Interesting Notes 10th Class: Biotechnology – Chapter 17

Interesting Notes 10th Class: Biotechnology – Chapter 17

Biotechnology – Chapter 17


  1. Explain what you mean by the pyramids of number and biomass.
  2. Write a note on the Carbon cycle.
  3. What are the different stages of the Nitrogen cycle?
  4. Write notes on competition, predation, and symbiosis.
  5. Explain how human activities have contributed to the loss of balance in nature.
  6. Write a note on the causes and effects of the air and water pollution.

1. Pyramids of Number and Biomass

Pyramid of Numbers:

  • This pyramid illustrates the count of individual organisms at each trophic level in an ecosystem.
  • Structure:
    • Base: The widest part, representing primary producers (e.g., plants).
    • Next Levels: Herbivores (primary consumers), followed by various levels of carnivores (secondary, tertiary consumers).
    • Trend: Typically, the number of organisms decreases as you move up the pyramid.
  • Example:
    • A grassland ecosystem might have thousands of grass plants (producers), hundreds of grasshoppers (herbivores), dozens of birds (carnivores), and a few hawks (top predators).

Pyramid of Biomass:

  • This pyramid shows the total mass (biomass) of living material at each trophic level.
  • Structure:
    • Base: The primary producers, with the highest biomass.
    • Next Levels: Primary consumers (herbivores), then secondary and tertiary consumers.
    • Trend: Biomass generally decreases from the bottom to the top.
  • Example:
    • In a forest ecosystem, trees (producers) have a large biomass, deer (herbivores) have less, and wolves (carnivores) have even less.
  • Note: In some aquatic systems, this pyramid can be inverted. For example, the biomass of zooplankton (consumers) can exceed that of phytoplankton (producers) due to high turnover rates.

2. Carbon Cycle

The carbon cycle describes the movement of carbon among the atmosphere, biosphere, oceans, and geosphere. Key processes include:

  • Photosynthesis: Plants absorb CO2 from the atmosphere and convert it into glucose and oxygen using sunlight. This process stores carbon in plant biomass.
  • Respiration: Animals and plants break down glucose for energy, releasing CO2 back into the atmosphere.
  • Decomposition: Decomposers (bacteria, fungi) break down dead organisms, returning carbon to the soil and atmosphere.
  • Combustion: The burning of fossil fuels and biomass releases stored carbon into the atmosphere as CO2.
  • Ocean Uptake: Oceans absorb CO2 from the atmosphere. Some of it is used by marine organisms for photosynthesis, and some is stored in ocean sediments.
  • Fossilization: Over millions of years, dead plants and animals can become fossil fuels, storing carbon underground until it is released by human activity.

3. Stages of the Nitrogen Cycle

The nitrogen cycle is the process by which nitrogen is converted into multiple chemical forms as it circulates among the atmosphere, terrestrials, and marine ecosystems. Key stages include:

  • Nitrogen Fixation: Conversion of atmospheric nitrogen (N2) into ammonia (NH3) or related compounds, usually by bacteria in soil or legume root nodules.
  • Nitrification: Conversion of ammonia to nitrites (NO2-) and then to nitrates (NO3-) by nitrifying bacteria.
  • Assimilation: Plants absorb nitrates from the soil and incorporate them into plant proteins and nucleic acids.
  • Ammonification: Decomposition of organic nitrogen (from dead plants and animals) back into ammonia by decomposers.
  • Denitrification: Conversion of nitrates back into atmospheric nitrogen (N2) by denitrifying bacteria, completing the cycle.

4. Notes on Competition, Predation, and Symbiosis


  • Occurs when organisms vie for the same resource (e.g., food, space) in an ecosystem.
  • Types:
    • Intraspecific: Competition within the same species.
    • Interspecific: Competition between different species.
  • Impact: Can limit population growth and influence the distribution and abundance of species.


  • Interaction where one organism (predator) hunts and eats another organism (prey).
  • Impact: Regulates prey populations, influences natural selection (prey evolve defenses), and helps maintain ecological balance.


