Conservation & biodiversity (Edexcel GCSE Biology Combined Science): Revision Notes

Conservation & biodiversity

Interdependence in Ecosystems

In ecosystems, species are interconnected and depend on each other for food, shelter, and maintaining the environment. This relationship is called interdependence. When the population of one species is affected, it can have a knock-on effect on others.

Example: In a food chain like:

$$\text{algae} \rightarrow \text{zooplankton} \rightarrow \text{sand eel} \rightarrow \text{puffin} \rightarrow \text{arctic skua}$$

If the population of zooplankton declines due to pollution, there will be an overgrowth of algae and a reduction in sand eel and puffin populations.

Ecosystems with higher biodiversity are more stable because they contain multiple species that can perform similar roles. For example, if a puffin's main food source (sand eels) becomes scarce, it can switch to feeding on mollusks or worms, ensuring its survival.

Benefits of Maintaining Biodiversity

Global Importance:

• Biological Resources: Biodiversity is essential for providing food and medicines. Many species serve as direct sources of food for humans or provide compounds used in the development of life-saving medications.
  • Example: Many medicines are derived from plants, animals, or microorganisms found in biodiverse ecosystems, such as tropical rainforests.
• Climate Stability: Biodiverse ecosystems, such as forests, play a role in regulating the climate by storing carbon and maintaining healthy ecosystems that can buffer against environmental changes.

Local Importance:

• Recreation and Tourism: Areas with high biodiversity, such as forests or coral reefs, are popular tourist destinations. These ecosystems provide opportunities for recreation and economic benefits to local communities through tourism.
  • Example: Rainforests and coral reefs attract ecotourism, which can provide income for local populations while also encouraging conservation efforts.
• Ecosystem Services: Biodiversity supports essential ecosystem services such as pollination, water purification, and soil fertility, all of which are critical for human life and agriculture.

Reforestation:

Forests normally have high biodiversity as they contain wide variety of trees/plants which provide food/shelter for many animal species

Deforestation reduces this biodiversity by removing trees (chopping/burning) Reforestation- helps restore them Reforestation programmes need to be carefully planned:

• maximise positive effects
• minimise negative ones Eg) replanting a forest with a variety of tree species will result in higher biodiversity than replanting using only a single type tree

Conservation schemes protect at risk species

Protect biodiversity by preventing species from dying out by:

• Protecting a species natural habitat (so have place to live)
• Protect species in safe areas outside natural habitat (zoos) & introduce captive breeding programmes to increase numbers
• Seed banks to store& distribute seeds of rare endangered plants | Positive effects | | |---|---| | Protects human food supply | Over fishing has greatly reduced fish in seas so conservation programmes ensure future generations will have fish | | Ensures minimal damage to food
  chains | If one species become extinct it will affect all the organisms that feed on & eaten by that species so conserving one species helps others | | Provides future medicines | Many medicines we use come from plants so undiscovered species may contain medicinal chemicals so if they come extinct we could miss out | | Cultural aspects | Could be important to countries cultural heritage | | Ecotourism | People are drawn to visit beasutiful/ unspoilt landscapes with variety of animal/ plants wich helps bring money | | Provides new jobs | Provides employment for locals through these methods |

Programs to Maintain Biodiversity

To mitigate our negative impact and preserve biodiversity, various conservation programmes have been implemented:

1. Breeding Programmes:

• Designed to prevent endangered species from becoming extinct by increasing their populations in controlled environments.

2. Protection of Rare Habitats:

• Safeguarding habitats with unique species to prevent extinction. In some cases, damaged habitats are restored to support existing or reintroduced populations.

3. Reintroduction of Hedgerows and Field Margins:

• Replanting hedgerows around agricultural land to create habitats for a variety of organisms. Field margins are left uncultivated to allow wildflowers and grasses to grow, supporting biodiversity in areas where monoculture (growing only one type of crop) would otherwise limit it.

4. Reduction of Deforestation and Carbon Dioxide Production:

• Efforts to reduce deforestation and lower CO₂ emissions help slow down global warming, which in turn reduces the rate at which habitats are destroyed.

5. Recycling:

• Encouraging recycling over landfill disposal decreases the amount of land required for waste, conserves natural resources, and reduces environmental pollution.