox with potting soil.

7) Cut a slit down the side of your sockand open it up. Flatten it and lay it ontop of the soil with the seeds facing up.

8) Cover it with a thin layer of soil andwater it.

9) In about a week, the seedsshould begin tosprout and youshould be able tosee what kind ofplants you have.

3333 4444 MMMMiiiinnnn iiiiMMMM aaaagggg MMMMiiiinnnn iiiiMMMMaaaagggg 3333 5555