Edexcel A (SNAB) A Level Biology:复习笔记4.2.10 Sustainability & Plant Materials

• Sustainability refers to the using resources in such a way that the requirements of the current generation are met without depleting these resources for future generations
• This requires the use of renewable resources - which can be used without the resource running out
  • An example would be solar energy - it will not run out in our lifetime as the sun will continue to shine every day for several billion more years
• Fossil fuels are an example of a non-renewable resource, as they could potentially run out if we use them too fast (since it takes millions of years for fossil fuels to form)
• Sustainable practices are those that minimise the damage done to the environment and its resources, to ensure that there will be something left for the next generation
  • An example would be replanting trees after logging
• Unsustainable practices are limited by a finite supply of resources
  • An example is the use of fossil fuels to make oil-based plastics

Plant fibres and Sustainability

• Using plant fibres to make products such as ropes and fabric is more sustainable than using oil-based plastics
• Less fossil fuels are used and plants can be replanted for the next generation
• Plant fibres are biodegradable, unlike most oil-based plastics, which means the products made from these fibres can be broken down by microbes to minimise environmental pollution
• Extracting and processing oil is an expensive and difficult procedure compared to growing and processing plants, making plant-based products easier and cheaper to produce in developing countries
• However, the ropes made from plant fibres are typically not as strong as plastic ones

Starch and Sustainability

• Plants store excess sugars as starch in their cells
• Starch can be used to make bioplastics which is more sustainable than making oil-based plastics
• It does not require as much fossil fuels to be burned to produce them and the crop plants can be replanted (renewable resource)
• Starch can also be used to make bioethanol, which can be used as a fuel for vehicles
• Using starch to produce biofuels is more sustainable than producing them from oil