Diversity of Life Forms MCQ Quiz - Objective Question with Answer for Diversity of Life Forms - Download Free PDF

The correct answer is The presence of a network of water-filled tubes for movement.

Explanation:

• The absence of sexual reproduction: This is not a distinguishing feature because both Echinoderms and Cnidarians are capable of sexual reproduction. While there are variations in their reproductive strategies, both groups utilize sexual reproduction as a means to propagate their species.
• The presence of radial symmetry: This feature is shared by both Echinoderms and Cnidarians. Cnidarians (such as jellyfish and sea anemones) exhibit radial symmetry, typically in the form of a basic radiate symmetry. Echinoderms (such as starfish and sea urchins) also exhibit a type of radial symmetry, usually pentaradial symmetry in adulthood.
• Having a central cavity involved in digestive processes: Both Echinoderms and Cnidarians have a cavity that plays a crucial role in their digestive system. In Cnidarians, the gastrovascular cavity (sometimes simply called the coelenteron) is a central cavity in which digestion takes place, and it also helps distribute nutrients throughout the organism's body. It has a single opening that functions as both mouth and anus. Echinoderms, while having a more complex digestive system including separate mouth and anus in many forms, also possess internal cavities that serve various functions including digestion. Their digestive system includes a stomach and intestine, and they have internal water vascular systems that support their physiological processes, which includes nutrient distribution.
• The presence of a network of water-filled tubes for movement: This feature is exclusive to Echinoderms. Echinoderms possess a unique water vascular system, which is a network of water-filled canals that aid in locomotion, feeding, and gas exchange. The system includes structures such as tube feet (or podia), ampullae, and the madreporite. This system allows for complex movements and is a defining characteristic of the phylum Echinodermata. Cnidarians do not have such a system; they primarily rely on simple muscle contractions and passive drifting for movement.

The correct answer is (A) - (iv), (B) - (v), (C) - (i), (D) - (ii), (E) - (iii)

Explanation:

• A. Thrips - IV. Thysanoptera: Thrips belong to the order Thysanoptera. These are small insects known for their fringed wings and are often considered pests due to their ability to damage plants.
• B. Lacewings - V. Neuroptera: Lacewings belong to the order Neuroptera, characterized by their delicate, net-like wings. They are beneficial insects as their larvae feed on pests like aphids.
• C. Termites - I. Blattodea: Termites are classified under the order Blattodea, which also includes cockroaches. Termites are social insects and are known for their role in decomposing wood and plant material.
• D. Earwigs - II. Dermaptera: Earwigs belong to the order Dermaptera, characterized by their pincers (cerci) on the abdomen and elongated bodies. They are nocturnal and feed on a variety of organic matter.
• E. Stick insects - III. Phasmatodea: Stick insects, also known as phasmids, belong to the order Phasmatodea. They are known for their camouflage, resembling sticks or leaves to evade predators.

The correct answer is The syncytial theory states that multicellular organisms arose through the aggregation of free-living unicellular forms.

Explanation:

• Multicellularity is a significant evolutionary milestone that allowed for the development of complex life forms. The transition from unicellular to multicellular organisms involved mechanisms such as cell adhesion, communication, and differentiation.
• Several theories and experiments have been proposed to explain the origin of multicellularity, each focusing on different aspects of cellular organization and evolutionary processes.
  • ​The syncytial theory does not state that multicellular organisms arose through the aggregation of free-living unicellular forms. Instead, it posits that multicellularity evolved from a single multinucleated cell (syncytium) that eventually developed into multicellular organisms through the compartmentalization and cellularization of its nuclei. The aggregation of free-living unicellular forms is actually associated with the colonial theory, not the syncytial theory.

Other Options:

• The "snowflake yeast" experiment demonstrated the evolution of multicellularity through mechanisms such as cell adhesion and programmed cell death. In this experiment, unicellular yeast evolved multicellular traits under selective pressure, showcasing how simple multicellular structures can emerge in laboratory conditions. This statement is correct.
• Cadherin-based adhesion pathways played a crucial role in the evolution of multicellularity, but this is specific to animals, not plants. In plants, multicellularity evolved through different mechanisms such as plasmodesmata. 
• Co-option of existing functions is a well-supported hypothesis for the evolutionary transition from undifferentiated multicellular clusters to differentiated tissues. For example, genes initially involved in unicellular processes were repurposed to support multicellular organization. This statement is correct.

