Seeds (8) Flashcards
All life on earth depends on plants. Plants are the basis of _____ in which all animals, including humans, live, survive and grow.
ecosystems
It is thought that _______ to 100 000 plant species are currently under threat.
60 000
What are the root causes of the plant species being under threat? (2)
- human population growth
- socio-economic factors
What is a seed bank?
In modern terminology, a seed bank is a facility used to store seeds of various wild plants and crops, in an effort to maintain biodiversity.
The MSBP works together with, amongst others, the South African National Biodiversity Institute. South Africa’s aim is to contribute seed of about 2 500 of its indigenous species to the MSBP, focusing on: (3)
− endangered species − endemic species
− species that might become endangered due to over-exploitation.
How do seed banks help to maintain biodiversity?
Seed banks can be of great help to maintain biodiversity by offering protection against loss of species in the wild.
Plant diversity has been negatively affected by many factors such as:
- habitat loss (e.g. because of agriculture, development of cities, building of dams, large-scale ecological disasters, etc.)
- climate change
- over-exploitation of certain species. To help maintain biodiversity, the high quality seed from the seed banks can be used to produce plants for the:
- re-establishment of damaged or destroyed habitats and ecosystems.
- re-introduction of newly extinct, endangered or threatened species back into the environment.
- production of plant material, as a source for research of over-exploited plants. This is far better than over-exploiting wild populations, which could lead to them to become endangered or extinct.
Of the six major plant parts, seeds are the most important ____ of human food. The other five major plant parts are roots, stems, leaves, flowers and fruits. A great variety of species have edible seeds, mostly from flowering plants (angiosperms)
source
Why are seeds important? (2)
- have great food value.
* are a very practical source of food as they are easy to transport and store well for long periods.
Plants with edible seeds have been cultivated since ancient times and commonly fall into three groups: (3)
- Grains (cereals), from grass-like plants, e.g. maize, wheat, rice, oats
- Pulses (legumes, e.g. lentils, peanuts), from pea and bean plants
- Nuts – any large, dry, oily seeds found within a hard shell and used as food
The food stored in these seeds can be used: (2)
- directly as food, e.g. rice, oats
- for the manufacture of human food products, eg cooking oil from crushed sunflower seeds and baking flour from milled wheat, rice etc.
Why are grains and pulses so important? (3)
- form the staple diet of most of the world’s diet
- have a high nutritional value
- are cheap
Why are grains important? (4)
- a rich store of starch
- fibre
- Most of the vitamin B vitamins and many minerals
- small amounts of proteins and fats
What is the importance of pulses? (2)
- a very good source of protein, minerals and vitamin Bs
- help regulate blood sugar levels
What is the importance of nuts? (3)
- a very good energy source
- rich in monounsaturated or polyunsaturated fatty acids
- supply one of the best natural resources of vitamin E
