Natural Selection and Evolution: A Comprehensive Guide for Students
A... Show more
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
96
4
Lara <3
8/1/2025
Biology
Evolution and Natural Selection Detailed Notes
2,040
•
Aug 1, 2025
•
Detailed Notes on Evolution and Natural Selection for Year 7-9 PDF | KS3 & GCSE
Three Examples of Evolution
This page delves into three classic examples of evolution observed in nature, providing natural selection examples that are often used in KS3 and GCSE Biology curricula.
Darwin's Finches
Darwin's observations of finches in the Galápagos Islands played a crucial role in developing his theory of evolution. He noted 13 different species with variations in their beaks, intelligence, colors, and diets, all adapted to their specific habitats.
Example: Finches developed different beak shapes to suit their diets:
- Sharp beaks for piercing insects or chopping vegetation
- Large, strong beaks for cracking seeds and nuts
- Small beaks for handling smaller seeds
Peppered Moths
The peppered moth case study is a classic example of natural selection taught in schools. Before the Industrial Revolution, these moths were pale to blend with light-colored tree bark. However, as pollution darkened the environment, a mutation allowing for darker coloration became advantageous.
Highlight: Over time, the population shifted from predominantly light-colored moths to dark-colored moths, demonstrating evolution in response to environmental changes.
Flightless Birds
The evolution of flightless birds like penguins, emus, and ostriches provides an interesting example of how species can lose traits that are no longer necessary for survival.
Example: Ostriches and emus evolved large bodies and feet for running on land, while penguins adapted their wings into flippers for swimming, both losing the ability to fly in the process.
This page effectively illustrates how natural selection leads to evolution, providing concrete examples that help students understand these complex concepts.
Peacocks and Sexual Selection
This page focuses on the evolution of peacocks, presenting a case study that challenged Darwin's initial understanding of natural selection and led to the concept of sexual selection.
Peacock Evolution Case Study
The evolution of peacocks' vibrant feathers is presented in a step-by-step process:
- Many male peacocks were initially dull and colorless.
- Females showed little interest in these bland males.
- Colorless males died without producing offspring, decreasing the population.
- Females mated with the more colorful male variants.
- The genes for vibrant feathers were passed down to offspring.
- Over time, the population increased with more colorful males being born.
Highlight: This case study demonstrates how sexual selection, a form of natural selection based on mating preferences, can drive evolution.
Darwin's Theory and the Peacock's Feathers
The page concludes with an interesting anecdote about Darwin's struggle to reconcile the peacock's elaborate feathers with his theory of natural selection.
Quote: Darwin wrote in April 1860, "Just the sight of a feather makes me sick!"
This example illustrates how scientific theories evolve as new evidence challenges existing ideas, an important lesson for students learning about the nature of science.
Vocabulary: Sexual selection - A type of natural selection where members of one biological sex choose mates of the other sex to mate with (intersexual selection), or where members of the same sex compete against each other for mating opportunities (intrasexual selection).
This page provides an excellent opportunity for students to understand how evolution and natural selection can be driven by factors beyond simple survival advantages, enriching their comprehension of evolutionary processes for KS3 and GCSE Biology.
Page 4: Scientific Evidence for Evolution
This section presents the scientific evidence supporting Darwin's theory of natural selection with example. Multiple forms of evidence are discussed, including fossils, extinction patterns, and genetic similarities.
Vocabulary: Peer review - scientific verification process by other experts in the field.
Highlight: Key evidence includes:
- Fossil records showing species development
- Extinction patterns demonstrating survival of the fittest
- Antibiotic resistance showing real-time evolution
- DNA similarities between related species
- Embryological development patterns
Evolution and Natural Selection
This page introduces the fundamental concepts of evolution and natural selection, two of Darwin's most influential theories that have shaped our understanding of life on Earth.
Evolution is explained as the process by which all organisms descended from a common ancestor, likely a prokaryotic bacteria. Over millions of years, organisms adapted their genes to suit various environments and habitats, leading to changes in appearance, behavior, and diet.
Definition: Evolution is the gradual change in the characteristics of a species over time, resulting from the inheritance of genetic variations across generations.
The process of evolution is outlined in four key steps:
- Organisms show variations in their genes
- Those with characteristics suited to their environment survive and reproduce
- Successful genes are passed down to offspring
- This process repeats over time, potentially leading to new species
Example: The image provided illustrates human evolution from primates, showing changes in physical appearances and skull structures over time.
Natural selection, often referred to as "survival of the fittest," is described as the mechanism driving evolution. It involves species adapting to their environment's conditions over generations.
Highlight: Natural selection results in the survival and reproduction of individuals with advantageous traits, while those less adapted may die out or become extinct.
Vocabulary: Mutation - A change in genetic material that can be either advantageous or disadvantageous for an organism's survival.
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
Where can I download the Knowunity app?