The correct answer is (E) - (iii), (C) - (v), (D) - (i)

Concept:

Microbial identification involves the use of specific stains to differentiate microorganisms or their components based on their structural properties. The correct matching of microbes or their components with the respective stains is crucial for accurate identification and diagnosis. Below is the explanation for the correct and incorrect matches:

• Albert stain: Used specifically for staining volutin granules in Corynebacterium diphtheriae.
• Ziehl-Neelsen stain: A specialized acid-fast stain used for identifying acid-fast bacteria like Mycobacterium leprae and Mycobacterium tuberculosis.
• Lactophenol cotton blue: Commonly used for staining fungal structures, making it ideal for cultured fungi.
• Silver stain: Used for staining delicate structures like flagella or certain fungal components.
• India ink: Used for demonstrating capsules in certain bacteria, such as Klebsiella.
• Malachite green: Typically used for staining bacterial endospores, such as those found in Clostridium.
• Gram stain: A differential stain used for classifying bacteria as Gram-positive or Gram-negative.

Explanation:

• (E) Cultured fungi - (iii) Lactophenol cotton blue: Fungi are best stained with lactophenol cotton blue, which highlights their structural details such as hyphae and spores. This match is correct.
• (C) Pseudomonas flagella - (v) Silver stain: Flagella are delicate structures that can be visualized using silver stain. This is the correct match for Pseudomonas flagella.
• (D) Volutin granules of C. diphtheriae - (i) Albert stain: Albert stain is specifically used to highlight metachromatic granules (volutin) in Corynebacterium diphtheriae. This match is correct.

The correct answer is (A) - (II), (B) - (III), (C) - (I), (D) - (IV)

Explanation:

• Bird migration is a seasonal movement of birds between breeding and wintering grounds. Migratory birds travel long distances to find favorable climates, adequate food sources, and breeding grounds.
• India is a significant destination for migratory birds due to its diverse ecosystems and moderate climate during winters.
• Some prominent migratory birds visiting India include Black-tailed Godwit, Comb Duck, Ruff, and Spotted Redshank. These birds migrate from specific regions around the globe.
  • Black-tailed Godwit (A): Black-tailed Godwits have extensive breeding grounds across northern Eurasia, including Russia and parts of Scandinavia. Russia is a very significant origin for Black-tailed Godwits that migrate to India.
  • Comb Duck (B): Comb Duck migrates from Madagascar and South Asia (Region III). This duck is commonly found in freshwater habitats in India during its migration period.
  • Ruff (C): Ruffs are well-known migratory waders that breed extensively in the Arctic and sub-Arctic tundra zones of Eurasia.
  • Spotted Redshank (D): This bird migrates from Scandinavia (Region IV). It is known for its elegant appearance and is commonly sighted in Indian wetlands during its migratory journey.

The correct answer is Option 4 i.e.Brugiya malayi

Concept:

• Filariasis is a parasitic disease caused by the spread of roundworms belonging to the Filarioidea type.
• These parasites are spread via mosquitoes or other blood-feeding insects.
• This disease is found in subtropical regions (hot, humid, and damp regions) such as South Asia, South Africa, the South Pacific, and parts of South America.
• Humans are their definitive hosts.

• Depending on the major affected areas of the human body, this disease is categorized into:
  • Lymphatic filariasis
  • Subcutaneous filariasis
  • Serous cavity filariasis

Explanation:

Option 1: Listeria monocytogenes

• It is a pathogenic bacteria that causes listeriosis.
• It is usually transmitted by contaminated food.
• It causes serious infection and severely affects pregnant women and older people.
• Hence, this option is incorrect.

Option 2: Cryptococcus neoformans

• This is an encapsulated yeast-like fungus that causes cryptococcal meningitis.
• It is life-threatening only in immunocompromised patients like AIDS patients.
• Hence, this option is incorrect.

Option 3: Francisella tularensis

• It is a gram-negative bacteria that causes tularemia.
• It is a zoonotic pathogen that causes febrile conditions in affected person.
• In this disease, the affected person suffers from respiratory troubles like cough and breathing problems.
• Hence, this option is incorrect.

Option 4: Brugiya malayi

• It is one of the filarial nematodes that causes lymphatic filariasis in humans.
• The Mansonia and Aedes mosquitoes are the known vectors for this nematode species.
• They are exclusively found in south-east Asia.
• Hence, this option is correct.

Hence, the correct answer is Brugiya malayi.

Concept-

• The gymnosperms (gymnos: naked, Sperma: seeds) are planted in which the ovules are not enclosed by any ovary wall and remain exposed, both before and after fertilization.
• Gymnosperms include medium-sized trees or tall trees and shrubs.
• Gymnosperms are mainly classified into two groups:
  • Cycadophyta (Lower gymnosperm)
  • Coniferophyta (Higher gymnosperm) 
• Examples of gymnosperms are cycas, ginkgo, pinus, etc.

