Diversity in The Living World MCQ Quiz - Objective Question with Answer for Diversity in The Living World - Download Free PDF

The correct answer is a poikilotherm

Explanation:

• Animals are often classified based on their ability to regulate body temperature. This classification determines whether their body temperature remains constant or fluctuates with environmental conditions.
• Poikilotherms are animals whose body temperature varies with the temperature of their surroundings. Unlike homeotherms, they do not maintain a constant internal body temperature. Organisms like amphibians, reptiles, and fish are common examples of poikilotherms as they rely on external heat sources to regulate their body temperature.
• Homoeotherm: These are animals that maintain a constant internal body temperature, regardless of environmental conditions. Examples include mammals and birds. 
• Ectotherm: While ectotherms also rely on external sources of heat for body temperature regulation, this term primarily refers to the source of heat rather than the fluctuation in body temperature.
• Endotherm: These are animals that generate internal heat through metabolic processes to maintain a stable body temperature. Examples include humans, cats, and dogs.

The correct answer is Cloaca

Explanation:

• During embryonic development in frogs, a structure called the blastopore forms. The blastopore is an opening that connects the archenteron (primitive gut) to the external environment.
• In deuterostomes like frogs, the blastopore develops into the cloaca, which is a common cavity for the intestinal, urinary, and reproductive tracts.

Other Options:

• Mouth: The blastopore does not develop into the mouth in frogs. Instead, the mouth forms separately from the stomodeum during embryonic development.
• Nasal Pore: Nasal openings develop independently to connect the nasal cavity to the external environment.
• Gonopore: Gonopores are specific openings for gamete release in certain organisms, but in frogs, reproductive openings are part of the cloaca.

The correct answer is 2nd and 3rd thoracic segments

Explanation:

• Insects are members of the class Insecta, characterized by their segmented bodies, jointed appendages, and exoskeleton.
• The body of an insect is divided into three main segments: head, thorax, and abdomen.
• The thorax is the central segment of the body, and it plays a crucial role in locomotion as it supports both wings and legs in flying insects.
• Flying insects typically bear wings only on the 2nd and 3rd thoracic segments (mesothorax and metathorax).
• The mesothorax typically supports the forewings, while the metathorax supports the hindwings.
• These wings are crucial for flying and are supported by strong muscles within these thoracic segments.
• Examples include butterflies, bees, and dragonflies, where the wings are attached to the 2nd and 3rd thoracic segments.

The correct answer is Crocodiles

Explanation:

• The foramen of Panizza is a unique anatomical feature found in the heart of crocodilians, a group that includes crocodiles, alligators, caimans, and gharials.
• This structure is a small opening or channel that connects the left and right aortae near the base of the heart.
• It plays a crucial role in regulating blood flow and allows crocodiles to efficiently manage oxygenated and deoxygenated blood circulation, especially during diving or when submerged underwater.

Fig: Crocodile heart

Key Points about the Foramen of Panizza:

• The foramen of Panizza is not found in other groups of animals, making it a distinctive feature of crocodilian anatomy.
• This structure allows for the mixing or bypassing of oxygenated and deoxygenated blood. During diving, crocodiles can redirect blood flow to prioritize oxygen delivery to essential organs like the brain and heart while reducing blood flow to the lungs.
• Crocodiles are often submerged for extended periods. The foramen of Panizza enables them to conserve oxygen and remain underwater for longer durations.

The correct answer is Longitudinal ciliated groove on the ventral wall of the pharynx of Amphioxus.

Explanation:

• The endostyle is a key anatomical feature found in certain chordates, particularly in primitive species such as Amphioxus (a cephalochordate) and larval forms of tunicates.
• It is a longitudinal ciliated groove located on the ventral wall of the pharynx. Its main function is to produce mucus and aid in trapping food particles during filter feeding.
• In evolutionary terms, the endostyle is considered homologous to the thyroid gland in vertebrates. This evolutionary link is supported by the fact that both structures share a role in iodine metabolism.
• The endostyle secretes mucus, which captures small food particles suspended in water as the organism filters it through its pharyngeal slits.
• The cilia lining the endostyle help in moving the mucus-bound food particles toward the digestive tract for further processing.

