- Understand the concept of biodiversity and its significance.
- Explain the different levels of biodiversity: genetic, species, and ecological diversity.
- Describe the distribution of biodiversity across the globe and factors influencing it.
- Identify major threats to biodiversity and their consequences.
- Discuss conservation strategies, including in situ and ex situ methods.
- Evaluate the importance of biodiversity for ecosystem services and human well-being.
- Analyze the role of biodiversity hotspots in conservation efforts.
Biodiversity and Conservation
CBSE Learning Objectives – Key Concepts & Skills You Must Know
CBSE Revision Notes & Quick Summary for Last-Minute Study
Biodiversity and Conservation
1. Introduction to Biodiversity
- Biodiversity refers to the variety of life on Earth, encompassing species diversity, genetic diversity, and ecological diversity.
- Over 1.5 million species have been recorded, but estimates suggest nearly 6 million species may exist.
2. Importance of Biodiversity
- Biodiversity is crucial for ecosystem functioning and provides numerous ecosystem services such as:
- Pollination
- Pest control
- Climate moderation
- Flood control
- Ethical responsibility to conserve biodiversity for future generations.
3. Species Richness
- Species richness is highest in the tropics due to:
- More evolutionary time
- Constant environment
- Higher solar energy leading to greater productivity.
- Example: More than 70% of all recorded species are animals, with insects making up over 70% of animal species.
4. Causes of Species Loss
- Major causes include:
- Habitat loss and fragmentation
- Over-exploitation
- Biological invasions
- Co-extinctions
- Current extinction rates are 100 to 1000 times higher than historical rates.
5. Conservation Strategies
5.1 In Situ Conservation
- Protecting endangered species in their natural habitats.
- Example: India has 14 biosphere reserves, 90 national parks, and over 450 wildlife sanctuaries.
5.2 Ex Situ Conservation
- Protecting species outside their natural habitats.
- Methods include:
- Zoological parks
- Botanical gardens
- Cryopreservation of gametes
- Tissue culture propagation
6. Biodiversity Hotspots
- Areas with high species richness and endemism that require urgent conservation efforts.
- India has three major hotspots:
- Western Ghats and Sri Lanka
- Himalaya
- Indo-Burma
7. Conclusion
- Biodiversity conservation is a collective responsibility of all nations, emphasized by international agreements like the Convention on Biological Diversity.
CBSE Exam Tips, Important Questions & Common Mistakes to Avoid
Common Mistakes and Exam Tips
Common Pitfalls
- Misunderstanding Biodiversity Levels: Students often confuse genetic, species, and ecological diversity. Ensure you can differentiate between these levels.
- Ignoring Human Impact: Many overlook how human activities contribute to biodiversity loss. Be prepared to discuss specific examples.
- Overlooking Conservation Methods: Students may not fully understand the difference between in situ and ex situ conservation. Clarify these concepts with examples.
Tips for Exam Preparation
- Familiarize with Key Terms: Make sure to know definitions like biodiversity, habitat loss, and species-area relationship.
- Understand Major Causes of Extinction: Remember 'The Evil Quartet' (habitat loss, over-exploitation, biological invasions, and co-extinctions) as key causes of biodiversity loss.
- Use Diagrams Effectively: Practice interpreting pie charts and other diagrams that illustrate biodiversity distribution. They often appear in exams.
- Relate Concepts to Real-World Examples: Be ready to discuss current events or case studies related to biodiversity and conservation efforts.
CBSE Quiz & Practice Test – MCQs, True/False Questions with Solutions
Multiple Choice Questions
A.
To promote tourism
B.
To protect regions with high species richness and endemism
C.
To create areas for agricultural development
D.
To facilitate urban expansion
Correct Answer: B
Solution:
Biodiversity hotspots are regions identified for maximum protection due to their high levels of species richness and endemism, as well as accelerated habitat loss.
A.
Habitat loss and fragmentation
B.
Over-exploitation
C.
Natural disasters
D.
Biological invasions
Correct Answer: C
Solution:
The 'Evil Quartet' refers to habitat loss and fragmentation, over-exploitation, biological invasions, and co-extinctions as major causes of species extinction, not natural disasters.
A.
Natural evolutionary processes
B.
Human activities
C.
Increased speciation rates
D.
Global cooling
Correct Answer: B
Solution:
The high extinction rates observed in recent times are primarily due to human activities, which have accelerated the rate of species loss.