Explanation-

• Ginkgo is a kind of tree that is considered one of the oldest living trees. 
• It dates back to 200 million ago. 
• Ginkgo is known as a living fossil because its present species have remained unchanged for the past 51 million years. This is the feature of a fossil. 
• By observing its preserved leaves and reproductive organs it was said that the Gingko's "morphology has changed little for over 100 million years". 

Therefore Ginkgo Biloba is a living fossil.

• Cedrus is known as deodar.
• Ephedrine (Medicine) is obtained from ephedra. 
• Gnetum belongs to the class Gnetales.

The correct answer is Cleistogamy and geitonogamy.

Explanation:

• Autogamy: This refers to self-fertilization, where pollen from the same flower fertilizes its ovules. This is a form of selfing.
• Allogamy: This refers to cross-fertilization, where pollen from one flower fertilizes the ovules of another flower. This promotes genetic diversity but is not selfing.
• Cleistogamy: This is a form of self-pollination that occurs in closed flowers, where the flowers do not open, ensuring that pollen from the same flower fertilizes its ovules. This is a strong form of selfing.
• Geitonogamy: This involves the transfer of pollen from one flower to another flower on the same plant. While it involves different flowers, because they are on the same plant, it is still considered a form of selfing.
• Herkogamy: This refers to a spatial separation of male and female reproductive structures to promote cross-pollination, thus reducing selfing.

Thus, the correct answer is Cleistogamy and geitonogamy as both promote selfing.

The correct answer is Trypanosoma.

Explanation-

African sleeping sickness, also known as African trypanosomiasis, is caused by protozoan parasites belonging to the Trypanosoma genus.

There are two species of the parasite that cause the disease in humans:

• Trypanosoma brucei gambiense: This is responsible for causing chronic or West African sleeping sickness, which accounts for more than 98% of reported cases. The disease progresses slowly, with patients possibly remaining asymptomatic for several months to years before symptoms appear.
• Trypanosoma brucei rhodesiense: This causes acute or East African sleeping sickness, less frequent but much more acute form of the disease. Symptoms appear within weeks or months of infection.

The parasites are transmitted to humans by the bite of an infected tsetse fly, which is native to certain parts of Africa.

• Once in the human body, the parasites multiply and invade various body tissues including the bloodstream and the central nervous system, leading to a variety of symptoms including fever, headaches, joint pain, and in severe cases, disturbances to the sleep cycle, which gives the disease its common name "sleeping sickness".

Additional Information

Plasmodium: Four species of Plasmodium parasites - P. falciparum, P. vivax, P. ovale, and P. malariae - cause malaria in humans. This disease is transmitted through the bite of an infected female Anopheles mosquito. Symptoms may include high fever, chills, flu-like symptoms, and severe illness that can lead to death.

Paramecium: Paramecium is generally not a pathogenic organism, meaning it does not cause disease in humans. It is a common organism in freshwater environments. So unlike Plasmodium, Paramecium is not known to be a causal agent for any human disease.

Amoeba: Amoeba are a broad group of protists, but when talking about disease in humans, the most relevant is Entamoeba histolytica. E. histolytica causes amoebiasis, also known as amoebic dysentery. It is an intestinal illness transmitted primarily through contaminated water or food with fecal matter, especially in areas with poor sanitation. The amoeba can invade the lining of the large intestine, leading to amoebic colitis which can present with abdominal discomfort, diarrhea, and/or bloody stools

Conclusion- Trypanosoma causes Sleeping sickness.

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

Explanation:

• Homonym: Refers to two or more specific or subspecific scientific names with the same spelling, but for different nominal taxa. Example: Carduelis carduelis (European Goldfinch) and Carduelis carduelis (Butterfly)
• Tautonym: A binomial name that contains the same epithet for both the genus and species. Example: Gorilla gorilla (Western Gorilla)
• Basionym: The original name of a taxon on which a new combination is based. Example: Poa annua (originally described; later reclassified as Cucumis melo var. flexuosus)
• Hemihomonym: When the same binominal name is given to a plant and an animal. Example: Acer pensylvanicum (Painted Maple in plants) and Acer pensylvanicum (a type of fossil Coleoptera) to a plant and an animal.

