Thursday, January 20, 2011

Adaptation - Group 3

Question 1 (Johanan):

1. How do mangrove plants s
uch as Avicennia obtain oxygen when their roots are buried in the mud?
- They have “snorkels” called pneumatophores, which are aerial root specialized for gaseous exchange.- They have far reaching aerial roots for structural support and to be able to capture more oxygen.
- They are tolerant to high salinity waters.- Most have hairs on their under side of their leaves.


Question 2 (Niklaus

2. How are xerophytes adapted to survive prolonged drought?

Stomata suken in pits create local humidity/decreases exposure to air currents

— cuticle is thick and it is composed of a waxy substance that prevents water lo
ss through the epidermis.

— Fewer stomata decreases transpriation
— The needle-like leaves reduce the surface area from which water can evaporate.


Question 3 (Seeto):

3. How do polar bears survive in regions where temperatures are constantly freezing?
Question :How do polar bears (Ursus Maritimus) survive in regions where temperatures are constantly freezing?
  • In order to survive in temperatures of up to -45 degrees Celsius, Polar bears have an insulation of a thick fur coat to trap heat
  • The polar bear’s black skin absorbs heatfrom the sun, to help it stay warm
  • It possesses a fat layer that can reach a thickness of 11cm
  • Fat layer acts as an energy reserve in times of low food availability
  • Having compact ears and a small tail also helps to prevent heat loss
  • Polar bear feet are covered with small bumps to keep them from slipping on the slippery ice

Sources :
Question 4 (Jia Le):
4. How do deep-sea anglerfish locate its prey in darkness?

- Have a fleshy movable structure resembling a fishing pole that serves as a lure to attract prey

- Dangles the ray (makes its own light), in front of its mouth, in the dark

- The fish (prey) only notices the fin ray; the anglerfish quickly gobbles it

Source: &

Question 5 (Tim):

Why can't saltwater fish survive in freshwater aquarium?
What are the differences in pH between seawater and freshwater ponds?

- It is the salt in the water

- Due to the known process of osmosis water flows from areas of low salinity to high salinity areas
Freshwater and saltwater fish (taken from

- In the case of salt water fish species there is more salt in the water than in the fish

- Thus saltwater species will lose water to their enviro
nment and constantly have to drink water to preserve the balance and stay healthy

- Thus salt water fish species are very different from freshwater species

- Freshwater fish need to rid the body of excess water and salt water fish species need to rid the body of excess amounts of salt in order to be in harmon
y with the environment

- Saltwater fish actually need to work harder to maintain harmony within the environment

- But some fish can live in both freshwater and saltwater, like salmon

The saltwater pH is 8.0± and the freshwater pH is between 6.5 and 8.0.


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