CIE iGCSE Biology-20.4 Conservation- Study Notes- New Syllabus
CIE iGCSE Biology-20.4 Conservation- Study Notes – New syllabus
CIE iGCSE Biology-20.4 Conservation- Study Notes -CIE iGCSE Biology – per latest Syllabus.
Key Concepts:
Core
- Describe a sustainable resource as one which is produced as rapidly as it is removed from the environment so that it does not run out
- State that some resources can be conserved and managed sustainably, limited to forests and fish stocks
- Explain why organisms become endangered or extinct, including: climate change, habitat destruction, hunting, overharvesting, pollution and introduced species
- Describe how endangered species can be conserved, limited to:
(a) monitoring and protecting species and habitats
(b) education
(c) captive breeding programmes
(d) seed banks
Supplement
- Explain how forests can be conserved using: education, protected areas, quotas and replanting
- Explain how fish stocks can be conserved using: education, closed seasons, protected areas, controlled net types and mesh size, quotas and monitoring
- Describe the reasons for conservation programmes, limited to:
(a) maintaining or increasing biodiversity
(b) reducing extinction
(c) protecting vulnerable ecosystems
(d) maintaining ecosystem functions, limited to nutrient cycling and resource provision, including food, drugs, fuel and genes - Describe the use of artificial insemination (AI) and in vitro fertilisation (IVF) in captive breeding programmes
- Explain the risks to a species if its population size decreases, reducing genetic variation (knowledge of genetic drift is not required)
What Is a Sustainable Resource?
Definition:
A sustainable resource is a natural resource that is produced or replaced as quickly as it is used, so it does not run out over time.
📌 Key Points:
- It can be used continuously without causing long-term damage to the environment.
- It ensures that future generations can also benefit from it.
Examples include:
- Timber from managed forests (where trees are replanted)
- Fish from well-regulated fisheries
- Solar and wind energy (which are naturally renewable)
🧠 In Short: A sustainable resource is one that is renewed at the same rate it is used, making it environmentally friendly and long-lasting.
Sustainable Management of Natural Resources
Key Statement:
Some natural resources, such as forests and fish stocks, can be conserved and managed sustainably to prevent them from running out.
📌 What This Means:
- Using resources at a rate that allows them to renew or recover naturally.
- Protecting ecosystems while still meeting human needs.
🌳 Example: Forests
- Replanting trees after logging (reforestation)
- Selective logging – only some trees are cut down
- Protected areas and laws to limit deforestation
🐟 Example: Fish Stocks
- Fishing quotas – limits on how many fish can be caught
- Breeding season bans – no fishing during key reproductive times
- Selective nets – allow young fish to escape and grow
🧠 Final Thought: Conserving resources like forests and fish stocks ensures they remain available for future generations and helps maintain biodiversity and ecosystem balance.
Why Do Organisms Become Endangered or Extinct?
An endangered species is one that is at serious risk of becoming extinct in the near future. Extinction means that no individuals of the species remain alive anywhere on Earth.
There are several major human-caused and natural factors that can lead to this:
1. Climate Change
Sudden or long-term changes in temperature, rainfall, or sea level can make environments unsuitable for certain species. Many cannot adapt fast enough or migrate elsewhere.
📌 Example: Polar bears are at risk due to melting Arctic ice caused by global warming.
2. Habitat Destruction
Forests, wetlands, coral reefs, and other natural habitats are often cleared for housing, agriculture, or mining. This forces animals out of their homes, especially specialist species.
📌 Example: Orangutans lose their forest habitat due to palm oil plantations.
3. Hunting and Poaching
Excessive hunting for food, sport, or illegal trade (e.g., ivory, skins) causes population decline. If not regulated, it may lead to extinction.
📌 Example: Tigers are endangered due to poaching for their bones and skins.
4. Overharvesting
Taking wild plants or animals faster than they can reproduce (e.g., overfishing, logging) causes population decline and ecosystem imbalance.
📌 Example: Overfishing has caused some fish species to collapse.
5. Pollution
Pollution (chemicals, plastics, oil) affects water, air, and soil. It can poison wildlife, disrupt reproduction, and destroy habitats.
📌 Example: Sea turtles often die after swallowing ocean plastic.
6. Introduced (Invasive) Species
Non-native species brought by humans into new ecosystems may outcompete or prey on local species that have no defense.
📌 Example: In Australia, cane toads and rabbits have harmed native wildlife.
🧠 Final Summary Table:
| Cause | Effect on Species |
|---|---|
| Climate change | Habitat becomes unsuitable, organisms can’t adapt |
| Habitat destruction | Loss of shelter, food, and breeding areas |
| Hunting/Poaching | Sharp population decline due to overexploitation |
| Overharvesting | Species removed faster than they can reproduce |
| Pollution | Poisoning, habitat degradation, reproductive failure |
| Introduced species | Competition, predation, and spread of disease |
Conservation of Endangered Species
Conservation means taking action to protect and preserve species that are at risk of extinction, so their populations can recover and survive into the future.