Fig: Amphioxus (Internal structure)

Other Options:

• Stylus in the endoderm of the intestine – This is incorrect because the endostyle is not a stylus (rod-like structure) and is not located in the intestine. It is specifically a ciliated groove in the pharynx of chordates.
• Crystalline style in mollusca – This is incorrect because the crystalline style is a structure in mollusks, particularly in bivalves, that aids in digestion by releasing enzymes to break down food. 
• An endodermal derivative in the coelom – Endostyle is of endodermal origin, it is not located in the coelom (body cavity).

The correct answer is a - iv, b - iii, c - ii, d - i.

Key Points

• Blue-green Algae (Cyanobacteria)
  • Blue-green algae are actually bacteria and are also known as Cyanobacteria.
  • They are photosynthetic organisms and can live in a wide variety of environments, including freshwater, seawater, damp soil, or rocks.
  • Cyanobacteria are known for their significant contribution to the Earth's oxygen atmosphere.
  • They can exist as single cells or can form colonies.
• Red Algae (Rhodophyta)
  • Red algae, often called Rhodophyta, have been identified as one of the oldest groups of eukaryotic algae.
  • They are mostly found in the warmer waters of the ocean.
  • Red algae are of great economic value because of their use in the production of agar and carrageenan, substances used as thickening agents in various food products.
  • Their red colour is due to the pigment, phycoerythrin.
• Green Algae (Chlamydomonas)
  • Green algae are a diverse group of algae from which plants evolved. Chlamydomonas is a genus of unicellular green algae.
  • Chlamydomonas species are widely distributed worldwide and are found in soil and freshwater.
  • They have two flagella that allow them to move.
  • They are known for their green colour due to the presence of chlorophyll.
• Brown Algae (Sargassum)
  • Brown algae are the most complex type of algae; many are seaweeds.
  • Sargassum is a brown algae, known for forming massive floating forests in the ocean.
  • It is primarily marine and is found in warm-temperate and tropical oceans.
  • They provide important ecological functions such as providing habitats for a wide variety of marine species.
  • The brown colour is due to the presence of a pigment called fucoxanthin, which masks the green colour of chlorophyll.

The correct answer is Collar cells.

 Key Points

• The body of sponges (poriferans) has several minute pores called ostia through which the water enters into the central cavity, spongocoel.
• The flagellated cells called choanocytes (collar cells) line the spongocoel.
• These cells generate a flow of water and the water current helps in food gathering, respiratory exchange and removal of waste.
• The water finally goes out of the body through a large pore called osculum. (Plural: oscula).
• The body wall of the sponge is composed of two layers: outer pinacoderm and inner choanoderm. In between these two layers, mesenchyme is present with various mesenchymal cells.

Additional Information

• Somatic cells make up the connective tissue, skin, blood, bones and internal organs.
• White blood cells are made in the bone marrow. They are stored in your blood and lymph tissues.
• These sex cells are also called reproductive cells or gametes. Sperm cells are produced in men's testicles and egg cells are produced in women's ovaries

The correct answer is Rhodophyceae.Key Points

• Red algae:-
  • It is a type of marine algae that are predominantly red in color due to the presence of pigments such as phycoerythrins and phycocyanins.
  • They are found in both tropical and temperate waters and play an important role in marine ecosystems as primary producers and as a food source for herbivorous marine animals.
  • Some species of red algae are also used by humans for various purposes such as food, medicine, and cosmetics.
  • Red algae are known for their ability to survive in extreme environments such as deep-sea hydrothermal vents and polar regions.