  • Close and long-term biological interaction between two different biological organisms.
  • Types:
    • Mutualism: Both species benefit (e.g., bees and flowering plants).
    • Commensalism: One species benefits, and the other is neither helped nor harmed (e.g., barnacles on whales).
    • Parasitism: One species benefits at the expense of the other (e.g., ticks on mammals).

5. Human Activities and Loss of Balance in Nature

Human activities have significantly disrupted the natural balance in ecosystems through:

  • Deforestation: This leads to habitat loss, reduced biodiversity, and increased CO2 levels.
  • Pollution: Air, water, and soil pollution harm organisms and disrupt ecological processes.
  • Climate Change: The emission of greenhouse gases alters climate patterns, affecting habitats and species distributions.
  • Overexploitation: Overfishing, hunting, and resource extraction deplete populations faster than they can recover.
  • Urbanization: Expands human settlements at the expense of natural habitats, fragmenting ecosystems.

6. Causes and Effects of Air and Water Pollution

Air Pollution:


  • Emissions from vehicles, industrial processes, and power plants.
  • Burning of fossil fuels and biomass.
  • Release of chemicals and particulate matter into the atmosphere.


  • Respiratory and cardiovascular diseases in humans.
  • Acid rain, which damages ecosystems and buildings.
  • Climate change is due to increased greenhouse gases.
  • Damage to crops and reduced agricultural productivity.

Water Pollution:


  • Discharge of industrial and sewage waste into water bodies.
  • Agricultural runoff containing pesticides and fertilizers.
  • Oil spills and marine dumping.


  • Contamination of drinking water sources leads to health issues.
  • Death of aquatic life due to toxins and reduced oxygen levels (eutrophication).
  • Disruption of aquatic ecosystems and food chains.
  • Economic impacts on fisheries and tourism industries.

Understanding these concepts is crucial for comprehending how ecosystems function and the importance of maintaining ecological balance for the health of the planet.


1. What are the different levels of ecological organization?

The different levels of ecological organization, from smallest to largest, are:

  • Organism: An individual living being (e.g., a single animal, plant, or microbe).
  • Population: A group of organisms of the same species living in a specific area.
  • Community: All the populations of different species living and interacting in an area.
  • Ecosystem: A community of living organisms (biotic factors) interacting with their physical environment (abiotic factors) in a particular area.
  • Biome: A large geographic area with similar climate, flora, and fauna (e.g., deserts, forests).
  • Biosphere: The global sum of all ecosystems, encompassing all life on Earth and the environments in which they live.

2. Define the ecosystem and its components.

Ecosystem: An ecosystem is a system comprising all living organisms (biotic factors) in a particular area, along with the non-living (abiotic) components of their environment, interacting as a system.


  • Biotic Factors: All living things in the ecosystem, such as plants, animals, bacteria, fungi, and any other organisms.
  • Abiotic Factors: Non-living physical and chemical elements in the ecosystem, such as sunlight, air, water, minerals, and temperature.

3. How is the flow of energy different from that of materials?

Flow of Energy:

  • Energy flows through an ecosystem in a one-way stream, from primary producers to various consumers.
  • Unidirectional: Energy enters the ecosystem through photosynthesis (solar energy converted to chemical energy) and moves through trophic levels (food chain) as organisms consume one another.
  • Loss: At each trophic level, a significant amount of energy is lost as heat due to metabolic processes, and thus energy flow is not cyclical.

Flow of Materials (Nutrients):

  • Materials such as carbon, nitrogen, and water cycle within the ecosystem.
  • Cyclical: Nutrients are recycled through biogeochemical cycles (e.g., carbon cycle, nitrogen cycle), moving from the abiotic environment into living organisms and back again.
  • Reuse: These materials are continuously reused within the ecosystem, allowing for the sustainability of life.

