Conservation
Sustainable Resources
Learning Objective 1 & 2: A sustainable resource is one which is produced as rapidly as it is removed from the environment so that it does not run out. This means the rate of consumption equals or is less than the rate of regeneration.
Some resources can be conserved and managed sustainably, specifically forests and fish stocks. If these are managed correctly, they remain available for future generations.
Sustainable Resource
Definition: A resource that is produced (or regenerated) as rapidly as it is removed from the environment, ensuring it does not run out.
Key Criterion: Rate of production \ge Rate of removal.
Sustainable vs. Unsustainable Resources
| Status |
|---|
| Regenerates if managed correctly. |
| Reproduces if population is protected. |
| Formed over millions of years; used in centuries. Will run out. |
⚠︎ Confusing Sustainability with Renewable
Error: Thinking all renewable resources are automatically sustainable.
Correction: A resource is only sustainable if the rate of use does not exceed the rate of regeneration. For example, fish are renewable, but if overfished faster than they breed, they become unsustainable.
Correction: A resource is only sustainable if the rate of use does not exceed the rate of regeneration. For example, fish are renewable, but if overfished faster than they breed, they become unsustainable.
Defining Sustainable Resources
When to use: When asked to define or describe a sustainable resource.
Why examiners accept this: The definition hinges on the rate of production versus removal. You must mention both aspects.
Correct phrasing: "A resource that is produced as rapidly as it is removed from the environment so that it does not run out."
Example Answer: "Fossil fuels are not sustainable because they are used much faster than they are formed."
Why examiners accept this: The definition hinges on the rate of production versus removal. You must mention both aspects.
Correct phrasing: "A resource that is produced as rapidly as it is removed from the environment so that it does not run out."
Example Answer: "Fossil fuels are not sustainable because they are used much faster than they are formed."
Sustainable Resources
Q:
Describe what is meant by a sustainable resource.
A:
A resource which is produced as rapidly as it is removed from the environment so that it does not run out.
Causes of Endangerment and Extinction
Learning Objective 3: Organisms become endangered or extinct due to several human and environmental factors:
- Climate change: Alters habitats faster than species can adapt.
- Habitat destruction: Removal of living areas (e.g., deforestation, urbanization).
- Hunting/Poaching: Direct killing for food, trophies, or trade.
- Overharvesting: Removing organisms faster than they can reproduce.
- Pollution: Contaminants harm health and reduce reproductive success.
- Introduced species: Non-native species compete with or prey on native species.
Endangered Species
Definition: A species that is at serious risk of extinction in the near future due to a decline in population size or habitat loss.
Impact of Introduced Species
When a foreign species is introduced to a new habitat, it may:
- Disrupt food chains by preying on native species.
- Compete for food and space.
- Introduce new diseases to which native species have no immunity.
⚠︎ Vague Causes of Extinction
Error: Stating "pollution" or "climate change" without explanation.
Correction: You must explain how it causes extinction. E.g., "Pollution reduces the quality of water, leading to lower reproduction rates in amphibians."
Correction: You must explain how it causes extinction. E.g., "Pollution reduces the quality of water, leading to lower reproduction rates in amphibians."
Explaining Causes of Extinction
When to use: When asked to explain why a specific species is endangered.
Why examiners accept this: They look for the mechanism of harm, not just the cause.
Correct phrasing: "Habitat destruction removes the food and shelter necessary for survival."
Example Answer: "Climate change alters the temperature, making the environment unsuitable for species that cannot migrate or adapt quickly enough."
Why examiners accept this: They look for the mechanism of harm, not just the cause.
Correct phrasing: "Habitat destruction removes the food and shelter necessary for survival."
Example Answer: "Climate change alters the temperature, making the environment unsuitable for species that cannot migrate or adapt quickly enough."
Causes of Endangerment
Q:
State two reasons why a species might become endangered.
A:
- Habitat destruction. 2. Climate change.
Conservation Methods for Endangered Species
Learning Objective 4: Endangered species can be conserved using:
- Monitoring and protecting species/habitats: Counting populations and securing land from development.
- Education: Raising awareness to reduce human impact (e.g., anti-poaching campaigns).
- Captive breeding programmes: Breeding animals in zoos/sanctuaries to release them later.
- Seed banks: Storing seeds of endangered plants for future planting.
Captive Breeding Programme
Definition: A programme where endangered animals are bred in controlled environments (like zoos) to increase their population size before being released back into the wild.
Why Seed Banks are Effective for Plants
Plants are easily conserved in seed banks because:
- Seeds are small and easy to collect.
- Some plants produce many seeds.
- Seeds can remain dormant with low metabolism, requiring little maintenance.
⚠︎ Confusing Seed Banks with Zoos
Error: Suggesting seed banks are used for animal conservation.
Correction: Seed banks are specifically for plants. For animals, use captive breeding programmes or zoos.
