6 Most SAQ’s of Ecology and Environment Chapter in Inter 1st Year Zoology (TS/AP)

4 Marks

SAQ-1 : Describe Green house effect.

Introduction

The greenhouse effect is a vital natural process that regulates the Earth’s temperature, making it habitable for life. It is akin to how a greenhouse works, trapping heat to create a warmer environment. Understanding this phenomenon is crucial for comprehending global climate patterns and the impacts of human activities.

How the Greenhouse Effect Works

1. Sunlight Absorption:
   • Solar Radiation: When sunlight reaches the Earth’s atmosphere, a portion of the incoming solar radiation is absorbed by the atmosphere.
2. Radiation Reflection:
   • Albedo Effect: Approximately one-fourth of the solar radiation is reflected back into space by clouds, gases, and the Earth’s surface, known as the albedo effect.
3. Heating of the Earth:
   • Surface Warming: Around half of the incoming solar radiation reaches the Earth’s surface and warms it up, with the Earth absorbing this solar energy.
4. Heat Re-Radiation:
   • Infrared Radiation: The heated Earth’s surface emits infrared radiation (heat) back towards the atmosphere.
5. Greenhouse Gases:
   • Heat Trapping: Gases like carbon dioxide (CO2) and methane (CH4) in the atmosphere trap some of the outgoing infrared radiation.
6. Heat Trapping Mechanism:
   • Atmospheric Blanket: These greenhouse gases act like a blanket, trapping heat within the atmosphere and preventing it from escaping into space, which is crucial for maintaining Earth’s temperature.
7. Balance:
   • Temperature Regulation: This effect creates a balance in the Earth’s temperature, crucial for sustaining life.

Importance and Concerns

1. Vital for Climate: The greenhouse effect is essential for maintaining a stable and habitable climate on Earth.
2. Impact of Human Activities: Increased greenhouse gas emissions from human activities like fossil fuel burning and deforestation have intensified the greenhouse effect, contributing to global warming and climate change.

Summary

The greenhouse effect is a natural mechanism where greenhouse gases in the atmosphere trap heat, keeping the Earth’s surface warm enough to support life. It is a critical process for the Earth’s temperature regulation. However, the enhancement of this effect due to human activities raises significant concerns about global warming and its associated climate changes.

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SAQ-2 : Discuss the causes and effects of global warming. What measures need to be taken to control ‘Global Warming’?

Introduction

Global warming, a significant environmental concern, refers to the ongoing rise in average global temperatures. Understanding its causes and effects is crucial for developing effective strategies to mitigate its impact.

Causes of Global Warming

1. Greenhouse Gas Emissions:
   • Fossil Fuel Burning: The burning of fossil fuels like coal, oil, and natural gas for energy releases carbon dioxide (CO2).
   • Industrial Activities: Manufacturing and other industrial activities contribute to greenhouse gas emissions.
2. Deforestation:
   • Loss of Carbon Sinks: Trees absorb CO2, and deforestation reduces this carbon sink, increasing CO2 levels in the atmosphere.
3. Agriculture:
   • Methane Production: Farming activities, especially livestock farming, produce significant amounts of methane (CH4), a potent greenhouse gas.

Effects of Global Warming

1. Climate Change:
   • Weather Extremes: Increased temperatures lead to more extreme weather events, like hurricanes, droughts, and heavy rainfall.
   • Changing Climate Patterns: Altered climate patterns affect agriculture and ecosystems.
2. Melting Ice Caps and Rising Sea Levels:
   • Polar Ice Melt: Melting of polar ice caps contributes to rising sea levels, threatening coastal regions and small islands.
3. Biodiversity Loss:
   • Habitat Destruction: Changing climates and habitats lead to the loss of species and biodiversity.

