Animal Morphology MCQ Quiz - Objective Question with Answer for Animal Morphology - Download Free PDF

The correct answer is the Lungs.

• The main respiratory organ of the whale is the lung.

Key Points

• Whales and dolphins are mammals and breathe air into their lungs, just like we humans do.
• They cannot breathe underwater like the fish can as they do not have gills for that.
• They breathe through nostrils, called a blowhole, located right on top of their heads.

Additional Information

• Blowholes are a physical feature of whales and dolphins characterized by a muscular hole on the top of their heads.
• Whenever the whales reach the water surface, the blowhole opens and it blows air out and in.
• While blowing out air, it can cause the water to spray which is called the spout.
• When underwater, the muscles around the blowhole ensure that it stays closed. 

The correct answer is Three.

Key Points

• Amphibians, such as frogs and salamanders, have a three-chambered heart.
• The heart consists of two atria and one ventricle.
• The three-chambered heart allows for some separation of oxygenated and deoxygenated blood.
• This structure is an evolutionary adaptation suited to their dual life in water and on land.

Additional Information

• Oxygenation Process:
  • In amphibians, the heart pumps both oxygenated and deoxygenated blood, which partially mixes in the single ventricle.
  • This mixed blood is then sent to the lungs and skin for oxygenation and to the rest of the body.
• Circulatory System:
  • Amphibians have a double circulatory system, with separate pulmonary and systemic circuits.
  • This system is more efficient than a single circulatory system but less efficient than a four-chambered heart.
• Comparison with Other Vertebrates:
  • Fish have a two-chambered heart (one atrium and one ventricle).
  • Birds and mammals have a four-chambered heart (two atria and two ventricles), which allows for complete separation of oxygenated and deoxygenated blood.
• Evolutionary Significance:
  • The three-chambered heart of amphibians represents an intermediate stage in the evolution of the more complex hearts of higher vertebrates.
  • This adaptation is essential for amphibians' survival in both aquatic and terrestrial environments.

The correct answer is Rhinoceros.

Key Points

• Infrasound refers to sound waves with frequencies below the lower limit of human audibility, typically below 20 Hz.
• Rhinoceroses are known to communicate using infrasound, which can travel long distances and penetrate obstacles.
• Infrasound is used by rhinoceroses for various purposes, including communication over long distances and detecting environmental cues.
• Other animals known to use infrasound include elephants and whales, which use it for communication and navigation.
• Humans cannot hear infrasound, as our hearing range is typically between 20 Hz and 20 kHz.

Additional Information

• Humans
  • Humans can hear sound frequencies in the range of 20 Hz to 20 kHz.
  • Sounds below 20 Hz are considered infrasound, and sounds above 20 kHz are considered ultrasound.
• Bats
  • Bats use echolocation to navigate and hunt, which involves emitting ultrasonic sounds (above 20 kHz) and listening for the echoes.
  • They have a highly developed auditory system to detect these high-frequency sounds.
• Dolphins
  • Dolphins use a form of echolocation similar to bats but operate primarily in the ultrasonic range.
  • They can produce and hear sounds in a wide frequency range, including ultrasonic frequencies used for communication and hunting.

Correct Answer ​Cilia

Key PointsParamecium

• Paramecium is also a unicellular organism which lives in water and moves with the help of cilia.

Euglena

• Euglena is an unicellular animal which moves with a flagellum.

Additional Information Amoeba

• We know Amoeba is an unicellular organism.
• It does all the activities like digestion, locomotion, respiration and reproduction within the same cell.

The Correct answer is Support.

Key Points

• The notochord is a flexible, rod-shaped structure that provides support to the body of chordates, especially during their embryonic stage.
• It forms the primary axis of the body and acts as a scaffold for the development of the vertebral column in vertebrates.
• The notochord is located between the digestive tube and the nerve cord and is composed of cells derived from the mesoderm.
• In most vertebrates, the notochord is replaced by the vertebral column during development, but it still plays a crucial role in body structure and organization during early embryogenesis.
• The presence of a notochord is one of the primary characteristics of the phylum Chordata, which includes all vertebrates, cephalochordates, and urochordates.
• In species like amphioxus (lancelets), the notochord persists throughout life, providing continuous support and structural integrity.
• The notochord is also significant for inducing the development of the neural tube, which later forms the central nervous system, including the brain and spinal cord.

