Eds bio

[serene syeda!]

ECOSYSTEM

The interaction of plants & animals as they exist in nature are part of an ecological system. An ecosystem may be an edge of a pond, a pool, an ocean or a closed bottle containing some algae and protozoans. It is affected by physical or biological factors.


PHOTOSYNTHESIS

Photo – light, synthesis – building up

It is the process of synthesis of carbohydrates by the green plants in the presence of light, water, CO2 & chlorophyll (green pigment) with the subsequent release of oxygen.
This process is the fundamental difference between plants & animals.
Animals get their food from the plants while most of the plants prepare their own food.
The overall reaction is:
6CO2 + 6H2O C6H12O6 + 6O2
sunlight
This process provides us with food & oxygen.



HUMAN EAR

Human body has two ears, which serve as organs of hearing.
Human ears are hear sound waves between frequencies of 20 – 20,000 Hz.
Each ear has following parts:
Outer ear
Middle ear
Internal ear


Outer ear:
has outer flap of cartilage covered by skin called Pinna & a tube that leads inwards called External Auditory Meatus, which has sebaceous glands that produce secretions. External auditory meatus ends at the ear drum, a membranous structure.

Middle ear: From the ear drum inwards is middle ear, an air filled cavity which communicates with nasal cavity through a tube called Eustachian tube. Middle ear also has three bones; incus, malleus & stapes (smallest bone of the body).

Internal ear: has coiled cochlea, supplied by the auditory nerve, making it sensitive to the sound waves. Through this nerve the signals are sent to the brain.Internal ear also has three semicircular canals, utricles & succulus, concerned with the maintaining balance & posture.