Wednesday, January 19, 2011

Adaptation - Group 2

1)How do mangrove plants such as Avicenna obtain oxygen when their roots are buried in the mud?

  • The plants have physically developed their roots exposed to the air
  • Avicennia have Pneumatophores have their buried root system growing outward from the centre. From the lines here, they grow vertical roots in various heights.
  • Other species like Rhizopora, Bruguiera and Ceriops form branched aerial roots, from the lower branches of the tree. They are called stilt roots.

2)How are xerophyts adapted to survive prolonged drought?
  • They have mechanisms to prevent water loss, or to store water in their leaves.
  • They store water in their stems or leaves, to reduce water loss to a minimum.
  • Some examples of Xerophytes are; Cacti and Agaves.

3) How do polar bears survive in regions where temperatures are constantly freezing?
  • Polar bears are insulated by two layers of fur that help keep them warm
  • Their compact ears and small tail also prevent heat loss. In fact, polar bears have more problems with overheating than they do from the cold—especially when they run.
  • Polar bear feet are covered with small bumps called papillae to keep them from slipping on ice.

4)How do deep-sea anglerfish locate its prey in darkness?
  • There is a piece of dorsal spine that protrudes above their mouths like a fishing pole
  • The pole is tipped with a lure of luminous flesh
  • This built-in rod baits prey close enough to be snatched.

5) a)Why can't a saltwater fish survive in freshwater aquarium?
  • Most salt water fish would die
  • Some fish and salmon can move freely between both types of water at certain stages of their lives due to the special mechanisms of excretion and absorption of salt and water.
  • If you put a freshwater fish into saltwater, most fish would lose water and eventually die.
  • This water loss is due to diffusion and osmosis
  • Approximately 2% of all 21000 species of fish actually move from freshwater to saltwater or from saltwater to freshwater

b) What are the differences in pH between seawater and freshwater ponds

  • pH of fresh water is 7, while pH of sea water is between 7.3-8.2

Done by: Chan Tse Tzang, Chong Jun Hao, Christian Lim, Ethan soh

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