Life Sciences essays for Grade 10, 11 and 12 (South Africa):

List of Life Sciences essays for Grade 10, 11 and 12

NEPHRON ESSAY

Essay Question: Write a short essay explaining the homeostatic functioning of the nephron if a person is suffering from dehydration

Life Sciences essays for Grade 10, 11 and 12

When the water content of the body drops below normal, the following happens

  • the osmotic potential of the blood increases √  
  • which stimulates the osmoreceptors in the hypothalamus √
  • which produces ADH
  • to transmit impulses to the pituitary gland (hypophysis) √
  • to release more ADH √ in to the blood
  • ADH is transported by bloodstream to the kidney √ where this hormone increases the permeability √ of the walls of the distal convoluted tubule and collecting duct √
  • more water √ is re-absorbed from the filtrate √
  • and small amount of concentrated urine √ is excreted
  • the adrenal gland √ secrete aldosterone √ which cause sodium ions √ to be actively √ pumped out of the filtrate √ in the ascending limb of loop of Henle √ in to the tissue fluid of the kidney medulla √
  • this creates a low water potential √ and water moves by passive osmosis √  from the collecting tubule √  in to the tissue fluid of the medulla √ from where it is absorbed in to the blood capillaries √

ECOUTOURISM ESSAY

Essay Question: Write a mini essay on ecotourism in South Africa using the following guideline

  1. Brief explanation of what ecotourism entails,
  2. Long term sustainability and Possible threat to Ecotourism 

Ecotourism

  • Ecotourism is mainly inclined to promote environmental awareness and instil asense of appreciation of natural formations and beauty.
  • It makes people respect the existence of other living organisms (fauna and flora) that shares the resources of the planet earth
  • Its main clients are people who are interested in preserving the environment.
  • A potential ecotourist prefers to spend his/her holidays in a natural environment to experience and be part of the environment
  • They like to visit and spend time in quiet natural settings such as unspoiled beaches, river mouths, waterfalls, wet lands with lush green forests, gorges,mountains etc.
  • Always prefer to use eco-friendly mode of transport to cause less pollution and damage to fauna and flora
  • Encourages people to consume naturally grown, fresh produce from the area
  • Greater emphasis is placed on the well-being of local people and constantly look for ways and means to contribute towards the local economy
  • Eco-friendly accommodation is provided for visitors to minimise the possible human impact on the surrounding area
  • Renewable energy is utilised wherever possible

Long term sustainability

Educate the local population about the importance of conserving the natural resources.

  • The involvement of the local community should be prioritised.•
  • Active participation generates income for local communities. e.g. selling composts, organic food products.
  •  Job creation alleviates poverty. e.g. tour guides, security personnel, and creating opportunities to sell and exhibit art work.
  • Ownership of the concept leads to proper caring and protection of the fauna and flora. e.g. prevention of poaching, illegal smuggling of exotic animals and plants, discourages over exploitation of natural resources.
  • Part of the income generated can be utilised for conservation and rehabilitation projects.
  • Cementing strong partnership with the private and public sector could provide more management and financial support

Possible threats to ecotourism

  • Poaching / illegal hunting
  • Crime and violence against tourists
  • Pollution
  • Illegal trade of exotic plants and animals
  • Illegal occupation of land and the establishment of squatter camps
  • Natural disasters. e.g. wild fires, droughts, floods, etc.
  • Deforestation• Extension of farming lands
  • Illegal dumping of waste
  • Illegal developments e.g. hotels and golf estates, airports, stadia. etc.
  • Building of dams in an ecologically sensitive area
  • Miningo Exploitation of tourists

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