Thursday, January 20, 2011

Adaptation - Group 3

Avicennia and
 its pneumatophores
1) How do mangrove plants such as Avicennia obtain oxygen when their roots are buried in the mud?

- The tree has pencil-like pneumatophores (roots specialized for gaseous exchange) to obtain oxygen.
- They stick up above the ground from underground roots that spread out from the trunk.


Cactus, an example
 of a xerophytes
2) How are xerophytes adapted to survive prolonged drought?

- Have spines that shade the plant from the sun and collect moisture.
- Have extensive shallow root systems that are usually radial (arranged like radii of a circle; diverging in lines from a common center), allowing for the quick absorption of water when it rains.
- Store water in the core of both stems and roots
- Eliminate leaves or reduce leaf size to eliminate transpiration.
- Have waxy skin on stems to seal in moisture.


Wide, large paws
 of a polar bear
3) How do polar bears survive in regions where temperatures are constantly freezing?

- Have a layer of blubber under its skin which helps it stay warm. It also has two thick layers of fur.
- Have white fur helps them blend in with the snow and ice to hunt prey.
- Have small ears and tails help to prevent heat loss.
Have furred feet that help insulate it against cold and provide for traction on the slick, iced surfaces. They also have small bumps called papillae on their feet that further keep them from slipping on ice.
- Have an acute sense of smell that helps it locate its prey even when it is hidden or camouflaged in drifts of snow or ice.


Anglerfish, with its lure at the front.
4) How do deep-sea anglerfish locate its prey in darkness?

- It uses its lure, which emits light to attract its prey.
- While remaining motionless, it waves its lure back and forth, and waits for the prey to come closer to its mouth. 


- The dark skin of the anglerfish absorbs this light and doesn't reflect it, so it remains invisible in the inky blackness, waiting for prey to go after its lure.


5a. Why can't a saltwater fish survive in freshwater aquarium?

- Salt water fish’s tissues are likely to be a little less salty than its environment and the problem is going to be holding on to the water in its body. As a result, saltwater fish have kidneys that can make really concentrated urine, and may have ways to secrete extra salt.
- The fish’s body is set up to cope with one set of conditions it can't easily adjust to the other set.

5b. What are the difference in pH between seawater and freshwater ponds?

Freshwater should have a pH between 6.5 and 7.5 while saltwater slightly more alkaline than freshwater, with an acceptable range between 7.8 and 8.3.

Done by: Daniel, Jit Sheng, JingHeng, Wen Kai and Zhang Bo

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