🌱 Study Notes: Use of Biological Resources

Hello future scientist! Welcome to a really important chapter. Biological resources are simply the living things we rely on—plants, animals, fungi, and micro-organisms. We use them for food, medicine, clothing, and much more.

In this chapter, we’re going to learn how we manage these resources efficiently, especially when it comes to feeding a growing world population, and how we make sure they are still around for generations to come. Don’t worry if some concepts seem tricky; we’ll break them down with simple examples!

I. The Need for Increased Food Production

The world population is getting bigger every day! This creates a huge demand for food. Biologists and farmers work together to increase the amount of food produced from the limited land we have.

Key Concept: Yield

The most important term here is yield.

  • Yield means the amount of product (like crops or milk) produced per unit area (like a field) or per animal.
  • To feed more people, we need to increase the yield from farms.

Think of it this way: If your recipe makes 10 cookies, increasing the yield means using the same ingredients (or slightly better ones) to make 15 cookies instead!

Quick Takeaway: We need high yields to sustain a large and growing human population.

II. Modern Farming Methods (Intensive Farming)

To achieve high yields, farmers often use intensive farming techniques. These methods rely heavily on science and technology to control the environment and maximize growth.

1. Use of Fertilizers

Plants need certain minerals (nutrients) from the soil to grow big and strong. When crops are harvested, these nutrients are removed.

  • Fertilizers are substances added to the soil to replace missing mineral ions and provide essential nutrients like nitrates (for protein production and growth) and phosphates (for healthy roots).
  • Adding fertilizers makes crops grow faster and bigger, increasing the yield dramatically.

Analogy: Fertilizers are like vitamins and supplements for plants—they boost health and growth.

🛑 Common Mistake to Avoid:

Too much fertilizer can be washed into rivers and lakes (a process called leaching), causing excessive growth of algae (an algal bloom). This harms the aquatic environment by reducing oxygen levels in the water.

2. Use of Pesticides and Herbicides

Insects, fungi, and weeds love to eat crops! This reduces the amount of food harvested.

  • Pesticides: Chemicals used to kill animal pests, such as insects (insecticides) that eat the crops.
  • Herbicides: Chemicals used to kill unwanted plants (weeds) that compete with the crops for light, water, and nutrients.

By removing competition and pests, more energy goes into growing the crop we want, again increasing the yield.

3. Mechanisation and Controlled Environments
  • Mechanisation: Using large machines (tractors, automated harvesters) allows farmers to work faster and cultivate larger areas of land with fewer people.
  • Controlled Environments: Using polytunnels or glasshouses allows farmers to control conditions like temperature, light, and water supply, minimizing stress and maximizing growth, regardless of the outdoor weather.

Key Takeaway: Modern farming boosts yield using fertilizers (nutrients), pesticides/herbicides (protection), and machinery (efficiency), but we must be aware of the potential environmental damage these chemicals can cause.

III. Selective Breeding (Artificial Selection)

Modern techniques aren't just about chemistry; they're also about genetics! Selective breeding is a crucial biological method used to improve our biological resources.

What is Selective Breeding?

Selective breeding (also called artificial selection) is the process where humans choose organisms with desirable characteristics (traits) and breed them together over several generations to enhance those traits in the offspring.

Unlike natural selection, where nature chooses the 'fittest' to survive, in selective breeding, humans decide which traits are best for our needs.

The Step-by-Step Process

This process works for both plants (like crops) and animals (like livestock).

  1. Identify the Trait: Determine the desired characteristic (e.g., high milk production, fast growth, resistance to disease, sweeter taste).
  2. Select Parents: Choose two individuals (parents) that strongly display the desired trait.
  3. Breed: Allow these selected parents to mate or cross-pollinate.
  4. Select Offspring: From the resulting offspring, select only those individuals that show the desired trait even more strongly.
  5. Repeat: Breed these superior offspring together. Repeat this process over many generations until the desired characteristic is highly pronounced and stable in the population.

Examples of Selective Breeding

  • Cattle: Breeding cows for higher milk yield or faster growth/leaner meat.
  • Crops: Breeding wheat or rice plants that are resistant to common diseases, or those that produce larger grains (higher yield).
  • Pets: Creating different dog breeds (like sheepdogs good at herding).

Did You Know? All the diverse vegetables we eat today, like cabbage, broccoli, cauliflower, and kale, all came from selectively breeding the same wild mustard plant!

Key Takeaway: Selective breeding allows us to create organisms that are more useful to us by focusing on and strengthening specific, desirable characteristics over many generations.

IV. Conservation of Biological Resources

While we are busy increasing yields, we must also ensure we don't destroy the natural biological resources that support life on Earth. Conservation is about protecting and preserving these resources for the future.

The Importance of Biodiversity

Biodiversity means the variety of different species (plants, animals, microorganisms) living in a particular area. It is important because:

  • Every species plays a role in the ecosystem (e.g., pollinating crops, maintaining soil health).
  • A diverse gene pool provides options for the future. If a new disease attacks our current high-yield crops, we might need genes from wilder, disease-resistant ancestors to breed a solution.
Seed Banks: The Biological Safety Net

One critical method of conservation is the use of seed banks.

A seed bank is essentially a large, secure vault used to store seeds from thousands of different plant species, especially wild relatives of crops and endangered plants.

  • How they work: Seeds are dried carefully and then stored at very low temperatures (often below freezing) to keep them dormant and viable (alive) for decades or even centuries.
  • Purpose: They act as a genetic backup. If a particular crop variety is wiped out by disease, climate change, or disaster, the stored seeds can be retrieved and grown again.

Analogy: A seed bank is like saving all your important documents onto an external hard drive and locking it away safely—it’s an essential backup of global plant genetics!

Key Takeaway: Conservation, particularly through maintaining biodiversity and using seed banks, ensures that we have the genetic resources needed to adapt to future challenges like new diseases or environmental changes.


✅ Quick Review: Essential Terms

Make sure you understand these core concepts for your exam:

  • Yield: Output produced per area/animal.
  • Fertilizers: Add nutrients (like nitrates) to increase plant growth.
  • Herbicides/Pesticides: Kill weeds/pests to protect the crop.
  • Selective Breeding: Humans choosing parents to enhance desired traits over generations.
  • Biodiversity: The variety of life; essential for ecosystem stability and future genetic options.
  • Seed Bank: A conservation tool storing seeds at low temperatures as a genetic backup.

You’ve covered how we feed the world and how we protect our biological inheritance. Great work!