Additional Information

• Chlorophyceae:
  • This is a class of green algae that are mostly freshwater species and are commonly found in ponds, lakes, and streams.
• Liverwort:
  • This is a type of non-vascular plant that grows in damp habitats such as forests, bogs, and riverbanks.
  • They are commonly found in temperate and tropical regions and play an important role in soil formation and nutrient cycling.
• Phaeophyceae:
  • This is a class of brown algae that are predominantly marine and are commonly found in temperate and cold waters.
  • They are important primary producers in coastal ecosystems and are also used by humans for food and other purposes.

The correct answer is Marchantia.Key Points

• Liverworts:-
  • These are non-vascular plants that belong to the phylum Hepatophyta.
  • The umbrella-shaped structures that raise gametangia above the main gametophyte body are known as archegoniophores.
  • These archegoniophores are found in the genus Marchantia.
• Marchantia:-
  • It is a genus of liverworts, which are a type of non-vascular plant often found in moist and damp environments.
  • Liverworts belong to the division Marchantiophyta and are some of the earliest land plants to have evolved.
  • Marchantia liverworts are small, flat, and leafy plants that typically grow in low, spreading mats.
  • They have a distinctive appearance with flattened, lobed structures that resemble tiny leaves.

Additional Information

• Polytrichum:-
  • It​ also known as haircap moss, is a type of moss that forms dense cushions or tufts in moist habitats.
• Funaria:-
  • It​ is also known as cord moss, is a common type of moss that is found in moist, shaded habitats.
• Sphagnum:-
  • It is  also known as peat moss, is a type of moss that is found in wetlands and bogs and is known for its ability to store water.

Concept:

• There are innumerable species of plants and animals and other organisms inhabiting the surface of the earth.
• To identify and study these species, it is necessary to develop a mechanism that has a universal application.
• Different life forms are identified and classified into different groups which helps in their study.

Explanation:

Different Systems of Classification - 

• Two Kingdom System of Classification:
  • Carl Linnaeus divided all the life forms present on the earth into two groups based on their mode of nutrition.
  • He gave the two Kingdom System which includes - Kingdom Plantae and Kingdom Animalia.
  • However, this system of classification was inadequate due to the vast majority of organisms found on earth.
• Five Kingdom System of Classification:
  • R.H. Whittaker proposed the Five Kingdom System of Classification.
  • According to R.H. Whittaker's Five Kingdom system, the living organisms are divided into the following Kingdoms - 

•    Kingdom Monera includes unicellular prokaryotic organisms. Eg: Pseudomonas
• Kingdom Protista includes unicellular eukaryotic organisms. Eg: Euglena
• Kingdom Plantae includes multicellular eukaryotic organisms. Includes autotrophs, semi-autotrophs, and insectivorous plants.
• Kingdom Fungi include multicellular eukaryotic organisms (except for yeast which is unicellular). These are mainly heterotrophs. E.g.- Saccharomyces cerevisiae
• Kingdom Animalia includes multicellular eukaryotes that are heterotrophs. These organisms have adapted to holozoic nutrition. E.g.- Human beings

So from the above-given information, the correct answer is option 1.   

The correct answer is Species.

Key Points

• Species are the fundamental classification unit.
  • A Species is a group of organisms with similar Morphologies that are capable of Mating.
  • The Basic unit of Classification and Taxonomic order for an individual in biology is a species, which is also a part of Biodiversity.
  • Species is the largest group of creatures in which any two compatible Partners, typically through sexual reproduction, can produce fertile offspring.
  • A Species can also be distinguished by its karyotype, DNA sequencing, outward appearance, behavioral patterns, and ecological niche. Because it is impossible to assess the development of fossils, paleontologists also use the chronospecies concept.
  • All species, with the exception of viruses, have a two-part name called a "binomial." The first part is the genus to which the species belongs.

Additional Information

• Bacteria, Archaea, Protozoa, Chromista, Plantae, Fungi, and Animalia are the 7 different kingdoms.
  • A Genus is a taxonomic category ranking used in biological classification that is below family and above species.

