Mention four significant services that a healthy forest ecosystem provide.

OR

Substantiate with the help of one example that in an ecosystem mutualists (i) tend to co-evolve and (ii) are also one of the major causes of biodiversity loss.

Healthy forest ecosystems provide various services. Some of those are listed below.

• Purification of air and water
• Mitigation of droughts and floods
• Nutrient cycling
• Generation of fertile soil
• Maintenance of biodiversity, etc.
  
  OR
   

i) The Mediterranean orchid Ophrys employs ‘sexual deceit’ to get pollination done
by a species of bee. If the female bee’s colour patterns change even slightly for any reason during evolution, pollination success will be reduced unless the orchid flower co-evolves to maintain the resemblance of its petal to the female bee.

ii) In the case of a coevolved plant-pollinator mutualism (fig tree and wasps), extinction of one invariably leads to the extinction of the other. Thus, co-evolution is a cause of biodiversity loss.