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17 Dec 2025
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Life on Earth N5 Biology: Unit 3 Mind Maps Overview
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Katie Maclean
@katiemaclean_nbjv
1 / 3
Environmental Factors and Species Distribution
Ever wondered why polar bears live in the Arctic but not in tropical rainforests? It's all about biotic and abiotic factors that determine where organisms can survive.
Biotic factors are the living influences on organisms - think predation, disease, competition for food, and grazing. These biological interactions shape which species can thrive in any given area. Abiotic factors are the non-living environmental conditions like temperature, pH, soil quality, water availability, and light intensity.
Scientists use indicator species to assess environmental quality. These are organisms whose presence or absence tells us about the health of an ecosystem. For example, lichens indicate clean air quality, whilst their absence suggests pollution.
Quick Tip: Remember biotic = biological (living), abiotic = not biological . Simple!
Researchers measure these factors using various tools like pH meters for acidity, light meters for brightness, and pitfall traps for counting small animals. The key is taking multiple samples and avoiding errors like shadows affecting light readings or forgetting to clean equipment between measurements.
Sustainable Food Production Methods
Modern agriculture faces a massive challenge: feeding billions whilst protecting our planet. Biological control offers a clever solution by using natural predators to control pests, like introducing Argentine moths to tackle invasive Australian cactus.
Genetically modified (GM) crops are engineered to resist pests naturally, reducing the need for harmful pesticides. This makes them more environmentally friendly than conventional crops. Pesticides kill unwanted organisms but cause bioaccumulation - toxic substances building up in food chains, famously affecting birds of prey with DDT poisoning.
Fertilisers contain nitrates that boost crop yields by providing essential nutrients. Plants absorb these nitrates through their roots and convert them into amino acids for protein production. However, leaching occurs when excess fertilisers wash into water systems.
Environmental Alert: Leaching causes algal blooms that block sunlight, killing aquatic plants and creating oxygen-starved dead zones that devastate entire ecosystems.
The two main alternatives to pesticides are biological control and GM crops - both offering sustainable solutions to pest management without environmental damage.
Evolution and Species Formation
Evolution isn't just ancient history - it's happening right now around us! A species is defined as organisms that can interbreed and produce fertile offspring, which explains why horses and donkeys aren't the same species (their offspring, mules, are sterile).
Natural selection drives evolution through a simple process: environmental pressures favour the best-adapted individuals, who survive to reproduce and pass on their advantageous traits. Over time, these favourable alleles become more common in the population.
Speciation occurs when populations become separated by isolation barriers. Geographical barriers like mountains and rivers physically separate groups, whilst behavioural barriers like different courtship rituals prevent mating between populations. Over time, these isolated groups evolve differently and can no longer interbreed.
Mutations - random changes in genetic material - provide the raw material for evolution. Mutagenic agents like radiation and certain chemicals increase mutation rates. Most mutations are harmful or neutral, but occasionally they're advantageous and spread through populations.
Evolution Insight: Variation within species is essential because it allows populations to adapt to changing environmental conditions over time.
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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
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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
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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
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Best app on earth! no words because it’s too good
Thomas R
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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
Life on Earth N5 Biology: Unit 3 Mind Maps Overview
K
Katie Maclean
@katiemaclean_nbjv
Understanding ecology and evolution is crucial for grasping how life on Earth adapts and survives. These concepts explain everything from why certain plants grow in specific locations to how new species develop over millions of years.
Environmental Factors and Species Distribution
Ever wondered why polar bears live in the Arctic but not in tropical rainforests? It's all about biotic and abiotic factors that determine where organisms can survive.
Biotic factors are the living influences on organisms - think predation, disease, competition for food, and grazing. These biological interactions shape which species can thrive in any given area. Abiotic factors are the non-living environmental conditions like temperature, pH, soil quality, water availability, and light intensity.
Scientists use indicator species to assess environmental quality. These are organisms whose presence or absence tells us about the health of an ecosystem. For example, lichens indicate clean air quality, whilst their absence suggests pollution.
Quick Tip: Remember biotic = biological (living), abiotic = not biological . Simple!
Researchers measure these factors using various tools like pH meters for acidity, light meters for brightness, and pitfall traps for counting small animals. The key is taking multiple samples and avoiding errors like shadows affecting light readings or forgetting to clean equipment between measurements.
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Sustainable Food Production Methods
Modern agriculture faces a massive challenge: feeding billions whilst protecting our planet. Biological control offers a clever solution by using natural predators to control pests, like introducing Argentine moths to tackle invasive Australian cactus.
Genetically modified (GM) crops are engineered to resist pests naturally, reducing the need for harmful pesticides. This makes them more environmentally friendly than conventional crops. Pesticides kill unwanted organisms but cause bioaccumulation - toxic substances building up in food chains, famously affecting birds of prey with DDT poisoning.
Fertilisers contain nitrates that boost crop yields by providing essential nutrients. Plants absorb these nitrates through their roots and convert them into amino acids for protein production. However, leaching occurs when excess fertilisers wash into water systems.
Environmental Alert: Leaching causes algal blooms that block sunlight, killing aquatic plants and creating oxygen-starved dead zones that devastate entire ecosystems.
The two main alternatives to pesticides are biological control and GM crops - both offering sustainable solutions to pest management without environmental damage.
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Evolution and Species Formation
Evolution isn't just ancient history - it's happening right now around us! A species is defined as organisms that can interbreed and produce fertile offspring, which explains why horses and donkeys aren't the same species (their offspring, mules, are sterile).
Natural selection drives evolution through a simple process: environmental pressures favour the best-adapted individuals, who survive to reproduce and pass on their advantageous traits. Over time, these favourable alleles become more common in the population.
Speciation occurs when populations become separated by isolation barriers. Geographical barriers like mountains and rivers physically separate groups, whilst behavioural barriers like different courtship rituals prevent mating between populations. Over time, these isolated groups evolve differently and can no longer interbreed.
Mutations - random changes in genetic material - provide the raw material for evolution. Mutagenic agents like radiation and certain chemicals increase mutation rates. Most mutations are harmful or neutral, but occasionally they're advantageous and spread through populations.
Evolution Insight: Variation within species is essential because it allows populations to adapt to changing environmental conditions over time.
We thought you’d never ask...
What is the Knowunity AI companion?
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.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
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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