4. Define the food chain and food web.

Food Chain: A food chain is a linear sequence of organisms through which nutrients and energy pass as one organism eats another. Each step in the chain represents a different trophic level, starting with primary producers and moving up to primary consumers (herbivores), secondary consumers (carnivores), and so on.

Example: Grass → Grasshopper → Frog → Snake → Hawk

Food Web: A food web is a complex network of interconnected food chains in an ecosystem. It shows the multiple pathways through which energy and nutrients flow, illustrating how different food chains are linked together.

Example: A single plant might be eaten by both insects and mammals, and those insects and mammals might be eaten by multiple predators, creating a web of interactions.

5. What do you mean by the concept of 3Rs concerning the conservation of natural resources?

3Rs: Reduce, Reuse, Recycle


  • Meaning: Minimize the amount of waste we generate.
  • Example: Using less plastic by opting for reusable bags and containers.


  • Meaning: Use items more than once before discarding or recycling them.
  • Example: Reusing glass jars for storage instead of throwing them away.


  • Meaning: Process used materials into new products to prevent waste of potentially useful materials.
  • Example: Recycling paper, plastic, glass, and metals to make new products, thereby conserving raw materials and reducing pollution.


  • Conservation: Helps conserve natural resources by reducing the need for new raw materials.
  • Energy Savings: Saves energy that would otherwise be used to produce new products from raw materials.
  • Environmental Protection: Reduces pollution and greenhouse gas emissions, protecting ecosystems and human health.

By practicing the 3Rs, individuals and communities can significantly contribute to environmental sustainability and the conservation of natural resources.

Long Questions


1. State how your city or village is an ecosystem and describe your position and role in that ecosystem.


  • Ecosystem: Your city or village functions as an ecosystem because it includes all living organisms (people, animals, plants) interacting with their physical environment (buildings, roads, climate, water sources).
  • Components: Just like a natural ecosystem, your city or village has biotic (living) and abiotic (non-living) components that interact with each other.

Your Position and Role:

  • Position: You are an individual within this urban or rural ecosystem.
  • Role:
    • Consumer: You consume resources such as food, water, and energy for your daily needs.
    • Contributor: Through your work, education, and social interactions, you contribute to the economy and community life.
    • Steward: By practicing recycling, conserving water, and participating in community clean-ups, you help maintain the environmental health of your ecosystem.

2. Describe the possible consequences of competition (due to limited resources and overpopulation) in human society.


  • Competition: In human society, competition occurs when the demand for resources (like food, water, housing, and jobs) exceeds the supply due to overpopulation or limited availability.

Possible Consequences:

  • Resource Scarcity: Shortages of essential resources can lead to higher prices and reduced availability.
  • Economic Inequality: Wealth disparities can increase as resources become more limited, with the rich often having better access than the poor.
  • Environmental Degradation: Overuse of resources can result in deforestation, pollution, and loss of biodiversity as people exploit natural resources to meet their needs.
  • Social Tension: Competition for scarce resources can lead to conflicts, increased crime rates, and political instability.
  • Health Issues: Overcrowding and inadequate resources can result in poor living conditions, spreading diseases and decreasing overall public health.

3. Use data from internet and literature search on Pakistan population growth from 1990 to 2000 and interpret this population growth and the possible consequences on our society.


  • Data Search: Use reliable sources such as the World Bank, UN data, or national statistics to find population growth data for Pakistan from 1990 to 2000.

Interpretation and Consequences:

  • Growth Data: From 1990 to 2000, Pakistan’s population increased significantly from approximately 107 million to around 144 million.
  • Possible Consequences:
    • Increased Demand: Higher population puts pressure on food, water, healthcare, and education systems.
    • Urbanization: Rapid population growth often leads to urban sprawl, resulting in overcrowded cities with inadequate infrastructure.
    • Environmental Impact: More people lead to greater deforestation, pollution, and water scarcity due to increased consumption and waste.
    • Economic Pressure: More people means higher competition for jobs, potentially leading to higher unemployment and underemployment rates.

4. Identify environmental problems in your community. What are the causes and what should be done to solve these problems?


