Page 113 - Science Class 07

Excre on in Earthworm

In earthworms, nephridia cons tute the
excretory organs. These are coiled tubes which
throw wastes into the intes ne of the
earthworm or directly to the outside, in the
form of urea and ammonia.

A Pa ent on Dialysis

Earthworms feed from the soil. The excreta
Aim : To test the presence of glucose in discharged by the earthworms is very useful
urine. for the plants. It works as an organic

Method : Take a small quan ty of urine in a fer liser and do not cause any harm to our
test tube and add benedicts solu on to it. environment.
Now, heat this solu on ll it gets boiled.
Now, let the solu on to cool down. If red Excre on in Insects (Cockroach)
brick precipitate is found in the solu on, In insects, the excretory system cons tutes a
then you should take it as the sample of bunch of long tubules called malpighian
urine contains glucose.
tubules. The wastes inside insects’ body
contain mainly uric acid which is discharged
EXCRETION IN OTHER ANIMALS
along with faeces.
The mechanism of excre on varies from
animal-to-animal. In desert animals, excretory
mechanism helps them conserve water while
the excretory system in aqua c animals helps
them to discharge heavy amount of the water.

Let’s study about the mechanism of excretory
Cockroach
system of different animals:
Excre on in Fishes
Excre on in Amoeba
Freshwater fish must overcome the problem
Amoeba is a unicellular organism. It lives in
fresh water. Waste products, which mainly posed by water entering the body through
osmosis salts leaching out. For this, they
contain ammonia, gets out of its body through
Swim
the process of diffusion or with the help of bladder Dorsal fin Adipose fin Caudal
(characteris c fin
contrac le vacuole. Brain Spinal cord of trout)
Nos rl

Cut edge Anal fin
of operculum Liver
Gills Heart Anus Lateral line
Kidney Stomach Gonad Urinary bladder
Intes ne
Pelvic fin
Amoeba Exretory System in a Fish

Science-7 113