Std12th Bio Pract Part B Spotting No11
11. Study of morphological adaptations of animals, found in xeric and aquatic conditions or habitats.
Date: / /202
Aim:- Study
of two animals each found in xeric (desert) and aquatic conditions (habitats)
with respect to their morphological adaptations.
Desert
animals show adaptations for conservation of water and to deal with extreme
diurnal temperature fluctuations.
1. Camel
(Camelus spp):
It is a
xerocoles animal adapted to the desert conditions. It can tolerate wide range
of temperature fluctuations.
It excretes
concentrated urine in order to conserve water.
It
accumulates fat in the hump so that heat flows away from the body and inward
flow of heat is prevented.
Camel can
even close its nostrils to stop blowing sand from entering nostrils. It is a
two-toed ungulate showing presence of hooves instead of claws on the feet. Flat
and wide feet help it to walk easily over soft sand.
It is
capable of drinking large volume of water (about 100 liters) in a short time
(about10 minutes).
It has long
eye-lashes that protect eye from sand dunes/ strong winds.
Fig. 11.1 : Camel
2. Kangaroo
rot (Dipo,iomys spp):
It is a xerocoles rodent. It is nocturnal in habit to avoid heat of the day and to have humid air inside. It seals its burrow during daytime to prevent the loss of moisture. It obtains metabolic water and has the ability to derive hygroscopic water from dry seeds which it eats. Kangaroo rat neither sweat-nor pant to keep itself cool.
Adaptations of animals found in aquatic conditions (habitats).
Aquatic animals show special adaptations for aquatic habitats.
1. Fre h water fish Rohu (Labeo rohito):
1. Body is laterally compressed and streamlined in order to
minimize resistance of water and
thus to reduce friction with water.
ii. It shows presence of gills for respiration which help in
exchange of gases in water.
iii. Paired fins help in swimming and caudal fin acts as
steering during swinning (i.e. changing
direction).
iv. Body is covered by scales to prevent osmotic entry of water
into the body.
v. Labeo is ammonotelic
2. Dolphin (Delphinus spp):
i. It is a mammal and not a fish.
Caudal fin
ii. It has streamlined, smooth and furless body to reduce
friction.
iii. It has a backward curving dorsal side and dorsal fin. Snout
is beak like.
1v. The position of nostrils near the top of the head,
facilitates easy breathing when animal reaches
the surface of water for breathing.
v. Flippers in dolphin can control for steering, slowing and going
up or down or out of water.
Questions
1. Enlist morphological adaptations in desert animals.
Answer - The desert animals are poikilotherms,
i.e., they can match their internal temperature to the external.
They excrete
nitrogenous waste in the form of uric acid.
The animals
stay in burrows to avoid water loss from the body and excrete highly
concentrated urine.
The body
temperature of camels increases by 7℃ during the late afternoon that
decreases the heat flow from the environment. The fur reduces the heat gain
from the environment.
Thus these
adaptations help them to conserve water as much as possible and prepare them to
live without water if required.
2. Enlist the morphological adaptations in aquatic animals.
Answer - They inhale oxygen through their gills or
skin. Marine mammals have lungs and have to come to the surface to breathe They
are cold-blooded, i.e., their body temperature is the same as the surrounding
environment. The collapsible lungs and rib cages help them to withstand very
high water pressures.The aquatic animals at great depths are bioluminescent,
i.e., they emit light to attract preys and mates.They have the property of
osmoregulation, i.e., the fish can maintain an internal environment of salt and
water.
3. Give functions of
a. Hump
Answer - The humps function the same way—storing fat which can be converted to water and energy when sustenance is not available. These humps give camels their legendary ability to endure long periods of travel without water, even in harsh desert conditions. As their fat is depleted, the humps become floppy and flabby.
d. Caudal fin
Answer - The caudal fin is the primary appendage which is used for locomotion in many fishes. The caudal fin is also known as tail fin or a median fin which is usually homocercal or heterocercal. Generally, it is a vertically expanded structure which is located at the caudal end of the body. The base of the caudal fin is known as caudal peduncle with strong swimming muscles. In general, caudal fin acts like a propeller while the caudal peduncle functions as a motor
4. Enlist cursorial adaptations in desert animals.
Answer - Desert animals get away from the sun's heat by digging underground burrows.They have massive hind legs, that allow the Kangaroo Rat to jump nine feet at a time, allowing it to escape fast and sneaky animals.
4. Study of flowers adapted to pollination by differentpollinating agencies (Wind and Insects)
PART B Question No 04 Spotting Practical Experiment No 3
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7. Study of meiosis in onion flower bud with the help of permanent slides.
6. Study of T. S. testis, T. S. ovary and V. S. of blastula, through permanent slides.
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