Measures to Control Global Warming

1. Reducing Greenhouse Gas Emissions:
   • Renewable Energy Sources: Transition to renewable energy sources like solar, wind, and hydroelectric power.
   • Energy Efficiency: Improve energy efficiency in buildings, transportation, and appliances.
2. Reforestation and Afforestation:
   • Planting Trees: Increase green cover to enhance carbon sequestration.
3. Sustainable Agriculture:
   • Eco-friendly Farming Practices: Adopt sustainable farming practices to reduce methane emissions.
4. Policy and Legislation:
   • Environmental Policies: Implement policies that enforce emission reduction and promote sustainable practices.
5. Public Awareness and Education:
   • Climate Change Education: Educate the public about the causes and effects of global warming and ways to reduce carbon footprints.

Summary

Global warming, primarily caused by greenhouse gas emissions, deforestation, and agriculture, leads to climate change, rising sea levels, and biodiversity loss. To control global warming, it is essential to reduce greenhouse gas emissions, promote reforestation, practice sustainable agriculture, enforce environmental policies, and increase public awareness. These measures are critical for mitigating the impacts of global warming and ensuring a sustainable future.

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SAQ-3 : What are the deleterious effects of depletion of ozone in the stratosphere?

Introduction

Ozone depletion in the stratosphere is a significant environmental concern, particularly affecting the Antarctic region, resulting in the infamous “ozone hole.” This depletion permits harmful ultraviolet (UV) radiation to reach the Earth’s surface, leading to a range of adverse effects on both the environment and human health.

Deleterious Effects of Ozone Depletion

1. Thinning of Ozone Layer: The depletion of ozone in the stratosphere has led to the formation of a large area with a thinned ozone layer, known as the “ozone hole,” particularly over Antarctica.
2. Increased UV Radiation: An intact ozone layer absorbs and filters out much of the harmful UV radiation from the sun. However, due to ozone depletion, an increased amount of UV radiation, especially UV-B, reaches the Earth’s surface.
3. DNA Damage and Mutations: UV-B radiation can cause damage to DNA in living cells, potentially leading to genetic mutations with long-term effects on organisms.
4. Skin Aging and Skin Cancers: Prolonged exposure to UV-B radiation can cause premature skin aging, including wrinkles and pigmentation changes, and increases the risk of various types of skin cancers, such as melanoma, squamous cell carcinoma, and basal cell carcinoma.
5. Eye Problems: UV-B radiation can damage human eyes, causing inflammation of the cornea, known as snow blindness, and can lead to the development of cataracts, a condition that impairs vision and can cause blindness.
6. Impact on Marine Life: UV radiation can penetrate into the ocean and adversely affect marine life, particularly plankton, which is vital for marine ecosystems and the food chain.
7. Crop and Plant Damage: Increased UV radiation can damage crops and interfere with the growth and development of plants, leading to reduced agricultural productivity.
8. Disruption of Ecosystems: The harmful effects of increased UV radiation can disrupt ecosystems, affecting biodiversity and the services ecosystems provide to support life on Earth.

Summary

Ozone depletion in the stratosphere, especially the formation of the ozone hole over Antarctica, leads to harmful effects such as increased UV radiation, DNA damage, skin aging, skin cancers, eye problems, damage to marine life, and disruption of ecosystems. Addressing this issue is crucial by implementing measures to reduce the use of ozone-depleting substances, promoting ozone-friendly technologies, raising public awareness, and conducting research to protect the Earth’s ozone layer. This will ensure a safer and healthier environment for present and future generations.

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SAQ-4 : What is summer stratification? Explain.

Introduction

Summer stratification refers to the layering effect seen in many large lakes and oceans during the warmer months. This phenomenon is caused by temperature differences in water layers, resulting in distinct thermal layers.

Mechanism of Summer Stratification

1. Formation of Layers: In summer, the sun warms the surface water, making it lighter than the cooler, denser water below. This difference in temperature and density creates separate layers.
2. Thermocline: The middle layer, known as the thermocline, acts as a barrier between the warm surface water and the cooler deep water. It is characterized by a rapid change in temperature with depth.

