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

The correct answer is Option 2,3 and 4

Explanation:

1. The free-living bacterium Wolbachia is a human parasite.

• Incorrect. Wolbachia is an intracellular bacterium that infects a wide range of arthropods (e.g., insects, spiders) and filarial nematodes.
• It is primarily an endosymbiont, and its relationship with its hosts can range from parasitic to mutualistic.
• While some nematodes that are human parasites (like those causing filariasis) harbor Wolbachia, Wolbachia itself is not a free-living bacterium, nor does it directly parasitize humans. It lives inside other organisms.

2. Myxococcus are a group of predatory bacteria.

• Correct. Myxococcus species (e.g., Myxococcus xanthus) are well-known as "social" or "wolf-pack" predatory bacteria.
• They hunt cooperatively, swarming over prey bacteria, lysing them with secreted enzymes, and then absorbing the nutrients.

3. Dictyostelium is a slime mold that aggregates to form social groups.

• Correct. Dictyostelium discoideum is a classic example of a cellular slime mold. Its life cycle involves individual amoeboid cells that, when faced with starvation, aggregate in response to chemical signals (like cAMP) to form a multicellular structure called a pseudoplasmodium or "slug." This slug then differentiates into a fruiting body, demonstrating a fascinating form of social behavior and multicellular development.

4. Actinomycetes in soil are involved in producing earthy odours.

• Correct. Actinomycetes, particularly members of the genus Streptomyces, are abundant in soil. They are famous for producing various secondary metabolites, including geosmin, a volatile organic compound responsible for the characteristic "earthy" smell of soil, especially after rain (petrichor)

The correct answer is Chemoautotroph

Explanation:

Organisms can be classified into nutritional groups based on their energy source and carbon source. These groups are:

• Energy source: Organisms use either light (photo-) or chemical compounds (chemo-) as their energy source.
• Carbon source: Organisms use either inorganic carbon (e.g., CO₂, termed "autotrophs") or organic carbon (e.g., sugars, termed "heterotrophs") as their carbon source.

Chemoautotrophs are organisms that obtain energy by oxidizing inorganic chemical compounds and use CO₂ as their primary carbon source.

• The bacterium uses a chemical source for energy, specifically by oxidizing reduced nitrite (NO2−" id="MathJax-Element-10-Frame" role="presentation" style="position: relative;" tabindex="0">NO−2NO2− $NO_2^-$ ), which makes it a chemo- organism.
• It uses CO₂ as the principal carbon source, which classifies it as an autotroph.
• Thus, the bacterium is a Chemoautotroph.

Other options:

• Photoautotroph: Photoautotrophs use light as their energy source and CO₂ as their carbon source. Examples include plants, algae, and cyanobacteria.
• Photoheterotroph: Photoheterotrophs use light as their energy source but rely on organic compounds for their carbon source. Examples include certain purple and green non-sulfur bacteria.
• Chemoheterotroph: Chemoheterotrophs obtain energy from chemical compounds and use organic compounds as their carbon source. Examples include most animals, fungi, and many bacteria.

The correct answer is P - iii; Q - i; R - ii; S - v

Explanation:

Bacteria are classified based on their ability to thrive in specific environmental niches. These adaptations allow them to survive and perform essential functions in challenging conditions. Psychrophiles, Barophiles, Mesophiles, and Halophiles are bacterial types categorized by their preferred environmental conditions, such as temperature, pressure, salt concentration, and pH.

• P. Psychrophile - iii (Temperature below 15°C): Psychrophiles are bacteria that thrive in extremely cold environments, such as polar regions, glaciers, and deep oceans. Their cellular mechanisms are adapted to function at low temperatures, making them essential for studying cold-adapted biological processes.
• Q. Barophile - i (Pressure greater than 380 atm): Barophiles, also known as piezophiles, are bacteria that thrive under high-pressure conditions, such as deep-sea environments. Their unique adaptations allow them to maintain cellular integrity and enzymatic functions under extreme pressure.
• R. Mesophile - ii (Temperature between 15°C and 45°C): Mesophiles are bacteria that grow best at moderate temperatures. They are commonly found in human and animal bodies, soil, and water. Most pathogenic bacteria fall into this category, as they thrive at body temperature (approximately 37°C).
• S. Halophile - v (Salt concentration greater than 2M): Halophiles are bacteria that thrive in environments with high salt concentrations, such as salt lakes, saline soils, and salt mines. They have specialized mechanisms to prevent dehydration and maintain osmotic balance in such conditions.

The correct answer is Option 1 and Option 3

Explanation:

1. The Namdapha Flying Squirrel (Biswamoyopterus biswasi) is known only from a single specimen collected in the Namdapha National Park in Arunachal Pradesh, India. Due to its extremely limited range and habitat loss, it is considered critically endangered.
2. The Indian Rhinoceros (Rhinoceros unicornis) is primarily found in northeastern India and parts of Nepal. Conservation efforts have helped its population recover from near extinction in the early 20th century, but it remains vulnerable due to habitat loss and poaching.
3. The Nicobar Shrew (Crocidura nicobarica) is found only on the Nicobar Islands in India. Its status as critically endangered reflects the significant threats it faces from habitat destruction, particularly following the 2004 Indian Ocean tsunami, which severely affected the Nicobar Islands.
4. The Clouded Leopard (Neofelis nebulosa) has a distribution that includes northeastern India, the eastern Himalayas, Southeast Asia, and parts of China. Its population is declining due to habitat loss and poaching for its skin and bones. The Clouded Leopard are listed as "Vulnerable."

The correct answer is P−2 ; Q−1 ; R−4 ; S−3.

Explanation:

• Sleeping sickness (P):
  • Sleeping sickness, also known as African trypanosomiasis, is caused by the protozoan parasite Trypanosoma brucei.
  • This disease is transmitted by the bite of tsetse flies, which are found in sub-Saharan Africa.
  • Symptoms include fever, headaches, joint pain, and sleep disturbances, eventually affecting the central nervous system.
• Chagas disease (Q):
  • Chagas disease, or American trypanosomiasis, is caused by the protozoan parasite Trypanosoma cruzi.
  • The disease is primarily transmitted through the feces of triatomine bugs, also known as "kissing bugs."
  • Symptoms include fever, swelling around the bite site, and in chronic cases, heart or digestive system complications.
• Elephantiasis (R):
  • Elephantiasis, also known as lymphatic filariasis, is caused by the parasitic worm Wuchereria bancrofti.
  • It is transmitted through mosquito bites, and the worms block the lymphatic system, causing severe swelling in limbs or other parts of the body.
  • Treatment includes antiparasitic drugs and management of secondary infections.
• Lyme disease (S):
  • Lyme disease is caused by the bacterium Borrelia burgdorferi.
  • It is transmitted to humans through the bite of infected black-legged ticks, also known as deer ticks.
  • Symptoms include fever, fatigue, rash, and joint pain, and if untreated, it can lead to severe neurological or cardiac issues.

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