Welcome to the Living Environment: Conservation of Biodiversity
Hello! In this chapter, we are going to explore why the variety of life on Earth (biodiversity) is so important and what we can do to protect it. Think of biodiversity as the Earth's "life support system." If we lose too many parts, the whole system starts to fail. Whether you are aiming for an A* or just trying to get your head around the basics, these notes will break everything down into simple, manageable steps. Let's dive in!
1. Why is Biodiversity Important?
It’s easy to think conservation is just about saving cute animals like pandas, but it’s actually about resources and services that keep humans alive and our economy running.
Resources for the Future
Nature provides us with raw materials we use every day:
• Wood: Used for building houses and furniture.
• Fibres: Cotton from plants or wool from animals for clothes.
• Oils: Vegetable oils for cooking and industrial use.
• Fuels: Biofuels like ethanol from corn or wood chips.
• New Foods: Many wild plants could become future crops if we protect them.
Biomimetics: Copying Nature’s Homework
Biomimetics is when humans copy the designs of living things to solve our own engineering problems.
Example: Scientists studied the ultrasound used by bats to improve medical scans, or the shape of bird wings to design more efficient vehicles. If a species goes extinct, we lose that "blueprint" forever!
Medicines and Research
Many of our new medicines come from chemicals found in wild plants and animals. For example, some plants produce poisons to stop insects eating them; we can turn those poisons into life-saving drugs. Also, some animals are better than humans for physiological research because their bodies work in ways that are easier for scientists to study.
Genetic Resources and CWRs
Our farm crops often get weak or diseased. To fix this, we look for Crop Wild Relatives (CWRs). These are the "wild cousins" of our food. They have "strong" genes that can resist drought or pests. We find these in Centres of Diversity (also called Vavilov Centres), which are areas where many wild relatives of a crop naturally grow.
Ecosystem Services
Living things do "jobs" for us for free:
• Atmospheric composition: Plants balance oxygen and carbon dioxide levels.
• Biogeochemical cycles: Living things recycle nutrients like nitrogen and carbon so they don't run out.
• Interspecies relationships: Bees pollinate our food, and birds disperse seeds so forests can grow.
• Soil maintenance: Earthworms and bacteria create healthy soil and prevent it from washing away (erosion).
Quick Review: Why save a random weed? It might have the genes to save our wheat crops (CWR) or the chemical for a new cancer drug!
2. How Humans Influence Biodiversity
Unfortunately, human activity is causing species to disappear faster than ever. We do this in three main ways:
Direct Exploitation
This is when we take too many individuals from the wild. We exploit them for:
• Food: Overfishing or hunting bushmeat.
• Fashion: Furs, skins, and feathers.
• Entertainment: Taking exotic animals for pets or circuses.
• Traditional Medicines: Using rhino horn or tiger bone (even if they don't actually work!).
Deliberate Eradication
Sometimes we kill animals on purpose because they are "pests" or "competitors." Farmers might kill wolves to protect sheep, or kill insects that eat crops.
Changing the Environment (Abiotic and Biotic Factors)
We change the Abiotic (non-living) features of a habitat:
• Water: Draining wetlands or flooding areas with dams.
• Light: Clearing forests lets too much light onto the forest floor.
• pH and Temp: Pollution can make water acidic or too warm for fish to survive.
We also change Biotic (living) factors:
• Introduced Species: Bringing a new species to an area where it doesn't belong (like grey squirrels in the UK) can wipe out local species.
• Habitat Destruction: Deforestation, building cities (urbanisation), and mining physically remove the homes of wildlife.
Key Takeaway: Humans don't just kill animals directly; we often destroy their "life support" (abiotic factors) or take away their "neighbors" (biotic factors).
3. Methods of Conserving Biodiversity
Don't worry if this seems like a lot to remember! The syllabus breaks it down into priorities and actions.
Setting Priorities: The IUCN
The International Union for Conservation of Nature (IUCN) helps us decide who to save first using several criteria:
• The Red List: A list that categorises species based on how close they are to extinction.
• Evolutionary Uniqueness: EDGE species are those that have no close relatives—if they die, a whole branch of the "tree of life" is gone.