Therefore, 

• a. Homonym (iv) - Same spelling, but for different nominal taxa
• b. Tautonym (i) - Binomial name contains the same epithet for both the genus and species
• c. Basionym (iii) - Original name of a taxon on which a new combination is based
• d. Hemihomonym (ii) - Same binominal name given to a plant and an animal

The correct answer is Option 4 i.e.A - ii, B - iii, C - i, D - iv

Key Points

A. Heteroblastic -

• Heteroblastic plants are plants that exhibit distinct changes in leaf shape, size,or other characteristics as they grow from seedlings to mature plants.
• These changes can occur at different stages of their development, leading to variations in their foliage.
• It's a phenomenon commonly observed in many plant species.

B. Phanerogams -

• Phanerogams are a group of seed-producing plants that belong to the division Spermatophyta.
• They are also known as seed plants. Phanerogams are characterized by the production of seeds within specialized structures, such as flowers or cones.
• They include two major groups: gymnosperms, which produce seeds in cones, and angiosperms, which produce seeds enclosed within fruits or flowers.

C. Hemicryptophytes -

• These are a type of plant life from categorized based on their growth and survival strategies.
• They are perennial plants that have buds located close to the soil surface, often at or just below ground level.
• These buds allow the plants to regrow from the ground after winter or adverse conditions.
• Hemicryptophytes typically shows various adaptations to endure harsh environmental conditions, such as cold temperatures, drought,or grazing.

D. Hermaphrodite -

• Hermaphrodite, in biological terms, refers to an organism that has both male and female reproductive organs.
• This means that hermaphrodites are capable of producing both egg and sperms, and they have the ability to self fertilize, or they can mate with another individual of the same species to reproduce.

Corrected Table:

Hence, correct option is 4.

Concept:

• Fossils are remains of a once-living organism that is preserved by nature. 
• Complete fossils can take anywhere from 10,000 years to hundreds of thousands of years to form due to the complex process of fossilization.
• Depending upon the type of fossilization processes, unique fossils are formed. 
• Fossil types -  

1. Petrified fossils - The meaning of the word petrifaction is "turning into stones".This type of fossil is created when an organism's body parts are replaced by minerals.  Water seeps through the layer of sediments to reach the dead creature because it is rich in dissolved minerals. Only the materials that have solidified are left behind when water evaporates. Plant parts are being replaced molecule by molecule by minerals like iron, pyrites, silicates, carbonates, sulphates, etc. The cells and tissues of the plant become impregnated and impregnated with these minerals. 
2. Mold and cast -  A mold is formed when an organism's hard tissues are buried in sediment like sand, silt, or clay and over time, the hard component totally disappears, leaving a hollow space with an organism's shape. The mold is converted to cast when the hollow interior is filled with water where the mineral sediments left behind in the create a cast. 
3. Carbon films - Carbon films are formed when an organism dies and is buried in sediment and a thin layer of carbon is formed on an organism’s delicate parts like leaves or plants.
4. Trace fossils - These show the activity of an organism, for example, footprint.
5. Preserved remains - It is formed when organisms are preserved in their original form. For example, an insect trap in the tree's resin. 
6. Compression - In this type of fossil, organic remains of the plant has remained in the fossils and it shows the outline of the organism.
7. Impression - This type of fossil are just an impression of the plant on the sediment.

Explanation: 

• Aglaophyton major was first originally describes as Rhynia major by Kidston and Lang in 1920.
•  D.S. Edwards, n 1986 re-examined fossil specimens of Rhynia major and reported that actually, they did not contain true vascular tissue, rather they have a conducting tissue that is more similar to that of bryophytes.
• Originally the plant was interpreted as a tracheophyte, based on the fact that the stem has a simple central vascular cylinder. Interpretation made recently in the light of additional data indicated that Rhynia major had water-conducting tissue that lacks the secondary thickening bars that are normally seen in the xylem of Rhynia gwynne-vaughanii, more like the water-conducting system (hydrome) of moss sporophytes.
• Hence, Edwards in 1986 reinterpreted Rhynia major as a non-vascular plant and renamed it Aglaophyton major. 
• Hence, the correct answer is option 3. 