The correct answer is i - b, ii - a, iii - d, iv - c. Key Points

• Chlorophyceae:-
  • It is a class of green algae, distinguished mainly on the basis of ultrastructural morphology.
  • They are usually green due to the dominance of pigments chlorophyll a and chlorophyll b.
  • The chloroplast may be discoid, plate-like, reticulate, cup-shaped, spiral- or ribbon-shaped in different species.
  • Most of the members have one or more storage bodies called pyrenoids located in the chloroplast.
  • Pyrenoids contain protein besides starch. Some green algae may store food in the form of oil droplets.
• Phaeophyceae:-
  • It also known as brown algae, is a class of multicellular algae that are found primarily in marine environments.
  • They are distinguished by their brown color, which is due to the presence of the pigment fucoxanthin.
  • Brown algae range in size from microscopic filaments to giant kelp forests that can reach over 60 meters in length.
• Cyanophyceae:-
  • It is known as Cyanobacteria, is a class of prokaryotic organisms that obtain energy via photosynthesis.
  • It is known as Blue-green algae.
  • They are considered to be the oldest form of life on Earth, with fossils dating back over 3.5 billion years.
  • Cyanobacteria are found in a wide variety of habitats, including freshwater, marine, and terrestrial environments.
• Rhodophyceae:-
  • It also known as red algae, is a class of eukaryotic algae that are found primarily in marine environments.
  • They are distinguished by their red color, which is due to the presence of the pigment phycoerythrin.
  • Red algae range in size from microscopic filaments to large, complex seaweeds.

The correct answer is Platyhelminthes.Key Points

• Platyhelminthes are also known as flatworms.
• Flatworms have unsegmented, bilaterally symmetrical, soft bodies, with a triploblastic construction (comprising three layers of cells) and a lacking coelom, skeleton, and anus.
• Example includes Planaria, Liver fluke (Fasciola hepatica), and Tapeworm.

Additional Information

• Cnidaria includes jellyfish, corals, and sea anemones.
  • They have radial symmetry, a single body opening, and stinging cells called cnidocytes.
• Ctenophora includes comb jellies.
  • They have radial symmetry and cilia for movement but also have a complete digestive system.
• Porifera includes sponges.
  • They have asymmetrical or radial symmetry, no true tissues, and filter food through pores in their bodies.

The correct answer is Aschelminthes. Key Points

• ​Roundworms are the popular name for Aschelminthes.
• They are distinguished by having a pseudocoelom.
• They either live freely or are parasites.
• They can be found on plants, animals, humans, and even in freshwater and soil.
• In the human intestine, Ascaris is discovered to exist as an endoparasite.
• The body is triploblastic and bilaterally symmetric.
• The body is long, slender, and not segmented; it tapers out at the end.
• There is no evidence of metameric segmentation.
• Males are often smaller than females since they are dioecious.
• Their bodies are organised on an organ-system level.​

Additional Information

• Platyhelminthes:
  • The flatworms, also known as platyhelminths, are a phylum of soft-bodied, relatively uncomplicated bilaterian invertebrates.
  • They are bilaterally symmetrical, triploblastic, and acoelomate.
  • They could be parasites or free-living beings.
• Ctenophores:
  • Sea waters are home to a phylum of marine invertebrates known as comb jellies, or Ctenophora.
  • They have two embryonic layers, the ectoderm and endoderm, making them diploblastic.
  • They lack a bodily cavity since they are acoelomates.
  • Ctenophores are symmetrical in all directions.
• Mollusca:
  • After Arthropoda, Mollusca is the second-largest phylum of invertebrate animals.
  • Organ system level organization can be seen in them.
  • A cavity exists in their body.
  • The skull, visceral mass, muscular foot, and mantle are the different parts of the body.
  • Tentacles and complex eyes make up the head.
  • The body has a calcareous shell covering it.