Decomposition and Decay

Decomposition is nature's recycling system, and it's happening all around you! Detritivores (like bacteria, fungi, earthworms, and mushrooms) are the organisms that break down dead material and return nutrients to the soil.

For decay to work properly, these decomposers need three key conditions: warmth (so their enzymes work efficiently), oxygen (for respiration), and moisture (for chemical reactions). Think of composting as creating the perfect decay hotel - you trap heat with a lid, add water when needed, and turn the pile to let air in.

Peat bogs show what happens when decay goes wrong. Without enough oxygen, dead plant material doesn't fully decompose, creating peat that stores carbon for thousands of years. When humans drain these areas for farming, all that stored carbon gets released as CO₂.

Quick Tip: In your decay practical, you'll use lipase enzyme to break down milk fats, mimicking how decomposers work in nature!

Ecosystems and Adaptations

Your local park is actually a complex ecosystem where every organism depends on others to survive. A population is all the individuals of one species living together, whilst a community includes all the different species interacting in that habitat.

Competition drives everything - animals fight for food, water, mates, and shelter, while plants compete for light, water, minerals, and space. Adaptations help organisms win these battles through structural changes (like thick fur), behavioural changes (like hibernation), or functional changes (like producing venom).

Some organisms called extremophiles have adapted to survive in incredibly harsh conditions. Thermophiles can handle boiling temperatures, whilst psychrophiles thrive in freezing conditions - they're like nature's superheroes!

Energy flows through trophic levels in food chains, but only about 10% of energy passes from one level to the next. The rest is lost through movement, heat, waste, and uneaten parts.

Remember: Predator-prey populations cycle together, but there's always a delay because reproduction takes time!

Sampling and Field Studies

When scientists want to study biodiversity, they can't count every single organism, so they use sampling techniques to get a representative picture. It's like taking a small slice of cake to judge the whole thing!

Random sampling uses coordinates to avoid bias - you place tape measures at right angles and use random number generators to pick spots for your quadrats. You'll need at least 10 samples covering 10% of your study area to get reliable results.

Transects are brilliant for spotting trends across an area. You lay a line and take samples at regular intervals, which shows how distribution changes from one place to another.

The abundance and distribution of organisms depend on both biotic factors (like competition and predators) and abiotic factors (like temperature and pH). Understanding these patterns helps us see if human activities are damaging ecosystems.

Pro Tip: Always use the formula: (organisms counted ÷ area sampled) × total area = estimated total population

The Carbon Cycle

Carbon is constantly cycling between the atmosphere, living things, and the Earth in an endless loop that's been running for millions of years. Photosynthesis pulls CO₂ from the air and locks it into glucose, whilst respiration releases it back when organisms break down glucose for energy.

When plants and animals die, most decompose and return their carbon to the atmosphere. However, some get buried and fossilised, trapping carbon underground for millions of years as coal, oil, and gas.

Humans have massively disrupted this cycle by burning fossil fuels, which releases ancient carbon back into the atmosphere. Deforestation makes things worse by removing trees that would normally absorb CO₂, plus burning forests adds even more carbon to the air.

Feeding relationships move carbon through food chains as animals eat plants and each other, building up their own biomass from the carbon compounds they consume.

Key Point: The carbon cycle shows how all life on Earth is connected - the carbon in your body could have been in a dinosaur millions of years ago!

Environmental Impact and Solutions

Human activities are causing serious pollution problems across land, water, and air. Eutrophication happens when fertilisers wash into rivers, causing algae blooms that use up all the oxygen and kill aquatic life.

Food security is becoming a major challenge due to increasing population, climate change, new pests, and conflicts that disrupt farming. Modern intensive farming produces more food but can harm animal welfare and increase disease risk.

Biodiversity is crucial for stable ecosystems because it prevents everything from depending on just one food source or habitat type. We're losing biodiversity fast due to habitat destruction and climate change.

Solutions include breeding programmes for endangered species, legal agreements to cut emissions, protecting natural habitats, and creating field margins where wild plants can grow around farms. Biotechnology offers new approaches like golden rice (enriched with vitamin A) and mycoprotein from fungi.

Think About It: Every choice you make - from what you eat to how you travel - affects these global systems!

Sustainable Practices

The fishing industry shows how human activity can crash natural populations through overfishing. Solutions include strict quotas on catch sizes and rules about minimum fish sizes to protect young fish that haven't reproduced yet.

Biotechnology is developing new food sources to reduce pressure on traditional farming. Mycoprotein from the fungus Fusarium creates meat alternatives like Quorn, grown in controlled conditions with glucose syrup as food.

Sustainability means meeting our needs without destroying the environment for future generations. This requires balancing economic needs, environmental protection, and social factors.

Modern farming faces tough choices between efficiency and environmental impact. Intensive farming produces more food but can increase disease risk, reduce animal welfare, and contribute to antibiotic resistance.

Bottom Line: Sustainability isn't just about saving polar bears - it's about ensuring humans have a liveable planet for centuries to come!