Correction: Seed banks are specifically for plants. For animals, use captive breeding programmes or zoos.
Describing Conservation Methods
When to use: When asked to describe how a species is conserved.
Why examiners accept this: They want specific methods, not general ideas.
Correct phrasing: "Captive breeding programmes increase the population size by breeding individuals in controlled environments."
Example Answer: "Seed banks are used because seeds can be stored for long periods without losing viability."
Why examiners accept this: They want specific methods, not general ideas.
Correct phrasing: "Captive breeding programmes increase the population size by breeding individuals in controlled environments."
Example Answer: "Seed banks are used because seeds can be stored for long periods without losing viability."
Conservation Methods
Q:
Describe three ways in which endangered species can be conserved.
A:
- Monitoring and protecting habitats. 2. Education of the public. 3. Captive breeding programmes.
Conserving Forests (Supplement)
Learning Objective 5: Forests can be conserved using:
- Education: Teaching people about the importance of forests.
- Protected areas: Establishing national parks where logging is banned.
- Quotas: Limiting the number of trees that can be cut down.
- Replanting: Planting new trees to replace those harvested (afforestation/reforestation).
Protected Area
Definition: A designated area of land or water where human activities (like logging or hunting) are restricted to protect the natural environment.
Forest Conservation Strategy
A sustainable forest management plan might involve:
- Setting a quota of 100 trees per hectare.
- Creating a protected area around critical wildlife habitats.
- Replanting two trees for every one cut down.
⚠︎ Missing Replanting in Forest Conservation
Error: Only mentioning protection or quotas.
Correction: You must include replanting to ensure the resource is sustainable.
Correction: You must include replanting to ensure the resource is sustainable.
Explaining Forest Conservation
When to use: When asked to explain how forests are conserved.
Why examiners accept this: They look for the link between the method and sustainability.
Correct phrasing: "Quotas prevent overharvesting, ensuring the forest can regenerate."
Example Answer: "Replanting ensures that the number of trees does not decrease over time."
Why examiners accept this: They look for the link between the method and sustainability.
Correct phrasing: "Quotas prevent overharvesting, ensuring the forest can regenerate."
Example Answer: "Replanting ensures that the number of trees does not decrease over time."
Forest Conservation
Q:
Explain how forests can be conserved using quotas.
A:
Quotas limit the number of trees that can be harvested, ensuring that the rate of removal does not exceed the rate of regrowth.
Conserving Fish Stocks (Supplement)
Learning Objective 6: Fish stocks can be conserved using:
- Education: Raising awareness about overfishing.
- Closed seasons: Banning fishing during breeding periods.
- Protected areas: Marine reserves where fishing is prohibited.
- Controlled net types and mesh size: Allowing small fish to escape.
- Quotas: Limiting the total catch.
- Monitoring: Tracking population sizes.
Mesh Size
Definition: The size of the holes in a fishing net. Larger mesh sizes allow small, young fish to escape, ensuring they can grow and reproduce.
Fish Stock Management
To conserve tuna stocks:
- Implement closed seasons during spawning.
- Use nets with a minimum mesh size to protect juveniles.
- Set quotas based on scientific monitoring of population levels.
⚠︎ Confusing Mesh Size Effects
Error: Saying small mesh sizes are better.
Correction: Large mesh sizes are used to conserve stocks because they allow young fish to escape and grow.
Correction: Large mesh sizes are used to conserve stocks because they allow young fish to escape and grow.
Explaining Fish Stock Conservation
When to use: When asked to explain how fish stocks are managed.
Why examiners accept this: They want the biological reason (breeding/growth).
Correct phrasing: "Closed seasons allow fish to breed without disturbance."
Example Answer: "Larger mesh sizes prevent the capture of juvenile fish, allowing them to reach reproductive age."
Why examiners accept this: They want the biological reason (breeding/growth).
Correct phrasing: "Closed seasons allow fish to breed without disturbance."
Example Answer: "Larger mesh sizes prevent the capture of juvenile fish, allowing them to reach reproductive age."
Fish Stock Conservation
Q:
Explain how controlled net types help conserve fish stocks.
A:
Controlled net types with larger mesh sizes allow small, young fish to escape, ensuring they can grow and reproduce before being caught.
Reasons for Conservation Programmes (Supplement)
Learning Objective 7: Conservation programmes are set up to:
- Maintain or increase biodiversity: Preserve the variety of life.
- Reduce extinction: Prevent species from disappearing forever.
- Protect vulnerable ecosystems: Safeguard fragile habitats.
- Maintain ecosystem functions:
- Nutrient cycling: Decomposers and plants recycle nutrients.
- Resource provision: Ecosystems provide food, drugs, fuel, and genes.
Biodiversity
Definition: The variety of different species in a habitat or ecosystem.
Resource Provision from Ecosystems
- Food: Crops, livestock, fish.
