Which domain of life is characterized by organisms that often inhabit extreme environments and have cell membranes with ether-linked lipids?
(a) Bacteria
(b) Archaea
(c) Eukarya
(d) Protista

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2. What is a key difference between the domains Bacteria and Archaea?
(a) Bacteria have membrane-bound organelles, while Archaea do not.
(b) Bacterial cell walls have peptidoglycan, while Archaeal cell walls do not have it.
(c) Archaea are only found in extreme environments, while Bacteria are not.
(d) Bacteria are all unicellular, while Archaea include multicellular organisms.

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3. Which of the following kingdoms includes organisms that are mostly unicellular, eukaryotic, and can be autotrophic or heterotrophic?
(a) Fungi
(b) Animalia
(c) Plantae
(d) Protoctista

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4. In which kingdom are organisms predominantly multicellular, autotrophic, and have cell walls made of cellulose?
(a) Animalia
(b) Fungi
(c) Plantae
(d) Protoctista

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5. Which of the following criteria is commonly used to classify viruses?
(a) Their ability to cause specific diseases
(b) The type of nucleic acid they contain
(c) The colour of the virus particles
(d) Their mode of transmission

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6. Which virus group includes viruses such as Coronaviruses and influenza viruses?
(a) Double-stranded DNA viruses
(b) Single-stranded DNA viruses
(c) Double-stranded RNA viruses
(d) Single-stranded RNA viruses

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7. At which level of biodiversity assessment do we evaluate the variety of different species within a particular habitat or ecosystem?
(a) Genetic diversity
(b) Ecosystem diversity
(c) Species diversity
(d) Functional diversity

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8. Which method is best suited for assessing the distribution of species across a gradient of environmental conditions within a single geographical area?
(a) Quadrat Sampling
(b) Point Counts
(c) Transect Sampling
(d) Remote Sensing

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9. Which of the following statements is true regarding the concept of a species?
(a) A species is always defined by its physical characteristics alone.
(b) Different species can interbreed and produce fertile offspring.
(c) Members of the same species are reproductively isolated from members of other species.
(d) The concept of a species can be defined solely based on genetic similarity.

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10. What type of speciation occurs when populations are geographically separated by a physical barrier?
(a) Sympatric Speciation
(b) Parapatric Speciation
(c) Allopatric Speciation
(d) Peripatric Speciation

SECTION 2: SHORT QUESTIONS

1. What are the three domains of life and how do they differ in terms of cellular structure?
The three domains of life are Bacteria, Archaea, and Eukarya. Bacteria and Archaea are prokaryotic, meaning they have no nucleus. Eukarya are eukaryotic and have a nucleus and membrane-bound organelles. Archaea have unique cell membranes, different from bacteria.

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2. Describe one key feature that differentiates Archaea from Bacteria.
Archaea have unique lipids in their cell membranes and their RNA polymerase is more like eukaryotes. Also, Archaea often live in extreme environments, unlike most Bacteria.

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3. Which kingdom is characterized by organisms with chitin in their cell walls and that are mostly decomposers?
The Fungi kingdom has organisms with chitin in their cell walls. They are mostly decomposers, breaking down dead organic matter.

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4. What type of speciation occurs when populations are geographically separated?
This is called allopatric speciation. It happens when a population is divided by a physical barrier like a mountain or river, leading to the formation of new species.

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5. What is the role of genetic drift in the process of speciation?
Genetic drift is a random change in gene frequencies, especially in small populations. It can lead to genetic differences between groups, which may cause speciation over time.

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6. What is the primary method used to assess species distribution along an environmental gradient?
The method is called transect sampling. A line is laid out across a gradient (like a slope), and species are recorded along it to see how distribution changes.

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7. Which level of biodiversity assessment involves evaluating the variety of ecosystems in a region?
This is called ecosystem diversity. It looks at the different ecosystems (like forests, deserts, wetlands) present in a particular region.

SECTION 3: LONG QUESTIONS

Compare and contrast the domains Archaea and Bacteria and discuss how these differences reflect their evolutionary histories.
Both Archaea and Bacteria are prokaryotic, meaning they lack a nucleus. However, Archaea have ether-linked lipids in their membranes and no peptidoglycan in their cell walls, while Bacteria have ester-linked lipids and peptidoglycan. Archaea are more closely related to Eukarya in some genetic features, which shows they have a different evolutionary path from Bacteria, possibly evolving from different ancient ancestors.