Ways to Conserve Endangered Species:
(a) Monitoring and Protecting Species and Habitats
- Regularly check population numbers of endangered species
- Create protected areas like wildlife reserves or national parks
- Ban hunting, logging, and pollution in sensitive habitats
📌 This helps ensure animals and plants are safe in their natural environment.
(b) Education
- Teach people, especially local communities, about the importance of biodiversity
- Raise awareness through schools, campaigns, and media
- Encourage responsible behaviour, like not buying products made from endangered species
📌 Education helps people become part of the solution, not the problem.
(c) Captive Breeding Programmes
- Endangered animals are bred in zoos or wildlife centres
- The young are raised safely and may later be released into the wild
- Helps increase population size and maintain genetic diversity
📌 Example: The Arabian oryx and giant panda have been successfully bred this way.
(d) Seed Banks
- Seeds from rare or endangered plants are collected and stored in cold, dry conditions
- This protects plant diversity and allows replanting if a species becomes extinct in the wild
📌 Example: The Svalbard Global Seed Vault stores seeds from around the world as a backup.
🧠 Final Summary Table:
| Method | Purpose |
|---|---|
| Monitoring & protection | Prevent further harm and keep habitats safe |
| Education | Raise awareness and change human behaviour |
| Captive breeding | Increase animal numbers and reintroduce them to the wild |
| Seed banks | Preserve plant species for future generations |
How Forests Can Be Conserved
Forests are essential for biodiversity, climate regulation, and providing resources like oxygen, wood, and medicine. To prevent deforestation and ensure forests survive for future generations, we can use conservation strategies such as:
1. Education
- Teach people about the importance of forests for the environment and human life
- Raise awareness about the effects of deforestation and how to use forest resources responsibly
- Encourage local communities to protect forests and adopt sustainable practices
🧠 Education leads to more responsible choices and better long-term protection.
2. Protected Areas
- Set up national parks, nature reserves, or conservation zones
- Restrict or ban activities like logging, farming, and building in these zones
- Protect habitats, endangered species, and native trees
🦜 Protected areas act as safe zones for forests and wildlife.
3. Quotas
- Set limits on how much timber can be cut or how many trees can be removed
- Implemented by governments or conservation organisations
- Helps prevent overexploitation and allows forests to regrow
🪵 Quotas help balance human needs with nature’s limits.
4. Replanting (Reforestation)
- Plant one or more trees for every tree that is cut down
- Helps restore damaged forests and prevent soil erosion
- Maintains biodiversity, especially by planting native species
🌿 Replanting ensures forests can recover and stay healthy over time.
🧠 Final Summary Table:
| Method | How It Helps Forest Conservation |
|---|---|
| Education | Increases awareness and promotes responsible use |
| Protected areas | Keeps forests safe from harmful human activity |
| Quotas | Limits how many trees can be cut, preventing overuse |
| Replanting | Replaces lost trees and restores forest ecosystems |
How Fish Stocks Can Be Conserved
Overfishing can lead to the collapse of fish populations, affecting food chains and human livelihoods. To prevent this, sustainable fishing methods are used to conserve fish stocks.
1. Education
- Teach fishermen and the public about the importance of conserving fish stocks
- Promote understanding of sustainable fishing practices
- Encourage responsible consumer choices (e.g., choosing sustainably caught fish)
✅ Education helps people make informed decisions and support conservation efforts.
2. Closed Seasons
- Ban or restrict fishing during breeding seasons to allow fish to reproduce
- Helps populations recover naturally without human interference
✅ Closed seasons give fish time to increase in number.
3. Protected Areas
- Designate marine reserves where fishing is limited or banned
- Protects important breeding and nursery areas for fish
✅ Fish populations inside protected areas can grow and spill over into nearby zones.
4. Controlled Net Types and Mesh Size
- Use nets with larger mesh sizes so that young or small fish can escape
- Avoids catching fish that haven’t reproduced yet
- Some nets are designed to reduce by-catch (non-target species)
✅ This helps maintain a healthy breeding population.
5. Quotas
- Governments or fisheries set catch limits (quotas) for specific fish species
- Prevents overfishing by limiting how many fish can be taken
✅ Quotas help ensure fish are not removed faster than they can reproduce.
6. Monitoring
- Use technology like satellites, patrol boats, or tracking systems to check fishing activities
- Ensures fishermen follow the rules (quotas, net size, protected zones)
- Helps collect data to manage fish stocks better
✅ Monitoring keeps fishing practices legal and sustainable.
