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It's us

Class 3e1
Though we're small in numbers but we have big powers!
List of people

Bio assignment due on 27JAN
Name of people who had completed will be bold.

Allie ; April ; Crystal ; Denise ; Indira ; Saranya ; Sheryl ; Jesslyn ; Siauxin ; Yunji ; Huiming ; Ruelia ; Peizhen ; Dingheng ; Weesiang ; Zhengguang ; Weixhan ; Weikai ; Issac ; Fengye

P/S: Click on your name, your post will appear.



PICTURE PICTURE

First ever bio trip.






Linkage

Allie
Crystal
Sheryl
Jesslyn
Huiming
Lau Wee Siang


What happened?

January 2010
February 2010

Thanks

Blogskins.com
LSX


} ARE FEATHERS A LIVING OR A NON-LIVING THING?
Thursday, January 28, 2010 @ 7:01 PM


Are feathers living or non-living things?

But before I elaborate on the main point, let me introduce some facts about feathers. Feathers are important to birds as they provide warmth to the birds and it also helps them to mate and communicate with each other.

So, what are feathers made up of? The feathers are mostly made of keratin which is a tough but flexible protein that is manufactured by the skin cells. KERATIN is also a very light yet strong material. There are different types of feathers like Tail, Semiplume or Downy feathers.

Sample of a feather and its features.

So, are feathers alive? The answer given by many of the scientists are “NO”.

The feathers are dead tissues. They are only alive while developing as they have a blood supply. Feathers are produced by living cells located in small pit-like follicles in a bird's epidermis, its outer skin layer.

The feather is enlarged by the keratin that is protruding straight out from the skin follicle. The feather is dead as soon as it reaches a full size body because the blood supply to the shaft is cut off and the shaft base stiffens. It is also considered dead as it has neither innervations nor a blood supply. The feather is now a fully functional, but non-living structure.

So what happens to the feathers after a long time? They molt. A mature feather is not a living feather so damage or wear on a feather cannot be repaired.

So they go through this process – molting whereby they will replace the whole feather or a large portion of the feather with new feathers. Molting usually occurs when there is nothing major is going on in a bird’s life, like before or after migration or nesting. Molting also takes place systematically, like only a certain part of the feathers will molt first to ensure that the bird can still fly.

As feathers fall out, new ones called pin feathers take their place. They are the living feathers with a blood supply inside them. As the new pin feather matures, a thin sheath of keratin covering protects the pin feather. As the feather continues to mature, the blood supply will dry up and the keratin cover will fall off or be preened off to reveal a new feather.

Even though the scientist and the authors of the sources provided think they are non-living, I beg to differ. I think that they are living things. In a living thing, they should meet the 8 criterias: Movement, Excretion, Irritability/Sensibility, Growth, Reproduction, Adaptability and Nutrition.

Even though the feathers do not excrete or take in nutritions, they still move, they still grow and reproduce.

A feather has 23 functions. Examples would be to trap air to keep the bird warm, they can even control to what certain length they want to spread out their wings. When their old feathers die out, new ones grow back again. The feathers can even trap air. Even though feathers do not have nerves, they do stimulate nerves that surround where the feather attaches to the bird. Birds can adjust the position of their feathers and posture depending on the stimulation of the nerves which shows that they have the irritability/sensibility. Even after the old feathers have molted, the new ones still grow back, still reproduce and grow to a certain size.

So, though the feathers do not take in nutrition or excrete, they meet the rest of the criteria. Like, they can move the feathers to enable them to fly, which meets the movement criteria. Birds can adjust the position of their feathers and posture depending on the stimulation of the nerves which shows that they have the irritability/sensibility and adaptability. The feathers also grow up to a certain size which meets the "Growth" criteria. When its time for molting, they reproduce the feathers, new feathers grow, which meets the "Reproduction criteria." Also, they have so many functions. Though the scientists say that the feathers are non-living things, they WERE once a living thing when there was blood supply to them.

Therefore, I think that feathers are living things.

Resoucrces

http://askabiologist.asu.edu/research/bird_feathers/

http://www.earthlife.net/birds/feathers.html

http://www.treeswallowprojects.com/cfeather.html


April(3)