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2. Explain the concept of a species according to the biological species concept. How does this definition help in understanding species boundaries and the process of speciation? Provide examples to illustrate your points.
The biological species concept defines a species as a group of organisms that can interbreed and produce fertile offspring. It helps to understand species boundaries by focusing on reproductive isolation. For example, horses and donkeys can mate but produce a sterile mule, so they are different species. This concept also explains how new species form when reproductive barriers develop.

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3. Discuss the mechanisms of allopatric and sympatric speciation.
Allopatric speciation occurs when populations are geographically separated by barriers like mountains or rivers, leading to different evolutionary paths.
Sympatric speciation happens without physical separation, often due to genetic changes, behavior, or niche differences. For example, in lakes, some fish may choose different depths and evolve separately. Both lead to the formation of new species.

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4. Describe the main characteristics of the kingdoms Protoctista, Fungi, Plantae, and Animalia. Provide examples for each kingdom.

• Protoctista: Mostly unicellular, eukaryotic, autotrophic or heterotrophic. Example: Amoeba, Algae

• Fungi: Multicellular (except yeast), cell walls with chitin, decomposers. Example: Mushroom

• Plantae: Multicellular, autotrophic, cell walls with cellulose. Example: Rose plant

• Animalia: Multicellular, heterotrophic, no cell walls, mobile. Example: Human, Lion

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5. Outline the major classification systems for viruses based on their structural features and replication methods. Discuss the significance of these classifications in virology.
Viruses are classified by:

• Type of nucleic acid (DNA or RNA, single or double-stranded)

• Shape (helical, icosahedral, complex)

• Envelope presence (enveloped or non-enveloped)

• Replication method (how they reproduce in host cells)

These classifications help scientists understand how viruses spread, how to develop vaccines, and how to control diseases.

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6. Explain the different levels at which biodiversity can be assessed. How do these levels contribute to our understanding of biological diversity and conservation efforts?
Biodiversity is assessed at three levels:

• Genetic diversity: Variation in genes within a species

• Species diversity: Variety of species in a region

• Ecosystem diversity: Different ecosystems in an area

Each level helps us understand how life is connected and supports conservation planning, like protecting habitats and endangered species.

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7. Discuss the importance of random sampling methods in ecological studies.
Random sampling avoids bias and gives a fair estimate of species population and distribution. It helps ecologists study biodiversity, habitat health, and environmental changes. Methods like quadrats and transects ensure that results are accurate and reliable.

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8. Describe the concept of an ecosystem and niche.
An ecosystem is a community of living organisms and their non-living environment, interacting together (e.g., forest, pond). A niche is the role or function of an organism in an ecosystem, like what it eats, where it lives, and how it interacts with others. Both concepts help understand ecological balance.

INQUISITIVE QUESTIONS

How are viruses classified based on their nucleic acid content and replication method?
Viruses are classified by:

• The type of nucleic acid they contain: DNA or RNA, and whether it’s single-stranded (ss) or double-stranded (ds).

• Their replication method: how they use the host cell to reproduce (e.g., some viruses make DNA from RNA using reverse transcriptase).

This classification helps scientists understand how viruses infect cells and how to create treatments or vaccines.

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2. What may be the drawback in the definition of species according to the biological species concept?
The biological species concept is based on reproductive isolation, meaning species can only breed with their own kind. But there are limitations:

• It doesn’t apply to asexual organisms like bacteria.

• It can’t be used for fossils (we can’t test if they could interbreed).

• Sometimes closely related species can interbreed and produce hybrids (like mule), causing confusion.

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3. How does biodiversity help maintain balance in an ecosystem?
Biodiversity means having many different species in an ecosystem. This helps in:

• Maintaining food chains and natural cycles (like water and carbon).

• Providing stability during changes (like disease or climate shifts).

• Ensuring ecosystem services like clean air, water, and soil fertility.

More diversity means more balance and resilience in the ecosystem.