  • Identify Problems:
    • Air Pollution: Caused by vehicle emissions, industrial activities, and open burning of waste.
    • Water Pollution: Due to industrial discharge, sewage leaks, and agricultural runoff.
    • Waste Management: Inefficient garbage collection and improper disposal practices.
    • Deforestation: Trees cut down for development or fuel.
    • Loss of Biodiversity: Habitat destruction leading to the decline of local wildlife.

Causes and Solutions:

  • Causes:
    • Rapid urbanization, lack of strict regulations, overpopulation, and unsustainable practices.
  • Solutions:
    • Regulation and Enforcement: Implement and enforce environmental laws and regulations.
    • Public Awareness: Educate the community about the importance of environmental conservation.
    • Sustainable Practices: Promote recycling, water conservation, and the use of renewable resources.
    • Community Action: Organize community clean-up drives and tree-planting initiatives.
    • Infrastructure Improvement: Develop efficient waste management systems and pollution control measures.

5. Actively participate in the community efforts for the conservation of nature.


  • Steps to Participate:
    • Join Local Groups: Become a member of environmental organizations or local community groups focused on conservation.
    • Volunteer: Participate in community clean-ups, tree-planting drives, and other conservation projects.
    • Educate Others: Spread awareness about the importance of conserving nature through talks, social media, and community meetings.
    • Advocate: Support policies and initiatives that aim to protect the environment by attending public meetings, signing petitions, and contacting local representatives.

6. Organize a poster or picture exhibition at school on some environmental topic.


  • Steps to Organize an Exhibition:
    • Choose a Topic: Select an environmental issue such as pollution, climate change, deforestation, or conservation.
    • Plan the Event:
      • Date and Venue: Decide when and where to hold the exhibition.
      • Participants: Involve students, teachers, and local environmental groups.
      • Materials: Gather posters, pictures, and information related to the topic.
    • Create Posters:
      • Content: Include facts, figures, and messages about the chosen topic.
      • Design: Make the posters visually appealing and easy to understand.
    • Promote the Event:
      • Announcements: Use school bulletins, social media, and flyers to inform about the event.
      • Engagement: Encourage students to invite their families and friends.
    • Set Up the Exhibition:
      • Display: Arrange posters and pictures in an organized and attractive manner.
      • Guides: Have students or volunteers available to explain the displays and answer questions.
    • Evaluate and Reflect:
      • Feedback: Collect feedback from visitors to understand the impact.
      • Discussion: Hold a follow-up session to discuss what was learned and how to apply it in real life.

By following these steps, you can raise awareness about environmental issues and encourage your community to take action for conservation.

References and notes

  1.  “Biotechnology”IUPAC Goldbook. 2014. doi:10.1351/goldbook.B00666Archived from the original on January 20, 2022. Retrieved February 14, 2022.
  2.  Ereky, Karl. (June 8, 1919). Biotechnologie der Fleisch-, Fett-, und Milcherzeugung im landwirtschaftlichen Grossbetriebe: für naturwissenschaftlich gebildete Landwirte verfasst. P. Parey. Archived from the original on March 5, 2016. Retrieved March 16, 2022 – via Hathi Trust.
  3.  “Genetic Engineering”. National Human Genome Research Institute, US National Institutes of Health. December 15, 2023. Retrieved December 18, 2023.
  4.  Gupta, Varsha; Sengupta, Manjistha; Prakash, Jaya; Tripathy, Baishnab Charan (October 23, 2016). “An Introduction to Biotechnology”. Basic and Applied Aspects of Biotechnology. pp. 1–21. doi:10.1007/978-981-10-0875-7_1ISBN 978-981-10-0873-3PMC 7119977.
  5.  O’Mathúna, Dónal P. (April 1, 2007). “Bioethics and biotechnology”Cytotechnology53 (1–3): 113–119. doi:10.1007/s10616-007-9053-8ISSN 0920-9069PMC 2267612PMID 19003197.

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