A.
Climate change
B.
Habitat loss and fragmentation
C.
Natural disasters
D.
Genetic mutations
Correct Answer: B
Solution:
The 'Evil Quartet' refers to four major causes of species extinction: habitat loss and fragmentation, over-exploitation, invasive species, and co-extinctions. Habitat loss and fragmentation is considered the most significant among these.
A.
Tropical regions have more evolutionary time.
B.
Tropical regions have less solar energy.
C.
Temperate regions have more stable environments.
D.
Temperate regions have higher productivity.
Correct Answer: A
Solution:
Tropical regions exhibit higher species richness because they have had more evolutionary time, provide a relatively constant environment, and receive more solar energy, contributing to greater productivity.
A.
It allows species to evolve without human interference.
B.
It provides a controlled environment for species at high risk of extinction.
C.
It is cheaper than in situ conservation.
D.
It focuses on conserving entire ecosystems.
Correct Answer: B
Solution:
Ex situ conservation is necessary for species at high risk of extinction as it provides a controlled environment where they can be protected and cared for, away from their natural habitat.
A.
They cover less than 2% of the Earth's land area but contain more than 50% of the world's plant species as endemics.
B.
They are regions with low species richness and low endemism.
C.
They are areas where the rate of species extinction is lower than the global average.
D.
They are regions that have been identified for their potential to support large-scale agricultural development.
Correct Answer: A
Solution:
Biodiversity hotspots are regions that cover less than 2% of the Earth's land area but contain a significant proportion of the world's plant species as endemics. They are characterized by high species richness and high degree of endemism.
A.
It indicates the rate of species extinction.
B.
It shows the relationship between species richness and area.
C.
It measures the biodiversity of a single species.
D.
It predicts climate change effects on species.
Correct Answer: B
Solution:
The slope of regression in a species-area relationship indicates how species richness increases with area.
A.
22%
B.
72%
C.
50%
D.
30%
Correct Answer: A
Solution:
The species diversity of plants is much less than that of animals, comprising 22% of the world's recorded species.
A.
Increased pollution
B.
Control of floods and soil erosion
C.
Decreased agricultural productivity
D.
Increased disease spread
Correct Answer: B
Solution:
Among the ecosystem services provided by biodiversity are control of floods and soil erosion.
A.
Botanical gardens
B.
Seed banks
C.
Biosphere reserves
D.
Zoological parks
Correct Answer: C
Solution:
Ex situ conservation involves protecting species outside their natural habitats, such as in botanical gardens, seed banks, and zoological parks. Biosphere reserves are part of in situ conservation.
A.
Habitat loss and fragmentation
B.
Increased genetic diversity
C.
Natural population growth
D.
Stable climate conditions
Correct Answer: A
Solution:
Habitat loss and fragmentation is the most important cause driving animals and plants to extinction.
A.
They have a short lifespan.
B.
They are found only in tropical regions.
C.
They make up more than 70% of all animal species.
D.
They have fewer predators.
Correct Answer: C
Solution:
Insects are the most species-rich taxonomic group because they make up more than 70% of all animal species.
A.
Polar regions
B.
Temperate regions
C.
Tropical regions
D.
Desert regions
Correct Answer: C
Solution:
Species richness is generally highest in the tropics.
A.
They are used for agricultural purposes.
B.
They serve as last refuges for rare and threatened plants.
C.
They are sites for industrial development.
D.
They are used for mining activities.
Correct Answer: B
Solution:
Sacred groves serve as the last refuges for a large number of rare and threatened plants.
A.
Zoological parks
B.
Biosphere reserves
C.
Botanical gardens
D.
Seed banks
Correct Answer: B
Solution:
Biosphere reserves are a method of in situ conservation, not ex situ.
A.
22%
B.
70%
C.
50%
D.
30%
Correct Answer: B
Solution:
Insects make up more than 70% of the total animal species.
A.
22%
B.
50%
C.
70%
D.
90%
Correct Answer: C
Solution:
More than 70% of all the species recorded are animals.
A.
They are regions with high agricultural productivity.
B.
They are areas where biodiversity is legally protected due to cultural significance.
C.
They are regions designated for urban development.
D.
They are areas with low species richness.
Correct Answer: B
Solution:
Sacred groves are areas where biodiversity is protected due to their cultural and religious significance, serving as refuges for rare and threatened species.
