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Organisms respond to changes in their internal and external environments (a-level only)
Biological molecules
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Britain & the wider world: 1745 -1901
1l the quest for political stability: germany, 1871-1991
The cold war
Inter-war germany
Medieval period: 1066 -1509
2d religious conflict and the church in england, c1529-c1570
2o democracy and nazism: germany, 1918-1945
1f industrialisation and the people: britain, c1783-1885
1c the tudors: england, 1485-1603
2m wars and welfare: britain in transition, 1906-1957
World war two & the holocaust
2n revolution and dictatorship: russia, 1917-1953
2s the making of modern britain, 1951-2007
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Biology
4 Dec 2025
314
32 pages
Molly Hutton @mollyhutton
With the world's population exploding past 8 billion people, feeding everyone has become one of our biggest challenges.... Show more
You're diving into one of the most relevant topics in modern biology - how we're going to feed our growing planet! Food production sits within the "Life on Earth" unit of your N5 Biology course, alongside other key areas like ecosystems, photosynthesis, and evolution.
This knowledge area focuses on the science behind modern farming methods. You'll discover why farmers rely on chemicals to boost their harvests and what happens when these chemicals escape into the environment.
Quick Tip This topic connects directly to current environmental issues you hear about in the news, making it perfect for exam questions about real-world applications!
The numbers don't lie - human population has skyrocketed from under 2 billion in 1900 to over 8 billion today. Every single one of these people needs food, which means farmers must produce way more crops than ever before.
Food yield is simply the amount of crop harvested for food from a given area. Think of it as getting the maximum bang for your buck from every field. As the population curve shoots upward, so must our food production.
This pressure has pushed farmers towards two main solutions fertilisers (which feed plants the nutrients they crave) and pesticides (which eliminate anything trying to destroy crops). Both work brilliantly - but they come with serious strings attached.
Remember The key relationship here is simple - more people = need for more food = increased use of agricultural chemicals.
Here's the science bit that's actually quite clever plants absorb nitrates from soil water through their roots, then convert these into amino acids, which build up into proteins. It's like giving plants their essential vitamins!
When farmers add fertilisers containing nitrates to soil, they're basically creating a nutrient-rich buffet for their crops. More nitrates mean more proteins, which translates directly into bigger, healthier plants and higher yields.
Animals get their amino acids by munching on plants (or other animals), so this nitrogen boost ripples up through the entire food chain. Without enough nitrates in soil, crops struggle to grow properly - a bit like trying to build muscle without eating enough protein.
Exam Tip You don't need to memorise the full nitrogen cycle, but understanding this nitrate → amino acid → protein pathway is essential for your exams.
Unfortunately, fertilisers don't stay put where farmers want them. They leach into rivers and lakes, creating an environmental disaster called eutrophication that you absolutely need to understand for exams.
Here's the deadly sequence excess nitrates cause algal blooms (massive algae growth) → these block sunlight → aquatic plants die → bacteria feast on all the dead material → bacteria use up loads of oxygen → fish and other organisms suffocate.
It's like overcrowding a party - initially exciting, but ultimately everything goes wrong. The water becomes a lifeless, stinking mess that can take years to recover.
Genetically modified (GM) crops offer one solution by reducing fertiliser dependence, though this remains controversial.
Key Point Learn this eutrophication sequence step-by-step - it's a classic exam question that trips up loads of students!
Pesticides seem brilliant at first - they eliminate crop-damaging pests and boost yields dramatically. However, they don't just disappear after doing their job. Instead, they stick around in the environment, building up in organisms through bioaccumulation.
As these toxins pass along food chains, they become more concentrated at each level. A tiny amount on plants becomes deadly by the time it reaches top predators - imagine a snowball rolling downhill, getting bigger and more dangerous.
Fortunately, farmers have alternatives biological control (using natural predators instead of chemicals) and GM crops (engineered to resist pests naturally). These methods work with nature rather than against it.
Real-World Connection This bioaccumulation process famously nearly wiped out birds of prey like eagles - their eggshells became so thin they couldn't reproduce successfully.
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
6
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the essential roles of glucose in respiration, photosynthesis, and metabolism. Understand how environmental factors like light intensity, temperature, and carbon dioxide concentration affect photosynthesis rates. This summary covers aerobic and anaerobic respiration, including equations and practical investigations for GCSE AQA biology.
BiologyHigher tier combined science flashcards about topics on Biology paper 1
BiologyExplore the Nitrogen Cycle's key processes, including nitrogen fixation, the role of natural and artificial fertilizers, and methods for restoring soil fertility. This summary covers essential concepts for GCSE Biology, focusing on nutrient cycles, plant nutrition, and the impact of fertilizers on agriculture and the environment.
BiologyExplore the characteristics and diversity of living organisms, including prokaryotes and eukaryotes. This summary covers essential biological processes, cellular structures, and the role of pathogens. Ideal for Edexcel IGCSE Biology revision.
BiologyExplore the critical concepts of sustainable food production, including the nitrogen cycle, eutrophication, and the role of genetically modified organisms (GMOs) in enhancing crop yield. This summary covers the impact of population growth on food resources, the use of fertilizers and pesticides, and alternative pest control methods. Ideal for biology students seeking to understand the complexities of agricultural practices and their environmental implications.