🧠 Final Summary Table:
| Method | How It Helps Conserve Fish Stocks |
|---|---|
| Education | Encourages responsible fishing and public support |
| Closed seasons | Allows fish to breed and increase population |
| Protected areas | Safeguards breeding grounds and supports population growth |
| Controlled nets/mesh | Protects young fish and reduces wasteful by-catch |
| Quotas | Limits overfishing and ensures sustainable harvest |
| Monitoring | Enforces rules and improves fishery management |
Reasons for Conservation Programmes
Conservation programmes are organised efforts to protect and preserve living organisms and their natural environments. They are important for several key reasons:
(a) Maintaining or Increasing Biodiversity
- Biodiversity refers to the variety of species in an area.
- High biodiversity keeps ecosystems stable, resilient, and productive.
- Conservation protects endangered species and helps restore populations.
📌 A rich variety of plants and animals supports a healthy planet.
(b) Reducing Extinction
- Many species are at risk due to hunting, habitat loss, climate change, and pollution.
- Conservation helps prevent species from becoming permanently extinct.
- It ensures that future generations can benefit from and enjoy diverse wildlife.
📌 Extinction is forever — conservation offers a second chance.
(c) Protecting Vulnerable Ecosystems
- Some ecosystems (like rainforests, coral reefs, and wetlands) are very delicate.
- If damaged, they take a long time to recover, or may never recover at all.
- Conservation keeps these systems intact and functioning.
📌 Protecting whole habitats helps all species that live there.
(d) Maintaining Ecosystem Functions
- 🔁 Nutrient Cycling: Decomposers and plants recycle essential elements like nitrogen and carbon, keeping soil fertile and supporting agriculture.
- 🍽️ Resource Provision: Nature supplies us with:
- Food (e.g., crops, fish, fruits)
- Drugs (e.g., medicines from plants and microbes)
- Fuel (e.g., wood, biofuels)
- Genes (used in breeding for disease resistance or drought tolerance)
📌 Without conservation, we risk losing resources we depend on for survival and innovation.
🧠 Summary Table:
| Reason | Why It Matters |
|---|---|
| Maintain biodiversity | Keeps ecosystems balanced and resilient |
| Reduce extinction | Protects species from disappearing forever |
| Protect vulnerable ecosystems | Preserves habitats like rainforests and coral reefs |
| Maintain ecosystem functions | Supports nutrient cycles and gives us vital resources (food, fuel, medicine, genes) |
Use of AI and IVF in Captive Breeding Programmes
Captive breeding is the process of breeding endangered animals in controlled environments, such as zoos or conservation centres, to help increase their population and prevent extinction.
A. Artificial Insemination (AI)
- Definition: A process where sperm from a male is collected and manually inserted into a female’s reproductive system.
- The male and female do not need to be in the same location.
- Useful for rare or aggressive species, or when animals are spread across different regions.
📌 Helps ensure reproduction even if natural mating is difficult or impossible.
B. In Vitro Fertilisation (IVF)
- Definition: Eggs are removed from a female and fertilised with sperm in a lab dish.
- The resulting embryo is implanted into a uterus (either the same or a surrogate female).
- IVF is more complex and expensive than AI but is effective for species with very low fertility.
📌 Allows better control over genetics and increases the chances of a successful pregnancy.
🧠 Why AI and IVF Are Useful in Conservation:
| Advantage | Explanation |
|---|---|
| Avoids transporting animals | Only sperm/eggs need to be moved, not entire animals |
| Protects genetic diversity | Sperm/eggs can be stored from many individuals |
| Increases success rate | Helps breed animals that won’t or can’t mate naturally |
| Preserves endangered species | Allows more controlled and safe reproduction |
Risks of Reduced Population Size and Genetic Variation
Genetic variation is the difference in genes among individuals in a population. It allows species to adapt to changes in the environment and stay healthy.
⚠️ What Happens When a Population Shrinks?
When a species’ population becomes very small, it faces multiple risks — mainly due to loss of genetic variation.
🔍 Main Risks:
| Risk | Explanation |
|---|---|
| Inbreeding | Fewer individuals means relatives may breed with each other, increasing the risk of genetic defects. |
| Lower disease resistance | With less variation, the species may not have individuals with genes to resist diseases. |
| Poor adaptability | Reduced variation means less chance of surviving environmental changes (e.g., climate change, new predators). |
| Reduced fertility and survival | Some harmful genes can become more common, leading to lower birth rates or weaker individuals. |
| Higher extinction risk | A small, genetically similar population is more likely to go extinct if faced with a new threat. |
🧠 Final Summary:
When a population becomes too small, it loses genetic diversity, making it harder to survive, adapt, and reproduce. This puts the entire species at greater risk of extinction.