A.
It has low species richness but high endemism.
B.
It covers a large geographical area with uniform species distribution.
C.
It has high species richness and a high degree of endemism.
D.
It is primarily composed of non-native species.
Correct Answer: C
Solution:
Biodiversity hotspots are characterized by high species richness and a high degree of endemism, meaning many species are unique to these areas.
A.
More evolutionary time
B.
Less solar energy
C.
Frequent environmental changes
D.
Lower productivity
Correct Answer: A
Solution:
Tropics have had more evolutionary time, providing a relatively constant environment and more solar energy, which contributes to greater productivity.
A.
In situ conservation
B.
Ex situ conservation
C.
Cryopreservation
D.
Tissue culture
Correct Answer: A
Solution:
In situ conservation involves protecting the entire ecosystem, thereby conserving its biodiversity. This method focuses on maintaining species in their natural habitats.
A.
High species richness
B.
Low species richness
C.
Uniform species distribution
D.
Presence of a keystone species
Correct Answer: A
Solution:
David Tilman's long-term ecosystem experiments demonstrated that plots with more species showed less year-to-year variation in total biomass, indicating that high species richness contributes to ecosystem stability.
A.
Habitat loss and fragmentation
B.
Increased rainfall
C.
Decreased solar energy
D.
Stable climate
Correct Answer: A
Solution:
Habitat loss and fragmentation is the most important cause driving animals and plants to extinction.
A.
Over-exploitation
B.
Pollution
C.
Habitat fragmentation
D.
Climate change
Correct Answer: C
Solution:
Habitat loss and fragmentation is the most important cause driving animals and plants to extinction.
A.
They serve as natural laboratories for genetic modification.
B.
They are areas where all human activities are allowed to promote coexistence.
C.
They act as refuges for rare and threatened species.
D.
They are used for large-scale agricultural activities.
Correct Answer: C
Solution:
Sacred groves are protected areas that serve as refuges for rare and threatened species, often due to cultural and religious significance.
A.
Longer evolutionary time
B.
Higher levels of pollution
C.
Greater frequency of natural disasters
D.
Lower solar energy availability
Correct Answer: A
Solution:
Tropical regions have had more evolutionary time, which allows for greater diversification and species richness.
A.
Natural evolutionary processes
B.
Human activities
C.
Increased volcanic activity
D.
Decreased solar radiation
Correct Answer: B
Solution:
The accelerated rates of species extinction are largely due to human activities such as habitat destruction, pollution, and over-exploitation.
A.
It suggests that removing species from an ecosystem has no effect.
B.
It compares species in an ecosystem to rivets in an airplane, where losing too many can lead to ecosystem collapse.
C.
It states that ecosystems are unaffected by the loss of key species.
D.
It proposes that all species in an ecosystem are equally important.
Correct Answer: B
Solution:
The 'rivet popper hypothesis' compares species in an ecosystem to rivets in an airplane, suggesting that losing too many can weaken the ecosystem, potentially leading to collapse.
A.
They are regions with low species richness and high habitat stability.
B.
They are regions with high species richness and high degree of endemism.
C.
They are regions with low species richness and low degree of endemism.
D.
They are regions with high species richness and low habitat stability.
Correct Answer: B
Solution:
Biodiversity hotspots are regions with high levels of species richness and a high degree of endemism, making them critical areas for conservation efforts.
A.
Industrial manufacturing
B.
Pollination by insects
C.
Urban development
D.
Mining activities
Correct Answer: B
Solution:
Pollination by insects is an example of an ecosystem service provided by biodiversity. It is essential for the reproduction of many plants and the production of fruits and seeds.
A.
Species richness
B.
Ecosystem productivity
C.
Resistance to environmental perturbations
D.
Invasive species resistance
Correct Answer: D
Solution:
The introduction of a non-native species that affects the population of a native herbivore suggests a reduction in the ecosystem's resistance to invasions by alien species.
A.
Zoological parks
B.
Botanical gardens
C.
Biosphere reserves
D.
Seed banks
Correct Answer: C
Solution:
In situ conservation involves protecting species in their natural habitat, such as in biosphere reserves.
A.
Biosphere reserves
B.
Sacred groves
C.
Zoological parks
D.
National parks
Correct Answer: C
Solution:
Ex situ conservation involves protecting species outside their natural habitats, such as in zoological parks.
A.
Through abiotic components
B.