Effects of Summer Stratification

1. Reduced Oxygen Exchange: The thermocline restricts oxygen from the surface from mixing with deeper water, which can lead to low oxygen levels in deeper waters.
2. Impact on Marine Life: This layering can significantly affect marine life, as the distribution of nutrients and oxygen becomes uneven.
3. Changes in Fishing Patterns: Fish and other aquatic organisms may change their habitat according to the temperature and oxygen levels, leading to altered fishing patterns.

Summary

Summer stratification is a significant phenomenon in aquatic environments, characterized by the formation of distinct temperature layers due to solar heating. The key elements are the formation of layers, the presence of a thermocline, and its effects on oxygen exchange and marine life. Understanding this process is crucial for managing marine ecosystems and fishing industries.

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SAQ-5 : Compare the adaptations of animals with freshwater and seawater mode of life.

Introduction

This section explores the adaptations of animals living in freshwater and seawater environments. These adaptations are crucial for their survival and thriving in their respective habitats.

Freshwater Animal Adaptations

1. Osmoregulation: Freshwater animals face the challenge of osmotic water gain. They have adaptations for excreting excess water and conserving salts.
2. Kidney Function: Their kidneys are adapted to excrete dilute urine, helping in the removal of excess water while retaining essential salts.
3. Skin and Scales: The skin and scales of freshwater fish are designed to limit water absorption.

Seawater Animal Adaptations

1. Osmoregulation: In contrast, seawater animals deal with osmotic water loss. They have adaptations for conserving water and excreting excess salts.
2. Kidney Function: Their kidneys are specialized for excreting concentrated urine, which aids in water retention.
3. Salt Glands: Some seawater animals have developed salt glands to actively excrete salt.

Comparison of Adaptations

1. Osmoregulation is a key adaptation in both environments, but freshwater animals focus on excreting excess water, while seawater animals concentrate on retaining water.
2. Kidney Function differs significantly, with freshwater animals producing dilute urine and seawater animals producing concentrated urine.
3. Skin and Scales in freshwater animals are adapted to minimize water intake, while Salt Glands in seawater animals help in salt excretion.

Summary

Adaptations in aquatic animals are essential for maintaining osmotic balance in their respective environments. The primary contrasts between freshwater and seawater animals lie in their strategies for water and salt balance, specifically through osmoregulation, kidney function, and additional adaptations like skin, scales, and salt glands. Understanding these adaptations provides insights into the complexity of life in aquatic ecosystems.

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SAQ-6 : Write a note on DFC. Give the significance in a terrestrial ecosystem.

Introduction

The Detritus Food Chain (DFC) is a significant component of ecological systems, particularly in terrestrial ecosystems. It involves the breakdown of organic matter and dead material, contributing to nutrient cycling and energy flow.

Components of the Detritus Food Chain

1. Detritus: Consists of dead plant and animal matter, fecal matter, and other organic debris.
2. Decomposers: Microorganisms like bacteria and fungi play a crucial role in breaking down detritus.
3. Detritivores: Organisms such as earthworms and certain insects, which feed on detritus, further aiding in decomposition.

Significance of DFC in Terrestrial Ecosystems

1. Nutrient Recycling: DFC is essential for recycling nutrients back into the soil, ensuring soil fertility and supporting plant growth.
2. Energy Flow: It contributes to the flow of energy in an ecosystem, as decomposers and detritivores release energy stored in organic matter.
3. Soil Formation: The process of decomposition aids in soil formation and maintenance of soil structure.
4. Ecosystem Stability: DFC supports the overall stability and health of terrestrial ecosystems by maintaining ecological balance.

Summary

The Detritus Food Chain is a fundamental aspect of terrestrial ecosystems. Its importance lies in nutrient recycling, energy flow, soil formation, and contributing to the overall ecosystem stability. Understanding DFC helps in appreciating the complex interactions and processes that sustain life on land.