BiologyExplore the intricate relationships within ecosystems through the Carbon and Nitrogen Cycles. This summary covers key concepts such as energy transfer, trophic levels, and the roles of various organisms in nutrient cycling. Ideal for students studying ecology and environmental science.
BiologyApp Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Molly Hutton
@mollyhutton
With the world's population exploding past 8 billion people, feeding everyone has become one of our biggest challenges. This topic explores how farmers are ramping up food production using fertilisers and pesticides, but also reveals the serious environmental costs that... Show more
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
You're diving into one of the most relevant topics in modern biology - how we're going to feed our growing planet! Food production sits within the "Life on Earth" unit of your N5 Biology course, alongside other key areas like ecosystems, photosynthesis, and evolution.
This knowledge area focuses on the science behind modern farming methods. You'll discover why farmers rely on chemicals to boost their harvests and what happens when these chemicals escape into the environment.
Quick Tip: This topic connects directly to current environmental issues you hear about in the news, making it perfect for exam questions about real-world applications!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
The numbers don't lie - human population has skyrocketed from under 2 billion in 1900 to over 8 billion today. Every single one of these people needs food, which means farmers must produce way more crops than ever before.
Food yield is simply the amount of crop harvested for food from a given area. Think of it as getting the maximum bang for your buck from every field. As the population curve shoots upward, so must our food production.
This pressure has pushed farmers towards two main solutions: fertilisers (which feed plants the nutrients they crave) and pesticides (which eliminate anything trying to destroy crops). Both work brilliantly - but they come with serious strings attached.
Remember: The key relationship here is simple - more people = need for more food = increased use of agricultural chemicals.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Here's the science bit that's actually quite clever: plants absorb nitrates from soil water through their roots, then convert these into amino acids, which build up into proteins. It's like giving plants their essential vitamins!
When farmers add fertilisers containing nitrates to soil, they're basically creating a nutrient-rich buffet for their crops. More nitrates mean more proteins, which translates directly into bigger, healthier plants and higher yields.
Animals get their amino acids by munching on plants (or other animals), so this nitrogen boost ripples up through the entire food chain. Without enough nitrates in soil, crops struggle to grow properly - a bit like trying to build muscle without eating enough protein.
Exam Tip: You don't need to memorise the full nitrogen cycle, but understanding this nitrate → amino acid → protein pathway is essential for your exams.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Unfortunately, fertilisers don't stay put where farmers want them. They leach into rivers and lakes, creating an environmental disaster called eutrophication that you absolutely need to understand for exams.
Here's the deadly sequence: excess nitrates cause algal blooms (massive algae growth) → these block sunlight → aquatic plants die → bacteria feast on all the dead material → bacteria use up loads of oxygen → fish and other organisms suffocate.
It's like overcrowding a party - initially exciting, but ultimately everything goes wrong. The water becomes a lifeless, stinking mess that can take years to recover.
Genetically modified (GM) crops offer one solution by reducing fertiliser dependence, though this remains controversial.
Key Point: Learn this eutrophication sequence step-by-step - it's a classic exam question that trips up loads of students!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Pesticides seem brilliant at first - they eliminate crop-damaging pests and boost yields dramatically. However, they don't just disappear after doing their job. Instead, they stick around in the environment, building up in organisms through bioaccumulation.
As these toxins pass along food chains, they become more concentrated at each level. A tiny amount on plants becomes deadly by the time it reaches top predators - imagine a snowball rolling downhill, getting bigger and more dangerous.
Fortunately, farmers have alternatives: biological control (using natural predators instead of chemicals) and GM crops (engineered to resist pests naturally). These methods work with nature rather than against it.
Real-World Connection: This bioaccumulation process famously nearly wiped out birds of prey like eagles - their eggshells became so thin they couldn't reproduce successfully.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
6
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the essential roles of glucose in respiration, photosynthesis, and metabolism. Understand how environmental factors like light intensity, temperature, and carbon dioxide concentration affect photosynthesis rates. This summary covers aerobic and anaerobic respiration, including equations and practical investigations for GCSE AQA biology.
BiologyHigher tier combined science flashcards about topics on Biology paper 1
BiologyExplore the Nitrogen Cycle's key processes, including nitrogen fixation, the role of natural and artificial fertilizers, and methods for restoring soil fertility. This summary covers essential concepts for GCSE Biology, focusing on nutrient cycles, plant nutrition, and the impact of fertilizers on agriculture and the environment.
BiologyExplore the characteristics and diversity of living organisms, including prokaryotes and eukaryotes. This summary covers essential biological processes, cellular structures, and the role of pathogens. Ideal for Edexcel IGCSE Biology revision.
BiologyExplore the critical concepts of sustainable food production, including the nitrogen cycle, eutrophication, and the role of genetically modified organisms (GMOs) in enhancing crop yield. This summary covers the impact of population growth on food resources, the use of fertilizers and pesticides, and alternative pest control methods. Ideal for biology students seeking to understand the complexities of agricultural practices and their environmental implications.
BiologyExplore the intricate relationships within ecosystems through the Carbon and Nitrogen Cycles. This summary covers key concepts such as energy transfer, trophic levels, and the roles of various organisms in nutrient cycling. Ideal for students studying ecology and environmental science.
BiologyApp Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Sociology