By human intervention
C.
Through biotic components
D.
By reducing biodiversity
Correct Answer: C
Solution:
Ecosystems control floods and soil erosion through their biotic components.
A.
Ex situ conservation
B.
In situ conservation
C.
Cryopreservation
D.
Tissue culture propagation
Correct Answer: B
Solution:
In situ conservation involves protecting species in their natural habitats, ensuring the protection of entire ecosystems.
A.
Small rodents
B.
Migratory birds
C.
Insects
D.
Amphibians
Correct Answer: B
Solution:
Migratory birds, which require large territories for nesting and feeding, are more likely to be adversely affected by habitat fragmentation.
A.
Establishing a national park on the island
B.
Creating a seed bank for the plant species
C.
Introducing the plant species to mainland botanical gardens
D.
Implementing a captive breeding program
Correct Answer: B
Solution:
Creating a seed bank is an ex situ conservation strategy that allows for the preservation of plant genetic material, which is crucial for species that are endemic to small areas.
A.
Higher levels of human activity
B.
More evolutionary time and a relatively constant environment
C.
Greater availability of fossil fuels
D.
Higher levels of pollution
Correct Answer: B
Solution:
Tropical regions have high species richness primarily due to more evolutionary time, a relatively constant environment, and higher solar energy input, which contributes to greater productivity.
A.
Ex situ conservation
B.
In situ conservation
C.
Cryopreservation
D.
Tissue culture propagation
Correct Answer: B
Solution:
In situ conservation involves protecting species in their natural habitats, ensuring that the entire ecosystem is preserved. This is contrasted with ex situ conservation, which involves protecting species outside their natural habitats.
A.
Species-area relationship
B.
Rivet popper hypothesis
C.
Biodiversity-stability hypothesis
D.
Competitive exclusion principle
Correct Answer: C
Solution:
The observation supports the biodiversity-stability hypothesis, which suggests that ecosystems with greater species diversity tend to be more stable and show less variability.
A.
Economic benefits
B.
Aesthetic value
C.
Moral responsibility
D.
Scientific research
Correct Answer: C
Solution:
The ethical argument for conserving biodiversity is based on our moral duty to care for all species.
A.
They serve as a natural habitat for endangered species.
B.
They are used for agricultural purposes to enhance food security.
C.
They provide raw materials for pharmaceutical industries.
D.
They are sites for cultural festivals that raise awareness about biodiversity.
Correct Answer: A
Solution:
Sacred groves are areas of forest preserved for religious or cultural reasons, and they often serve as natural habitats for rare and endangered species, thus playing a crucial role in biodiversity conservation.
A.
Habitat loss and fragmentation
B.
Over-exploitation
C.
Climate change
D.
Biological invasions
Correct Answer: C
Solution:
The 'Evil Quartet' refers to habitat loss and fragmentation, over-exploitation, biological invasions, and co-extinctions. Climate change, while a significant threat, is not listed as part of the 'Evil Quartet' in this context.
A.
To increase economic profits
B.
To ensure the survival of the fittest species
C.
To fulfill our moral duty to care for other species
D.
To promote genetic engineering
Correct Answer: C
Solution:
The ethical argument for conserving biodiversity is based on the belief that every species has intrinsic value and that we have a moral duty to care for their well-being and pass on our biological legacy to future generations.
A.
Economic value
B.
Ethical responsibility
C.
Ecosystem services
D.
All of the above
Correct Answer: D
Solution:
Biodiversity conservation is important for economic, ethical, and ecosystem service reasons.
A.
Habitat loss
B.
Over-exploitation
C.
Pollination
D.
Biological invasions
Correct Answer: C
Solution:
Pollination is an ecosystem service, not a cause of biodiversity loss.
A.
Moral responsibility to future generations
B.
Intrinsic value of all species
C.
Provision of ecosystem services like pollination
D.
Aesthetic appreciation of nature
Correct Answer: C
Solution:
Biodiversity provides utilitarian benefits such as ecosystem services, including pollination, which are essential for human survival.
A.
Increased species diversity
B.
Enhanced genetic variation
C.
Population declines in species requiring large territories
D.
Improved ecosystem resilience
Correct Answer: C
Solution:
Habitat fragmentation leads to population declines in species that require large territories and those with migratory habits, as their habitats become fragmented and reduced in size.
A.
Increased biodiversity leads to less year-to-year variation in total biomass.
