Tuesday, January 18, 2011

Adaptation Group 5

1. How do mangrove plants such as Avicennia obtain oxygen when their roots are buries in the mud?

The Avicennia is a plant living in mangrove swamp. As the mud of mangroves has a very low oxygen content, A. marina has roots that grow vertically from the ground called Pneumatophores to obtain oxygen. Pneumatophores have loosely packed tissues to allow effective diffusion of gases into the pith.

When the root is covered by water, the root does not allow water or air to enter, when the tide recedes, air is sucked in.

Adaptations of mangrove trees to the environment (http://ecology.hku.hk/jupas/Mangrove/adaptations.htm)

2. How are xerophytes adapted to survive prolonged drought?
Xerophytes are plants that are adapted to a dry environment.
Specialized tissues: for storing water, example the cactus which is able to store water in it's stem.
Leaves: reduced to spines, to minimise water loss through transpiration. They often also have abundant stomata to maximize gas exchange during periods in which water is available.

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

Fur: thick, oily fur coats and a layer of blubber to insulate the heat in their bodies.

Special feet: that allows them to walk properly on the ice and snow without slipping and falling.

Large teeth and claws: to prevent its prey from escaping as food is scarce in the Arctic regions.

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

The angler fish lives at depth so deep that there is virtually no light at all.

The angler fish uses a rod-like structure which is actually a fin ray. It emits light which attracts prey in the darkness. The prey is attracted to the light and as the prey swims closer, the angler fish will gobble up the prey.

5. Why can't a saltwater fish survive in freshwater aquarium? What are the differences in pH between seawater and freshwater ponds?
A salt water fish is not able to adapt to the low salinity of freshwater. The salinity of salt water helps salt water fish to be able to survive.
Salt water: 8.0 pH
Fresh water: 5.5 pH and 7.5pH

Done by: Dionne, Jing Jie, Zong Wei, Kai Xuan

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