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What kind of exoskeleton is present in the members of class—Osteichthyes?
In the members of Osteichthyes (bony fishes) skin is covered by exoskeleton made of large cycloid scales impermeable to water. They reduce osmotic water loss in marine environment and entry of water in fresh environment.
In the members of Osteichthyes (bony fishes) skin is
See lesscovered by exoskeleton made of large cycloid scales
impermeable to water. They reduce osmotic water loss in
marine environment and entry of water in fresh
environment.
Which special features help fishes to sense their environment ?
Fishes have following sense organs to sense their external environment. (i) Ear is formed of only one internal ear having three semicircular canals. (ii) Olfactory sacs (nasal chambers) do not open in buccal cavity as internal nares are absent. (iii) Lateral line sensory system is present to note thRead more
Fishes have following sense organs to sense their
See lessexternal environment.
(i) Ear is formed of only one internal ear having three
semicircular canals.
(ii) Olfactory sacs (nasal chambers) do not open in buccal
cavity as internal nares are absent.
(iii) Lateral line sensory system is present to note the
changes in surrounding water.
Describe the respiratory system of birds.
Birds respire through lungs (pulmonary respiration). The lungs have air sacs which help in double respiration and act as an internal cooling agents. Sound producing organ is syrinx (at the base of trachea) and larynx has no vocal cords.
Birds respire through lungs (pulmonary respiration). The
See lesslungs have air sacs which help in double respiration and
act as an internal cooling agents. Sound producing organ
is syrinx (at the base of trachea) and larynx has no vocal
cords.
List two terrestrial adaptations of reptiles.
Terrestrial adaptations of reptiles are mentioned below (i) Epidermal scales forming exoskeleton. (ii) Shelled and cledoic egg.
Terrestrial adaptations of reptiles are mentioned below
See less(i) Epidermal scales forming exoskeleton.
(ii) Shelled and cledoic egg.
List out some freshwater and some marine bony fishes.
Freshwater bony fishes Labeo, rohita, Catla catla, Cirrhina mrigala, Cyprio corpio. Marine bony fishes Hilsa, Harpodon, Stromateus.
Freshwater bony fishes Labeo, rohita, Catla catla,
See lessCirrhina mrigala, Cyprio corpio.
Marine bony fishes Hilsa, Harpodon, Stromateus.
All vertebrates are chordates, but all chordates are not vertebrates. Justify the statement.
All chordates have a notochord, but only in vertebrate the vertebral column develops from notochord, so all chordates are not vertebrates. All vertebrates are chordates as they have notochord in embryonic stage.
All chordates have a notochord, but only in vertebrate
See lessthe vertebral column develops from notochord, so all
chordates are not vertebrates. All vertebrates are
chordates as they have notochord in embryonic stage.
There has been an increase in the number of chambers in heart during evolution of vertebrates. Give the name of the class of vertebrates having two, three or four-chambered heart.
(i) Two-chambered heart—Pisces (ii) Three-chambered heart—Amphibians and reptiles except crocodiles (iii) Four-chambered heart—Crocodiles, aves and Mammalia.
(i) Two-chambered heart—Pisces
See less(ii) Three-chambered heart—Amphibians and reptiles
except crocodiles
(iii) Four-chambered heart—Crocodiles, aves and
Mammalia.
Birds have no teeth, then how do they grind the grains they eat as food?
Birds have food storing crop and food masticating gizzard, which helps them to grind the food.
Birds have food storing crop and food masticating
See lessgizzard, which helps them to grind the food.
Why pneumatic bones are present in birds?
The empty space in pneumatic bones helps in weight reduction of skeleton in birds. It is a kind of flight adaptation in birds.
The empty space in pneumatic bones helps in
See lessweight reduction of skeleton in birds. It is a kind
of flight adaptation in birds.
Why are urochordates called tunicates?
This is because the soft body of urochordates is surrounded by a thick test or tunic, often transparent or translucent.
This is because the soft body of urochordates is
See lesssurrounded by a thick test or tunic, often
transparent or translucent.