B.
Decreased biodiversity enhances ecosystem resilience.
C.
Biodiversity has no effect on ecosystem productivity.
D.
Biodiversity reduces resistance to biological invasions.
Correct Answer: A
Solution:
David Tilman's experiments demonstrated that plots with more species showed less year-to-year variation in total biomass, indicating that increased biodiversity contributes to ecosystem stability.
True or False
Correct Answer: True
Solution:
The Amazon rainforest is estimated to produce 20% of the total oxygen in the Earth's atmosphere through photosynthesis.
Correct Answer: True
Solution:
In situ conservation refers to the protection of endangered species in their natural habitat.
Correct Answer: True
Solution:
India is recognized as one of the 12 mega diversity countries of the world.
Correct Answer: True
Solution:
The excerpts state that more than 15,500 species worldwide are facing the threat of extinction.
Correct Answer: False
Solution:
The current species extinction rates are estimated to be 100 to 1,000 times faster than in pre-human times.
Correct Answer: True
Solution:
The tropics provide a relatively constant environment and receive more solar energy, which contributes to greater productivity and species richness.
Correct Answer: False
Solution:
More than 70% of all recorded species are animals, not plants.
Correct Answer: False
Solution:
The current species extinction rates are estimated to be 100 to 1,000 times faster than in pre-human times.
Correct Answer: True
Solution:
The current species extinction rates are largely attributed to human activities.
Correct Answer: False
Solution:
Biodiversity hotspots cover less than 2% of the earth's land area but are regions of high species richness and endemism.
Correct Answer: True
Solution:
Sacred groves are indeed areas set aside for religious or cultural reasons and play a significant role in conserving biodiversity.
Correct Answer: False
Solution:
India has 14 biosphere reserves and 448 wildlife sanctuaries.
Correct Answer: True
Solution:
The current species extinction rates are estimated to be 100 to 1,000 times faster than in pre-human times.
Correct Answer: False
Solution:
The species diversity of animals is higher than that of plants, with animals comprising 72% of species compared to 22% for plants.
Correct Answer: True
Solution:
The current extinction rates have accelerated to be 100 to 1,000 times faster than the rates observed before human influence, largely due to human activities.
Correct Answer: False
Solution:
Biodiversity hotspots cover less than 2% of the Earth's land area.
Correct Answer: True
Solution:
Insects are the most species-rich taxonomic group, making up more than 70% of all animal species.
Correct Answer: False
Solution:
The group Fungi has more species than the combined total of vertebrate species.
Correct Answer: True
Solution:
The Amazon rainforest is called the 'lungs of the planet' due to its vast biodiversity and oxygen production.
Correct Answer: True
Solution:
In Meghalaya, sacred groves serve as the last refuges for a large number of rare and threatened plants.
Correct Answer: True
Solution:
The Amazon rainforest is indeed being cut and cleared for these purposes.
Correct Answer: True
Solution:
The Amazon rainforest is indeed being cut and cleared for cultivating soya beans and for conversion to grasslands for raising beef cattle, as mentioned in the excerpts.
Correct Answer: True
Solution:
According to the excerpts, the number of fungi species exceeds the combined total of fish, amphibians, reptiles, and mammals.
Correct Answer: True
Solution:
Biodiversity hotspots collectively cover less than 2% of the Earth's land area, but they are regions of high species richness and endemism.
Correct Answer: False
Solution:
Sacred groves are found in various regions in India, including Khasi and Jaintia Hills, Aravalli Hills, Western Ghats, and others.
Correct Answer: True
Solution:
The species diversity of plants is 22 per cent, which is much less than that of animals at 72 per cent.
Correct Answer: True
Solution:
India has 448 wildlife sanctuaries.
Correct Answer: True
Solution:
Sacred groves in India, such as those in Meghalaya, serve as refuges for a large number of rare and threatened plant species, playing a crucial role in conservation.
Correct Answer: True
Solution:
In situ conservation efforts focus on protecting species by maintaining their natural ecosystems, ensuring the protection of entire habitats.
Correct Answer: False
Solution:
Ex situ conservation involves protecting species outside their natural habitat.
Correct Answer: False
Solution:
More than 70% of the recorded species are animals, with insects making up the majority of these species, not plants.
Correct Answer: True
Solution:
The species-area relationship, which describes how species richness increases with the area, is typically represented as a rectangular hyperbolic function.