The correct answer is Option 4 i.e.A ‐ I and V ; B ‐ II, IV, and V

Key Points

• Bryophytes are terrestrial, non-vascular cryptogram that requires water for fertilisation, hence, they are also called amphibian plants. 
• They are advanced plants over the algae (Thallophyta) as they have multicellular jacketed sex organs i.e., antheridia (male) and archegonia (female). 
• They show distinct alternation of generations. 
• The plant body is called gametophyte and may be thallus (e.g., Riccia) or can be differentiated into rhizoids (root-like), cauloid (stem-like) and phylloid (leaves-like). 
• They lack a 'true' vascular system as their vascular system is not differentiated into xylem and phloem. 
• They can have a vegetative, asexual and sexual mode of reproduction.
• Vegetative reproduction is by te means of reproductive bodies like gemmae, tubers or adventitious buds. 
• Asexual reproduction is by the means of non-motile, wind-dispersed spores which are enclosed in a capsule of the sporophyte. The asexual spore germinates to give rise to a gametophyte. 
• Sexual reproduction is by the means of multicellular jacketed sex organs. 
  • Male sex organ produce male gametes that are biflagellate and coiled structures. 
  • Female sex organ produce female gametes called eggs that are non-motile. 
• Fertilization results in a zygote that develops into an embryo which later turns into sporophytes.
• Hence, Gametophyte is the dominant generation. It is autotrophic and independent. while sporophyte is small, parasite or semi-parasite on the gametophyte. 
• Bryophytes are divided into three classes :
  • Hepaticeae (Liverworts)
  • Anthocerotea (Hornworts)
  • Musci (mosses)

Explanation:

• Unicellular rhizoids are found in liverworts while multicellular rhizoids are found in mosses.
• Mosses and hornworts are the earlier known plant form that has stomata and their stomata are located on the sporangium of the sporophyte.
• Pyrenoids are proteins aggregates most exclusively consisting of Ribulose 1,5-bisphosphate carboxylase/oxygenase enzyme amongst other minor proteins. Pyrenoids are generally absent in bryophytes and only found in hornworts. 
• All bryophytes have gametophyte as their dominant generation.

Hence, the correct answer is Option 4.

 Additional Information

1. Liverworts 
   • The plant body is a thallus, dorsoventrally flattened and dichotomously branched. 
   • The dorsal surface is marked by grooves while the ventral surface consists of unicellular rhizoids. 
   • Vegetative reproduction takes place by gemmae.
2. Mosses
   • The plant body is differentiated into rhizoids, cauloid and phylloids.
   • They have multicellular rhizoids. 
   • Reproduction is mainly by sexual and asexual modes, and a few times vegetative reproductions is seen. 

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

Explanation:

1. Sponges (Porifera)

• Sponges have different types of larval stages, but the "amphiblastula" larva is a typical free-swimming stage found in some groups of sponges.

2. Cnidarians

• Many cnidarians (such as jellyfish and corals) have a "planula" larva, which is a free-swimming, flat, ciliated larval form that settles to form the adult polyp.

3. Flatworms (Platyhelminthes)

• Flatworms, particularly parasitic ones like trematodes (flukes), have complex lifecycles with several larval stages, including the "cercariae" stage, which is a free-swimming larva that can infect the next host in the lifecycle.

Conclusion:
Combining the correct matches, the appropriate option that corresponds to all correct matches is:

a. Sponges - ii. Amphiblastula
b. Cnidarians - iii. Planula
c. Flatworms - i. Cercariae

The correct answer is A  - ii, B - iv, C - i, D - iii

Explanation:

1. Phytophthora infestans

• Correct Taxonomic Group: Oomycetes
• Phytophthora infestans is well-known as the organism responsible for potato late blight.
• Despite being similar to true fungi, it belongs to the group Oomycetes, which are water molds and differ from fungi in several structural and functional aspects. Its cell walls contain cellulose rather than chitin.

2. Cladosporium fulvum

• Correct Taxonomic Group: Fungi
• Cladosporium fulvum is a fungal pathogen that causes leaf mold in tomatoes. As a fungus, it belongs to the taxonomic group known as fungi, characterized by their chitinous cell walls and spore-producing capabilities.

3. Ralstonia solanacearum

• Correct Taxonomic Group: Bacteria
• Ralstonia solanacearum is a well-documented bacterial pathogen causing wilt diseases in various plants. It is a gram-negative bacterium, fitting into the taxonomic group bacteria.

4. Heterodera schachtii

• Correct Taxonomic Group: Nematodes
• Heterodera schachtii, commonly known as the sugar beet cyst nematode, is a nematode that infects the roots of sugar beet and other crops. Nematodes are a group of roundworms, making this pathogen fit the taxonomic group nematodes.

Thus, Based on the detailed explanations above, the correct matches are as follows:

A (Phytophthora infestans) → ii (Oomycetes)
B (Cladosporium fulvum) → iv (Fungi)
C (Ralstonia solanacearum) → i (Bacteria)
D (Heterodera schachtii) → iii (Nematodes)
Thus, the correct option with all the right matches is: A-ii, B-iv, C-i, D-iii