Additional Information

• Locomotion
  • While the notochord provides structural support, it does not directly aid in locomotion. Instead, locomotion in chordates is facilitated by structures like muscles and fins or limbs.
  • In some aquatic chordates, the notochord works in conjunction with muscles to allow a wave-like motion for propulsion.
• Digestion
  • The notochord is not involved in the process of digestion. Digestion is carried out by the digestive system, which includes organs like the stomach, intestine, and associated glands.
  • The digestive tube in chordates lies below the notochord.
• Respiration
  • Respiration in chordates is facilitated by specialized structures like gills, lungs, or skin, depending on the species and their habitat.
  • The notochord does not play a role in gas exchange or respiration.

The correct answer is the Lungs.

• The main respiratory organ of the whale is the lung.

Key Points

• Whales and dolphins are mammals and breathe air into their lungs, just like we humans do.
• They cannot breathe underwater like the fish can as they do not have gills for that.
• They breathe through nostrils, called a blowhole, located right on top of their heads.

Additional Information

• Blowholes are a physical feature of whales and dolphins characterized by a muscular hole on the top of their heads.
• Whenever the whales reach the water surface, the blowhole opens and it blows air out and in.
• While blowing out air, it can cause the water to spray which is called the spout.
• When underwater, the muscles around the blowhole ensure that it stays closed. 

The correct answer is Platyhelminthes.

Key Points

• Phylum Platyhelminthes belongs to the kingdom Animalia.
• The organisms are also known as flatworms.
• These are acoelomates and they include many free-living and parasitic life forms.
• They have a single opening in their digestive system that serves both as a mouth and an anus.
• Platyhelminthes have the following important characteristics:
  • They are triploblastic, acoelomate, and bilaterally symmetrical.
  • They may be free-living or parasites.
  • The body has a soft covering with or without cilia.
  • Their body is dorsoventrally flattened without any segments and appears like a leaf.
  • They are devoid of the anus and circulatory system but have a mouth.
  • They respire by simple diffusion through the body surface.
  • They have an organ level of organization.
  • They do not have a digestive tract.
  • The space between the body wall and organs is filled with connective tissue parenchyma which helps in transporting the food material.
  • They are hermaphrodites, i.e., both male and female organs are present in the same body.
  • They reproduce sexually by fusion of gametes and asexually by regeneration by fission and regeneration. Fertilization is internal.
  • The life cycle is complicated with one or more larval stages.
  • They possess the quality of regeneration.
  • The flame cells help in excretion and osmoregulation.
  • The nervous system comprises the brain and two longitudinal nerve cords arranged in a ladder-like fashion.

Explanation:-

A single-celled creature, also known as a unicellular organism, is an organism made up of only one cell.
Yeast-

• Yeasts are unicellular creatures that originated from multicellular ancestors, with certain species able to generate multicellular traits by generating pseudohyphae or fake hyphae, which are strings of connected budding cells.
• Yeast diameters vary significantly depending on species and environment, although most yeasts are 3–4 µm in diameter, with some reaching 40 µm.
• Mitosis is used by most yeasts to reproduce asexually, and many of them use the asymmetric division process known as budding to accomplish it.

Bacteria-

• Bacteria are minute, single-celled organisms that can be found in large numbers in all environments, both within and outside of other organisms.
• Some bacteria are hazardous, but the majority are beneficial.
• They are utilised in industrial and therapeutic activities, and they support many forms of life, both plant and animal.

Amoeba-

• An amoeba, also known as an amoeboid, is a type of cell or single-celled creature that can change its shape by extending and retracting pseudopods.
• Amoebae are found in every major lineage of eukaryotic species and do not belong to a single taxonomic category.
• Amoeboid cells can be found in fungus, algae, and mammals, in addition to protozoa.

The correct answer is Filament, hook and basal body.

Key Points

• Bacterium Flagella
  • Bacterial flagella are made of the protein flagellin and are a coiled, thread-like structure with a sharp bend and a rotary motor at the base.
  • It gives bacteria the ability to swim freely through a binary compound of aqueous, also known as motility or self-propulsion.
  • It is composed of three major structural elements;
    • Basal body
      • It is joined to the cytoplasmic membrane and cell membrane.
        It is made up of rings that are surrounded by MotB proteins.
    • Hook
      • A hook is a name for the wider area at the base of the flagellum.
      • It connects the filament to the base's motor protein.
    • Filament
      • It is a thin, hair-like structure emerging from the hook.