- Drugs: Medicines derived from plants (e.g., aspirin from willow bark) or animals.
- Fuel: Wood, fossil fuels.
- Genes: Genetic material used to breed disease-resistant crops or livestock.
⚠︎ Omitting Specific Resources
Error: Saying "ecosystems provide resources" without listing them.
Correction: You must specify food, drugs, fuel, and genes to get full marks.
Correction: You must specify food, drugs, fuel, and genes to get full marks.
Describing Reasons for Conservation
When to use: When asked why conservation programmes are important.
Why examiners accept this: They look for specific benefits, not just "saving nature."
Correct phrasing: "Conservation maintains ecosystem functions such as nutrient cycling and resource provision."
Example Answer: "Protecting biodiversity ensures a source of future drugs and genes for agriculture."
Why examiners accept this: They look for specific benefits, not just "saving nature."
Correct phrasing: "Conservation maintains ecosystem functions such as nutrient cycling and resource provision."
Example Answer: "Protecting biodiversity ensures a source of future drugs and genes for agriculture."
Reasons for Conservation
Q:
Describe the reasons for conservation programmes, including resource provision.
A:
Conservation maintains biodiversity and reduces extinction. It protects vulnerable ecosystems and maintains ecosystem functions such as nutrient cycling and resource provision, including food, drugs, fuel, and genes.
Artificial Insemination and IVF (Supplement)
Learning Objective 8: These techniques are used in captive breeding programmes:
- Artificial Insemination (AI): Sperm is collected from a male and inserted into the female's reproductive tract.
- In Vitro Fertilisation (IVF): Eggs and sperm are combined outside the body to form embryos, which are then implanted into a surrogate mother.
Artificial Insemination (AI)
Definition: The process of collecting sperm from a male and inserting it into the reproductive tract of a female to achieve pregnancy.
IVF Process Order
- Collect eggs from female.
- Collect sperm from male.
- Combine eggs and sperm in a lab (in vitro).
- Embryo develops.
- Implant embryo into surrogate mother.
⚠︎ Confusing AI and IVF
Error: Saying IVF involves inserting sperm into the female.
Correction: AI inserts sperm. IVF combines eggs and sperm outside the body.
Correction: AI inserts sperm. IVF combines eggs and sperm outside the body.
Describing AI and IVF
When to use: When asked to describe these techniques.
Why examiners accept this: They want the location of fertilization.
Correct phrasing: "In IVF, fertilisation occurs outside the body."
Example Answer: "AI allows males that cannot mate naturally to contribute genetically."
Why examiners accept this: They want the location of fertilization.
Correct phrasing: "In IVF, fertilisation occurs outside the body."
Example Answer: "AI allows males that cannot mate naturally to contribute genetically."
AI and IVF
Q:
Describe the use of in vitro fertilisation (IVF) in captive breeding programmes.
A:
Eggs and sperm are combined outside the body to form embryos, which are then implanted into a surrogate mother.
Risks of Small Population Size (Supplement)
Learning Objective 9: If a population size decreases, it faces risks:
- Reduced genetic variation: Fewer individuals mean fewer alleles in the gene pool.
- Inbreeding: Increased chance of mating between relatives.
- Expression of harmful recessive alleles: Inbreeding increases homozygosity, revealing harmful traits.
- Reduced adaptability: Less genetic diversity means the population is less likely to survive environmental changes.
Genetic Variation
Definition: The variety of different alleles (gene versions) present in a population's gene pool.
Consequence of Inbreeding
If a small population breeds, relatives mate. If both carry a harmful recessive allele (e.g., aa), their offspring are likely to be homozygous recessive (aa) and express the disease.
⚠︎ Ignoring Genetic Variation
Error: Only mentioning inbreeding.
Correction: You must link inbreeding to reduced genetic variation and the expression of harmful recessive alleles.
Correction: You must link inbreeding to reduced genetic variation and the expression of harmful recessive alleles.
Explaining Risks of Small Populations
When to use: When asked about the risks of a decreasing population.
Why examiners accept this: They look for the genetic consequences.
Correct phrasing: "Reduced genetic variation reduces the chance of adaptation."
Example Answer: "Inbreeding increases the frequency of homozygous recessive genotypes, leading to harmful traits."
Why examiners accept this: They look for the genetic consequences.
Correct phrasing: "Reduced genetic variation reduces the chance of adaptation."
Example Answer: "Inbreeding increases the frequency of homozygous recessive genotypes, leading to harmful traits."
Risks of Small Population Size
Q:
Explain the risks to a species if its population size decreases.
A:
- Reduced genetic variation: Fewer individuals mean fewer alleles in the gene pool. 2. Inbreeding: Increased chance of mating between relatives, leading to harmful recessive traits being expressed. 3. Reduced adaptability: Less genetic diversity means the population is less likely to have individuals with traits that allow survival if the environment changes.