Thursday, January 20, 2011

Adaptation - Group 2


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

- Mangrove roots have develop the aerating component. The above ground parts of the root system will enable the plants to allow the gas exchange process.

- Through root hair and their capillary passages, the absorption of water and nutrients occur, even in anaerobic soil condition. The movement of nutrients through the vessels and from the substrates is controlled by the osmotic system.

- Though the system has a high selectivity for nutrient uptake, as it is a high saline environment, the nutrient uptake may contain higher salt than required. The excess salt will then transported to excretive glands such as those located in the leaves.

- Some older plants built big and strong descending prop roots, sometimes exceeds 3 meters high, as buttresses to support the plants.

Source :

2. How are xerophytes adapted to survive prolonged drought?

Definition of xerophytes: A plant adapted for growth under dry conditions.

How are xerophytes adapted to survive prolonged drought?

- Xerophytes usually have few, or no, leaves thus reducing transpiration

- Extensive shallow root systems that allow for quick absorption of water

  • Ability to store water in the core of both their stems and roots
  • Waxy skin to seal in moisture
  • Spines on the cactus shade the plant and collect moisture
  • They shed leaves during a drought


3. How do polar bears survive in regions where temperatures are constantly freezing?

  • Has white fur made of hollow hairs, which traps and warms air.
  • Ultra-violet light is funneled from the sun down the hairs to the bear’s black skin, changing it into warmth.
  • Dense undercoat is covered with an outer coat of long guard hairs (these help to keep the polar bear dry and warm while it is swimming)
  • A thick layer of blubber, up to 11 cm thick, keeps the polar bear warm while swimming in cold water.


  • Dug very carefully under the snow drifts
  • They dig out a smaller den above the entrance, ensuring that the warm air in these rooms cannot escape.
  • Thickness of the roof: is around 75 centimeters to two meters
  • Roof acts as a good insulator to keep the heat in
  • Temperature outside: –30 degrees
  • Temperature in den: never below 2 or 3 degrees
  • During hibernation, the metabolic rate of the mother bear slows down to save energy, thus enabling the cubs to be better nourished.


  • they are so well insulated that they tend to overheat
  • To avoid this, they move slowly and rest often they also swim to cool down on warm days or after physical activity.
  • Heat is also released through areas where fur is absent.



4. How do deep-sea fish anglerfish fish locate its prey in darkness?

- The deep-sea anglerfish lives at depth of over 3,000 feet where there is almost no light and the water is near freezing.

- Deep-sea anglerfish has a blue-green light, waving it back and forth to attract its prey.

- It has a specialized spine that is highly maneuverable and can be moved in any direction to catch its prey.

- It will remain completely motionless until the prey gets close enough, then the angler fish snaps it up with its powerful jaws and swallows it whole.

- When a male and a female anglerfish fuse, the male anglerfish relies on the female anglerfish for its nutrition.


5. Why can’t a seawater fish survive in freshwater aquarium?

When you separate two sets of solutions by a semi-porous membrane like that around a cell water can move in and out but large molecules like sugars, proteins and salt cannot. Nature likes balance. If one of the solutions on one side of the membrane is saltier than the other, the solutions seek balance. Since the salt can't move the water from the less salty solution moves out into the more salty one to try to balance it.

  • A fresh water fish your cells are saltier than the water you live in and so water constantly flows into your body. To survive you will need super efficient kidneys to pee out the extra water and methods to collect whatever salts you can to replace those lost in all that pee.

  • A salt water fish you have the opposite problem. Your tissues are likely to be a little less salty than your environment and your problem is going to be holding on to the water in your body (remember fish in the ocean don't have access to a nice drink of fresh water to replace what they lose). As a result, saltwater fish have kidneys that can make really concentrated pee, and may even have ways to secrete extra salt.


Done by: Michelle, Davina, Naveena, Stacey, Gwendolyn.

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