The Impact of Agriculture

Introduction

Since it uses the most land and water, and employs the most people globally, the agricultural sector has a significant influence. Hence, the sector bears a heavy responsibility for the environment in addition to feeding the growing global population. Further effects may result from the push to maximise resource consumption and production efficiency. How do poor agricultural management practices affect the environment?

Overuse of Insecticides and Herbicides

The use of chemical sprays to reduce weed and insect populations has increased yield and prevented food loss during storage. Overuse, however, can result in issues with output going forward.

When an insecticide chemical is used frequently, the pest population may develop resistance to it. This implies that not every target pest is now killed by harmful chemicals. Herbicide resistance is caused by the same principle.

The image below demonstrates how resistance develops. A pest must go through several generations before developing complete resistance. Yet, many pests, like insects, have exceptionally short life cycles, meaning several generations can happen in as little as a few weeks.

How resistance to an insecticide occurs

Farmers typically apply a higher dose to improve the effect if an insect can no longer be efficiently controlled by an insecticide. While it might be effective in the short run, this can hasten the development of pesticide resistance. The best course of action for farmers is to employ a variety of pesticides so that, in the event that pest resistance develops to one product, another chemical will likely still be toxic to the pest.

Herbicides and insecticides can potentially have unanticipated negative effects on the ecosystem. In the case of pesticides, their use has the potential to kill beneficial insects like bees, which will have an impact on plant pollination. Due to the fact that many animals eat insects, a change in the availability of insects may also have an effect on the larger food web.

Spray drift can be a problem with pesticides and herbicides, as the chemical may hit a target it wasn't meant for and harm the environment. Herbicides can linger in the soil for a long enough time to impede the development of other plants. Insecticides and herbicides can leak into rivers and lakes during periods of heavy rainfall, harming other organisms. There is some proof that herbicides can affect soil organisms like fungi and microscopic animals, which affects the food chain.

These issues do not only affect plants. In many countries, routine medication is provided to livestock – not because the animals are ill, but rather to stop infections from happening. If done properly, this is a good technique, but if done excessively, issues may arise. Antibiotics are frequently administered to animals as part of their treatment. Humans are given the same products or ones that are fairly similar. These antibiotics run the same danger of developing resistance as insecticides, making them less likely to control disease and putting both humans and livestock at higher risk of illness or death.

Lesson Overview

Duration: 90 minutes
Class size: 7 students
Age group: Year 10
Subject Area: Other (linked to Geography/Science themes within National Curriculum)
Topic: Impact of agriculture on the environment focussing on overuse of insecticides, herbicides and antibiotics, and resistance development

National Curriculum Links

Key Stage 4 Geography (Year 10):
- Topic: The UK’s evolving physical and human landscapes and wider global context
- Understanding human impact on environment and sustainability.
- Geographical concepts: Cause and consequence, sustainability, environmental impact
Key Stage 4 Science (Biology) - Year 10:
- Biology: Understanding ecosystems, human impact, biodiversity, and antibiotic resistance, including selective breeding, genetic variation and evolution (Year 10 curriculum content).
Cross-curricular links:
- Environmental awareness, citizenship (responsible practices in agriculture), literacy (scientific vocabulary), and critical thinking.

Learning Objectives

By the end of the lesson students will be able to:

Explain how the overuse of insecticides and herbicides leads to pesticide resistance using scientific concepts of evolution and natural selection.
Describe the ecological consequences of pesticide resistance including its effects on food chains and ecosystems.
Identify and explain problems linked to antibiotic use in livestock and relate this to human antibiotic resistance.
Evaluate sustainable farming practices that can reduce the negative environmental impacts caused by poor agricultural management.
Apply scientific reasoning to case studies regarding pesticide resistance and antibiotic use in agriculture.

Resources and Materials

Whiteboard and markers
Printed dyslexia-friendly fact sheets summarising resistance development (large font, coloured overlays optional)
Image sequence showing development of insecticide resistance (based on provided diagram described)
Case studies handouts (differentiated versions)
Interactive group activity materials (scenario cards)
Video clip (5 mins) on sustainable agricultural practices – with subtitles
Writing materials and laptops/tablets (optional) for extension activities

Lesson Structure

1. Engage and Introduction (15 minutes)

Begin with a thought-provoking question: "How do farmers keep pests away from crops? What could possibly go wrong?"
Show a concise video clip explaining pest control and introduce terms: insecticides, herbicides, antibiotic use in animals.
Review learning objectives clearly on board.
Dyslexia-friendly reading: Provide a summary sheet with key vocabulary and definitions with visuals to support understanding.

2. Exploration and Explanation (25 minutes)

Present the diagram of resistance development (selective pressure and generations).
Use clear step-by-step explanation: how frequent insecticide use leads to resistant pests through natural selection.
Ask the class: "What happens when farmers increase pesticide doses?" (Discuss short-term vs long-term effects).
Explore ecological impacts via a mind map activity on the board: effects on bees, soil organisms, food chains, and aquatic systems due to spray drift and runoff.
Discuss antibiotic overuse in livestock and resistance parallels with pesticides.

3. Group Activity: Scenario-based Roleplay (30 minutes)

Split class into small groups (2-3 students). Each group receives a scenario card: e.g. "You are farmers with a pest outbreak resistant to traditional pesticides."
Tasks:
- Identify challenges in their scenario
- Propose sustainable solutions (based on knowledge e.g. pesticide rotation, biological controls, reduced antibiotic use)
Groups present their strategies to the class in 5-minute presentations.
Teacher facilitates discussion: encouraging scientific vocabulary, critical thinking, and considering environmental impact.

4. Reflection and Assessment (15 minutes)

Students complete a short written task (dyslexia-friendly template available) responding to:
"Explain why overusing insecticides and antibiotics can be harmful to the environment and human health, and describe one sustainable method to reduce these harms."
Use formative assessment to identify misconceptions and provide immediate verbal feedback.

5. Extension Activities for Advanced Learners

Research the development of integrated pest management (IPM) and write a brief report with advantages/disadvantages.
Investigate global case studies of antibiotic resistance affecting human health and produce a fact sheet or infographic.
Analyse new scientific advances (biopesticides, genetic pest resistance) and discuss ethical and environmental implications.

6. Differentiation Strategies

For learners with additional needs:
- Use dyslexia-friendly reading materials (coloured overlays, large fonts, simple sentence structure).
- Provide key vocabulary sheets with pictorial support before the lesson.
- Give extra time for group activities and written tasks.
- Scaffold explanations with graphic organisers and mind maps.
For EAL students:
- Pre-teach key terms with visuals.
- Use sentence starters in written tasks.
For advanced learners:
- Provide extension activities and encourage deeper research.
- Encourage leadership roles in group discussions.

Assessment & Feedback

Informal assessment through questioning during explanation and group activity.
Written response evaluated against a simple success criteria rubric including: clarity of explanation, use of key vocabulary, understanding of cause-effect relationships.
Peer and teacher feedback during presentations to reinforce scientific accuracy and communication skills.

Homework Suggestion

Write a persuasive letter to a local farmer advising on strategies to reduce pesticide resistance or antibiotic overuse, integrating lesson learning and ecological concerns.

Final Notes

This lesson ties directly into the National Curriculum’s emphasis on understanding human impact on environments and developing sustainability awareness. It combines scientific principles with real-world application, encouraging critical thinking and responsible citizenship. The use of varied teaching strategies and differentiated materials ensures accessibility for all learners, while extension activities provide opportunities to challenge the most able students.