GLOBAL WARMING AND POLLUTION

NEWS: Global warming and pollution are stripping vibrant colours from nature: Ecological discolouration — large-scale changes in the colours of oceans, forests, plants, insects, birds, and corals

Changes observed globally

• Oceans turning greener: Over 50% of oceansà have become greener in the last 20 years
  • Reason: Increase in phytoplankton and algal blooms, warming waters + nutrient pollution
• Forests are experiencing: Premature leaf browning, Stress from heat, drought, and deforestation
• Living organisms have colours for: Camouflage, attracting mates, thermoregulation, predator avoidance
  • As environments change–>natural selection favours different colours

Evidence from scientific studies

• Amazon butterflies & deforestation: Deforestation reduced brightly coloured butterfly species
• Less colourful butterflies: Camouflage better, survive in disturbed habitats
• During the Industrial Revolution: Soot darkened tree bark, darker peppered moths survived better
• Coral bleaching: India specific exampleà Gulf of Mannar, Palk Bay, Lakshadweep, Andaman & Nicobar Islands, Gulf of Kachchh

Ecological “rules” explaining colour change

• Bogert’s Rule (cold-blooded animals)
  • Animals in cold climates → darker
  • Animals in warm climates → lighter
  • Helps regulate body temperature
• Gloger’s Rule (warm-blooded animals)

Animals in:

• Humid, rainy regions → darker
• Dry, cold regions → lighter