• Endemic Species: Species found in only one specific place on Earth.
• Keystone Species: Species that the whole ecosystem depends on. If they go, the system crashes.
• Flagship Species: "Cute" animals (like pandas) used to raise money and awareness.
Legislation and Protocols
Governments pass laws to help. In the UK, the Wildlife and Countryside Act (1981) protects habitats by creating:
• SSSIs (Sites of Special Scientific Interest).
• NNRs (National Nature Reserves).
Internationally, CITES controls the trade of endangered species.
• Appendix I: Total ban on trade (e.g., Gorillas).
• Appendix II: Trade is allowed but strictly controlled (e.g., certain orchids).
Captive Breeding and Release (CBR)
When a species is almost gone, we use ex-situ conservation (protecting them outside their natural home, like in a zoo).
• Methods: We use artificial insemination or embryo transfer to increase numbers.
• Release: Soft release involves giving animals food and shelter while they get used to the wild. Hard release is when they are released with no further help.
Habitat Conservation
The best way to save species is in-situ conservation (protecting them in their natural home).
• Habitat Creation: Building new wetlands or planting forests.
• Rewilding: Restoring a habitat to its natural state.
• Biological Corridors: Connecting small "islands" of habitat so animals can move between them safely.
Memory Aid: Remember I-S vs E-S. In-situ = In the natural place. Ex-situ = Exit the natural place.
4. Ecological Terminology and Succession
To be a good scientist, you need the right words!
Key Terms
• Species: Organisms that can breed to produce fertile offspring.
• Ecological Niche: The "job" or role an organism has in its habitat.
• Population: All the members of one species in an area.
• Community: All the different species living together in an area.
• Ecosystem: The community plus the abiotic (non-living) environment.
Ecological Succession
Succession is the story of how a habitat changes over time. It starts with pioneer species (tough plants like lichens) that can grow on bare rock. They die and create soil, allowing bigger plants to grow. This continues through several seres (stages) until it reaches a stable climax community (usually a forest).
If humans stop this process (e.g., by mowing a lawn or grazing sheep), we create a plagioclimax. This is a "blocked" stage of succession that stays the same because we keep interfering. Many rare species live in plagioclimax habitats (like wildflower meadows), so we have to keep grazing or mowing to protect them!
Quick Review:
1. Pioneer species (start)
2. Seres (middle stages)
3. Climax community (stable end point)
4. Plagioclimax (humans holding it in one stage)
5. Population Dynamics: r- and k- Selection
Not all species grow the same way. Scientists categorise them into two "strategies":
r-selected species
• They focus on quantity.
• They have many offspring, but provide very little care.
• Most offspring die young, but the population can grow very fast.
Example: Mice, weeds, or fish.
k-selected species
• They focus on quality.
• They have very few offspring and provide lots of care.
• They are much more likely to go extinct because they can't recover their numbers quickly if they are hunted.
Example: Whales, elephants, and humans.
Common Mistake: Students often think r-selected species are "better" because they have more babies. Actually, both are successful strategies for different environments! However, k-selected species are usually the ones that need the most conservation help.
6. Measuring Biodiversity
To see if our conservation is working, we need to measure it. One common way is Simpson’s Index of Diversity.
The formula is: \( D = \frac{N(N-1)}{\sum n(n-1)} \)
Where:
• \( N \) = total number of organisms of all species found.
• \( n \) = number of individuals of a particular species.
A high score means the habitat is healthy and diverse. A low score means it is under stress or dominated by just one or two species.
Key Takeaway: Conservation isn't just about feelings; it's about data. We use maths and new technology like eDNA (finding DNA in water samples) and satellite tracking to monitor our progress.
Final Summary: The Living Environment
• Biodiversity provides resources (wood, food) and services (pollination, oxygen).
• Humans threaten biodiversity through exploitation, habitat destruction, and introducing new species.
• We save species using laws (CITES), captive breeding (zoo programs), and habitat protection (SSSIs).
• Managing succession (plagioclimax) is vital for many rare habitats.
• Different species require different help (r-strategists vs k-strategists).
You've got this! Keep reviewing these terms, and you'll be an expert in no time.