1. Overview
Conservation is the process of looking after the natural environment and resources to ensure they remain available for future generations. As human populations grow, the demand for resources increases, making it vital to manage biodiversity and prevent the extinction of species caused by human activity.
Key Definitions
- Sustainable Resource: A resource which is produced as rapidly as it is removed from the environment so that it does not run out.
- Endangered Species: A species that is at risk of becoming extinct because its population size is very low.
- Extinct: When there are no living individuals of a species left in the world.
- Sustainable Development: Development that meets the needs of the present without compromising the ability of future generations to meet their own needs.
- Biodiversity: The number of different species living in a specific area.
Core Content
Sustainable Resources
Resources can be classified as sustainable if we manage their harvest.
- Forests: Can be managed by only cutting down a certain number of trees and ensuring new ones are planted to replace them.
- Fish Stocks: Can be managed by limiting the number of fish caught so that the remaining population is large enough to reproduce and maintain the population.
Reasons for Species Becoming Endangered or Extinct
Species rarely go extinct for one single reason; usually, it is a combination of:
- Climate Change: Altering habitats (e.g., melting ice caps) faster than species can adapt.
- Habitat Destruction: Cutting down forests or draining wetlands for agriculture or housing.
- Hunting: Killing animals for food, "trophies," or traditional medicine.
- Overharvesting: Taking individuals from the wild faster than they can replace themselves (common in fishing).
- Pollution: Chemicals like pesticides or untreated sewage damaging ecosystems.
- Introduced Species: Non-native species may outcompete, prey upon, or bring new diseases to native species.
How Endangered Species are Conserved
- Monitoring and Protecting: Scientists track population numbers. Habitats are turned into National Parks or Nature Reserves.
- Education: Teaching local people and the public why a species is important and how to protect it.
- Captive Breeding Programmes: Animals are bred in zoos or wildlife centers to increase their numbers before being released back into the wild.
- Seed Banks: Storing seeds in controlled, dry, cold conditions to ensure plants can be grown again if they become extinct in the wild.
Extended Content (Extended Curriculum Only)
Conserving Forests
Forests are vital "carbon sinks" and biodiversity hotspots. They are conserved through:
- Education: Teaching the value of ecosystems.
- Protected Areas: Making it illegal to log in certain zones.
- Quotas: Limiting the volume of timber that can be legally harvested.
- Replanting: Ensuring that for every tree cut down, at least one (preferably of the same species) is planted.
Conserving Fish Stocks
To prevent "overfishing," international laws and local regulations use:
- Education: Helping fishermen understand that overfishing destroys their future livelihood.
- Closed Seasons: Banning fishing during the breeding season so fish can reproduce undisturbed.
- Protected Areas: "No-take" zones where fishing is completely banned to allow populations to recover.
- Controlled Net Types/Mesh Size: Using larger mesh sizes so that young, juvenile fish can swim through and grow to breeding age.
- Quotas: Strict limits on the weight of specific fish species that a boat can bring to shore.
- Monitoring: Using satellite tracking and inspectors to ensure rules are followed.
Reasons for Conservation Programmes
- Maintaining Biodiversity: Ecosystems are more stable when they have high biodiversity.
- Reducing Extinction: Preventing the permanent loss of unique species.
- Protecting Vulnerable Ecosystems: Ensuring habitats like coral reefs or rainforests don't collapse.
- Maintaining Ecosystem Functions:
- Nutrient Cycling: E.g., Carbon and Nitrogen cycles.
- Resource Provision: Providing food, fuel, and genes (for crop breeding).
- Drugs: Many medicines (like aspirin) were originally discovered in wild plants.
Advanced Captive Breeding (AI and IVF)
When endangered animals are difficult to breed naturally or are in different locations:
- Artificial Insemination (AI): Collecting semen from a male and inserting it into the female's reproductive tract.
- In Vitro Fertilisation (IVF): Fertilising an egg with sperm in a laboratory ("in glass") and then implanting the embryo into a female.
- Benefit: These allow for "genetic exchange" between zoos without the stress of moving the physical animals.
Risks of Small Populations
If a population size decreases significantly, the genetic variation of the species decreases.
- Low genetic variation means the species is less likely to survive a change in the environment or a new disease.
- Inbreeding becomes more common, which can lead to harmful genetic defects.
Key Equations
While there are few specific equations for conservation, you are often required to calculate Percentage Change in population sizes:
$$\text{Percentage Change} = \frac{\text{New Value} - \text{Old Value}}{\text{Old Value}} \times 100$$
Common Mistakes to Avoid
- ❌ Wrong: Thinking a "sustainable resource" is one that lasts forever regardless of use.
- ✅ Right: It only lasts forever if the rate of removal does not exceed the rate of production.
- ❌ Wrong: Using the term "Global Warming" as a synonym for "Habitat Destruction."
- ✅ Right: Global warming is a cause of habitat destruction/climate change, but they are distinct concepts in an exam.
- ❌ Wrong: Suggesting that making a species "extinct" is the same as "endangered."
- ✅ Right: Extinct is gone forever; endangered is at risk but still exists.
Exam Tips
- Command Words:
- If the question says "State," give a short, direct answer (e.g., "Seed banks").
- If it says "Explain," you must give a reason (e.g., "Large mesh sizes allow young fish to escape so that they can reach reproductive age").
- Contexts: Expect questions about the Atlantic Cod (fish stocks) or Tropical Rainforests (deforestation).
- Ecosystem Services: When asked why we should conserve plants, always mention their potential for new medicines or as a source of genes for future crop engineering.
- Values: Be prepared to interpret graphs showing population declines over time (e.g., years 1950 to 2020). Ensure you read the axes carefully!