You can download the app in the Google Play Store and in the Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.9/5
App Store
4.8/5
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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
Detailed Notes on Evolution and Natural Selection for Year 7-9 PDF | KS3 & GCSE
Natural Selection and Evolution: A Comprehensive Guide for Students
A detailed exploration of Darwin's revolutionary theories of evolution and natural selection, explaining how organisms adapt and evolve over time through genetic variations and environmental pressures. This guide covers key... Show more
Three Examples of Evolution
This page delves into three classic examples of evolution observed in nature, providing natural selection examples that are often used in KS3 and GCSE Biology curricula.
Darwin's Finches
Darwin's observations of finches in the Galápagos Islands played a crucial role in developing his theory of evolution. He noted 13 different species with variations in their beaks, intelligence, colors, and diets, all adapted to their specific habitats.
Example: Finches developed different beak shapes to suit their diets:
- Sharp beaks for piercing insects or chopping vegetation
- Large, strong beaks for cracking seeds and nuts
- Small beaks for handling smaller seeds
Peppered Moths
The peppered moth case study is a classic example of natural selection taught in schools. Before the Industrial Revolution, these moths were pale to blend with light-colored tree bark. However, as pollution darkened the environment, a mutation allowing for darker coloration became advantageous.
Highlight: Over time, the population shifted from predominantly light-colored moths to dark-colored moths, demonstrating evolution in response to environmental changes.
Flightless Birds
The evolution of flightless birds like penguins, emus, and ostriches provides an interesting example of how species can lose traits that are no longer necessary for survival.
Example: Ostriches and emus evolved large bodies and feet for running on land, while penguins adapted their wings into flippers for swimming, both losing the ability to fly in the process.
This page effectively illustrates how natural selection leads to evolution, providing concrete examples that help students understand these complex concepts.
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
Peacocks and Sexual Selection
This page focuses on the evolution of peacocks, presenting a case study that challenged Darwin's initial understanding of natural selection and led to the concept of sexual selection.
Peacock Evolution Case Study
The evolution of peacocks' vibrant feathers is presented in a step-by-step process:
- Many male peacocks were initially dull and colorless.
- Females showed little interest in these bland males.
- Colorless males died without producing offspring, decreasing the population.
- Females mated with the more colorful male variants.
- The genes for vibrant feathers were passed down to offspring.
- Over time, the population increased with more colorful males being born.
Highlight: This case study demonstrates how sexual selection, a form of natural selection based on mating preferences, can drive evolution.
Darwin's Theory and the Peacock's Feathers
The page concludes with an interesting anecdote about Darwin's struggle to reconcile the peacock's elaborate feathers with his theory of natural selection.
Quote: Darwin wrote in April 1860, "Just the sight of a feather makes me sick!"
This example illustrates how scientific theories evolve as new evidence challenges existing ideas, an important lesson for students learning about the nature of science.
Vocabulary: Sexual selection - A type of natural selection where members of one biological sex choose mates of the other sex to mate with (intersexual selection), or where members of the same sex compete against each other for mating opportunities (intrasexual selection).
This page provides an excellent opportunity for students to understand how evolution and natural selection can be driven by factors beyond simple survival advantages, enriching their comprehension of evolutionary processes for KS3 and GCSE Biology.
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
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
Page 4: Scientific Evidence for Evolution
This section presents the scientific evidence supporting Darwin's theory of natural selection with example. Multiple forms of evidence are discussed, including fossils, extinction patterns, and genetic similarities.
Vocabulary: Peer review - scientific verification process by other experts in the field.
Highlight: Key evidence includes:
- Fossil records showing species development
- Extinction patterns demonstrating survival of the fittest
- Antibiotic resistance showing real-time evolution
- DNA similarities between related species
- Embryological development patterns
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 Natural Selection
This page introduces the fundamental concepts of evolution and natural selection, two of Darwin's most influential theories that have shaped our understanding of life on Earth.
Evolution is explained as the process by which all organisms descended from a common ancestor, likely a prokaryotic bacteria. Over millions of years, organisms adapted their genes to suit various environments and habitats, leading to changes in appearance, behavior, and diet.
Definition: Evolution is the gradual change in the characteristics of a species over time, resulting from the inheritance of genetic variations across generations.
The process of evolution is outlined in four key steps:
- Organisms show variations in their genes
- Those with characteristics suited to their environment survive and reproduce
- Successful genes are passed down to offspring
- This process repeats over time, potentially leading to new species
Example: The image provided illustrates human evolution from primates, showing changes in physical appearances and skull structures over time.
Natural selection, often referred to as "survival of the fittest," is described as the mechanism driving evolution. It involves species adapting to their environment's conditions over generations.
Highlight: Natural selection results in the survival and reproduction of individuals with advantageous traits, while those less adapted may die out or become extinct.
Vocabulary: Mutation - A change in genetic material that can be either advantageous or disadvantageous for an organism's survival.
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
Where can I download the Knowunity app?
You can download the app in the Google Play Store and in the Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.9/5
App Store
4.8/5
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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
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
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
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
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
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 app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user