Additional Information

• The long, helical filament of bacterial flagella is made up of several flagellin subunits organised in a variety of tangled chains.
• A flagellum is made up of numerous parts and rotates, similar to a boat motor's propeller.
• Depending on the species, the diameter of bacterial flagella varies, which lies between 15 and 20 nm.
• Functions of Bacterial Flagella
  • Role in pathogenesis
  • Organ of locomotion
  • Role in identification of organism

Crocodiles have a four-chambered heart.

• Adaptation to their maximum portion of the life cycle is done in water since they need to minimize the oxygen loss when submerged and the four-chambered hearts decrease the heartbeat by 2-3/minute and normalize this rate when the crocodile is above water.
• The crocodile may have the most complex circulatory vertebrate system.
• This has a four-chambered heart and two ventricles, an uncommon characteristic between the current reptiles, and both the left and the right aorta, which are connected by a hole called the Panizza Foramen.
• Crocodiles belong to Crocodylidae family.

The correct answer is Spiracles.

Key Points

• The respiratory system of cockroaches:
  • ​The respiratory system of the cockroach consists of a network of the trachea, that opens through 10 pairs of small holes called spiracles present on the lateral side of the body.
  • Thin branching tubes (tracheal tubes subdivided into tracheoles) carry oxygen from the air to all the parts. air enters the body through spiracles.
  • When air through external openings, enters into its respiratory system, spiracles serve as muscular valves paving the way to the internal respiratory system. The respiratory organ of the cockroach is referred to as the tracheae.
  • The trachea is a dense array of a network of air tubes found in the internal system.
  • Tracheae are known to balance the pressure inside the system.
  • When oxygen-rich air enters the body of the cockroach via spiracles into the tracheal tubes, it diffuses into various tissues and cells of the body. Here, oxygen is used up to liberate energy.
  • Likewise, carbon-dioxide rich air passes into the trachea and moves outwards through the spiracles.
  • Carbon dioxide is given out as a result of the respiratory process.

The Correct Answer is Bat.

 Key Points

• Nocturnality is an animal behavior in which the animal remains active during the night and sleeps during the day.
• These creatures generally have highly developed senses of hearing, smell, and specially adapted eyesight.
• Owls, Bats, Hedgehogs are some examples of nocturnal animals.

The correct answer is Tracheae

Key Points

• Most insects respire through a system of tubes called tracheae that connect to the air via spiracles that can be actively opened or closed. 
• In insects, the tracheal tubes primarily deliver oxygen directly into the insects' tissues. 
• There is the main pair of lateral tracheae running the length of the body, one on each side.

Additional Information

The correct answer is Thyroxin.

Key Points

• Thyroxin hormone (TH) is the most important hormone in frog metamorphosis.
  • The thyroid gland secretes thyroxine (TH), a hormone essential for the growth and development of all vertebrates including humans.

Additional Information

• Metamorphosis is a biological process that involves sudden and abrupt changes in the body structure of the animal by cell growth and differentiation.
  • It is generally observed in amphibians and insects.
• Adrenaline
  • It is produced in the centre (medulla) of the adrenal glands and some neurons of the central nervous system.
  • The overall effect of adrenaline is to prepare the body for the fight or flight response in times of stress, i.e. for vigorous and/or sudden action.
• Insulin
  • It is secreted in the pancreas.
  • It allows your body to use glucose for energy.
  • Once glucose is in your bloodstream, insulin causes cells throughout your body to absorb the sugar and use it for energy.
• Testosterone
  • Testosterone is a hormone found in humans, as well as in other animals.
  • In men, the testicles primarily make testosterone.
  • Women’s ovaries also make testosterone, though in much smaller amounts.
  • Testosterone is most often associated with sex drive and plays a vital role in sperm production.
  • It also affects bone and muscle mass, the way men store fat in the body, and even red blood cell production.

The correct answer is Large number of cone cells.

• Cone cell is used to see the colour.
• It is present in the central part of the retina.
• Cone cells are very sensitive to low light.
• A large number of protons are required to trigger the cone cell.
• Cone cells also help in a photopic vision.
• So large numbers of cone cells help to see very well in the day.

Additional Information

• Rod cells and cone cells are two types of photoreceptor cell found in the retina.
• Rod cells are photoreceptor cells in the outer edge of the retina of the eye.
• Rod cells are more sensitive to light than cone cells and they are also in huge amount.
• The human eye contains about 130 million rods and about 7 million cone cells.
• Rhodopsin is made up of a protein called opsin which is a photosensitive chemical derived from vitamin A.​