The World of Plants
Variety
Use
Commercial exploitationNeed for maintaining variety
Living Things
Plant Kingdom
Do not produce seeds Produce seeds
Gymnosperms
Angiosperms
Algae Fungi Mosses Ferns
ConifersMonocotyledon Dicotyledon
Variety of plants
Advantages of having a wide variety of plants
Food
Medicine
Poppy
Foxglove
Mandrake
Rosy periwinkle
Medicinal plants
common common namename
poppypoppy foxglovefoxglove mandrakemandrake rosy rosy periwinklperiwinkl
ee
scientific scientific namename
drug drug extractedextracted
use of use of drugdrug
Papaver somniferum
Digitalislanata
Mandragoraofficinarum
Catharanthusroseus
morphine digitoxin hyosycamine vincristine
relief of pain
treatment of heart disease
sedation of patient before
operation
treatment of
leukaemia
plantplant Plant Plant organ organ eateneaten
ProteiProtein (g)n (g)
Fat Fat
(g)(g)Carbo-Carbo-hydrathydrat
ee
(g)(g)
CalciuCalciumm
(mg)(mg)
Iron Iron
(g)(g)Vit AVit A
(mg)(mg)Vit CVit C
(mg)(mg)
cabbagcabbagee
leafleaf
carrotcarrot rootroot
orangeorange fruitfruit
peapea seedseed
potatopotato tubertuber
soyasoya bean bean seedseed
wheatwheat seed seed graingrain
Class of food (all values per 100g of edible food
1.5
0.7
0.8
6.0
2.1
41.0
11.7
0
23.9
1.7
0
0
0
0
5.8
10.7
20.1
13.5
69.6
8.5
5.4
65.0
50.0
42.8
14.2
7.1
210.7
35.7
1.0
0.7
0.3
1.7
0.7
7.1
3.9
0
2
0
0
0
0
0
60.2
6.1
50.1
25.0
17.8
0
0
Possible consequences to man and other animals of a reduction in the variety of species
Ecological loss
Tropical rain forest
Loss of rainforest due to logging
Plantations e.g. pineapple
Destruction of the rainforest leads to loss of habitat
Tropical rain forests cover 6% of Earth’s land
They are estimated to contain half or more of all existing species of plants, animals and micro-organisms
When cleared, the ecosystem and its wide variety of interdependent species are lost forever
For every plant species that becomes extinct through man’s activities, several animal species that were dependent on the
plant for food and habitat are threatened and may become extinct
Animals nearing extinction
Brazil’s muriqui monkey
Kagu bird of New Caledonia
Birdwing butterfly of Papua New Guinea
Possible solutions
‘debt-payment-for-nature’ exchange
donations from conservationists being used to settle developing countries’ international debts
in exchange for
binding promises that these countries will create permanent reserves of tropical rain forest
Loss of future applications of plants Medicinal plants
More than 40 species of flowering plants have already provided mankind with medicines
Tropical rain forests are the Earth’s main source of plants containing chemicals of possible medicinal use in the future
It is thought that at least 2000 different plant species may contain anti-cancer properties
Most of these plants have not been studied in detail
Clearing rain forests and the subsequent loss in the variety of species means losing forever these plants and their potential
medicinal value in combating disease
Genetic storehouse
Over 70% of present day American maize plants are genetically identical
If a new disease arrives they could all be affected
American Maize Plants
A wild form of maize has been discovered in Mexico that is perennial and is resistant to many diseases
Mexican Maize plants
Geneticists are trying to introduce these useful characteristics into modern maize by cross-breeding
In future it will not be possible to introduce new beneficial characteristics into crop plants from wild varieties if they are lost by people destroying their habitats for quick commercial gain
It is essential that we conserve a wide variety of strains of each plant species to provide a genetic storehouse
Specialised uses of plants
Edible oils from plants
Olive oil Corn oilSunflower oil
Specialised uses of plants
The rape plant is a member of the cabbage family.Its leaves provide forage for farm animals such as sheep.Its tiny black seeds contain oil used in lubricants, metal tempering, and foodstuffs
Rapeseed oil
Specialised uses of plants Cotton
A cotton seed bears a mass of ‘hairy’ fibres which act like a parachute during wind dispersal of the seed
A group of seeds with their fibres entangled in a fibrous mass is called a cotton boll
The seeds are separated from their fibres
Oil and protein for animal feed are extracted from the seeds.
The fibres are spun (twisted to give strength) into yarn (thread)
The yarn is then woven into cloth (cotton)
Cotton is a cheap, hardwearing absorbent material. It is particularly useful for mixing with synthetic fibres to make a wide variety of useful fabrics
many uses
alginates
Large brown seaweed
filmforming
gellingand
binding
emulsifyingand
stabilising
thickening
toothpasteshampoo
Hand creamIce cream
polishemulsion
paint
jellytabletsdental
impressions
sausage casings
transparentfilm
washable wall
papers