Ready to dive into the fascinating world of genetics and...
Biology388 views·Updated Jun 11, 2026·5 pagesAQA GCSE Biology Topic 6: Inheritance, Variation & Evolution Notes
H
heather@heatherwu
1 / 5
1
of 5
Reproduction and DNA Basics
Ever wondered how you ended up with your mum's eyes but your dad's nose? It all comes down to meiosis - the special process that creates gametes (sex cells like sperm and eggs). Unlike normal cell division, meiosis creates four genetically different cells, each with half the usual number of chromosomes.
Sexual reproduction needs two parents and creates loads of variation, which helps species survive through natural selection. Asexual reproduction only needs one parent and is much faster - think of how quickly bacteria multiply when you're ill!
Your DNA is basically a twisted ladder (called a double helix) made from four different bases that pair up: C with G, and A with T. Every sequence of three bases codes for one amino acid, and these amino acids link together to make proteins through protein synthesis.
Quick tip: Remember that your genotype is the genetic code you carry, whilst your phenotype is what actually shows up - like having the gene for brown eyes (genotype) and actually having brown eyes (phenotype).
2
of 5
Genetic Disorders and Natural Selection
Some genetic conditions are caused by dominant alleles (like polydactyly, where you're born with extra fingers), whilst others need recessive alleles from both parents (like cystic fibrosis). This is why Punnett squares are so useful - they help predict what characteristics offspring might inherit.
Evolution happens when populations change over time through natural selection. Here's how it works: individuals show variation, those best suited to their environment survive and reproduce more, and they pass their advantageous alleles to their offspring.
Selective breeding lets humans speed up this process by choosing parents with desirable traits. Farmers use this to create disease-resistant crops or cows that produce more milk. However, it can lead to inbreeding, making organisms more vulnerable to diseases.
Remember: A species is defined as organisms that can reproduce together to produce fertile offspring - which is why horses and donkeys are different species (their offspring, mules, are infertile).
3
of 5
Genetic Engineering and Cloning
Genetic engineering sounds like science fiction, but it's happening right now! Scientists can take genes from one organism and put them into another to create desired characteristics. For example, bacteria can be modified to produce human insulin for diabetics.
The process involves using restriction enzymes to cut out specific genes, inserting them into plasmids (tiny DNA circles in bacteria), then using ligase to seal everything together. The modified bacteria then multiply, creating loads of the desired product.
Cloning comes in several forms. Tissue culture and cuttings help preserve rare plants, whilst embryo transplants split early animal embryos before cells specialise. Adult cell cloning is the most complex - scientists remove the nucleus from an unfertilised egg and replace it with a nucleus from an adult cell.
Fascinating fact: Dolly the sheep was created using adult cell cloning, proving that even specialised adult cells contain all the genetic information needed to create a whole organism!
4
of 5
Evolution Scientists and Fossils
Charles Darwin changed everything with his theory of evolution by natural selection, published in "On the Origin of Species". His ideas took time to be accepted because they challenged religious beliefs, lacked sufficient evidence, and scientists didn't yet understand how inheritance worked.
Speciation occurs when populations become geographically separated and face different environmental pressures. Over time, mutations and natural selection cause so many changes that the groups can no longer interbreed - creating new species.
Gregor Mendel discovered the basic principles of inheritance through his plant breeding experiments, showing that characteristics are passed down in distinct "units" (what we now call genes). Fossils provide evidence of evolution, forming when organisms don't fully decay, when minerals replace bones, or when traces like footprints are preserved.
Key point: The fossil record is incomplete because most early organisms were soft-bodied, geological activity destroyed many fossils, and fossilisation requires very specific conditions.
5
of 5
Disease Resistance and Classification
Antibiotics only work against bacteria because they target bacterial cell walls - but viruses don't have cell walls, which is why antibiotics can't cure viral infections like colds. Unfortunately, antibiotic resistance is becoming a major problem as bacterial mutations create strains that survive antibiotic treatment.
MRSA is a dangerous example of antibiotic-resistant bacteria. To slow the development of resistance, doctors shouldn't prescribe antibiotics for minor infections, patients must complete their full course, and agricultural antibiotic use should be limited.
Scientists classify living things using the Linnaean system: Kingdom, Phylum, Class, Order, Family, Genus, Species. This helps us understand relationships between organisms and gives scientists a common language. Carl Woese later proposed the three-domain system, dividing life into Archaea (primitive bacteria in extreme environments), Bacteria (true bacteria), and Eukaryota (everything else with proper cell nuclei).
Study tip: Remember the classification order with "King Philip Came Over For Good Soup" - it's a classic memory trick that actually works!
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?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
Similar content
Most popular content: Genetic Variation
4BiologyAQA Biology: Key Concepts
Explore essential AQA Biology topics including Photosynthesis, Respiration, Homeostasis, Genetics, and Ecology. This comprehensive knowledge organizer covers key concepts such as energy transfer, hormonal control, and genetic variation, providing a solid foundation for your studies. Ideal for exam preparation and understanding biological processes.
108,755305
BiologyGenetics and Evolution Overview
Explore key concepts in genetics and evolution, including inheritance patterns, natural selection, mutations, and genetic engineering. This summary covers essential topics for GCSE Biology, providing insights into biological classification, reproduction methods, and the role of DNA in heredity. Ideal for active recall and exam preparation.
94,159101
BiologyGenetic Engineering & Evolution
Explore the principles of genetic engineering, including the creation of genetically modified organisms (GMOs), therapeutic cloning, and the impact of natural selection on evolution. This summary covers key concepts such as genetic variation, artificial selection, and the role of environmental factors in phenotype expression. Ideal for AQA GCSE Biology students preparing for exams.
1142718
BiologyAQA Biology: Genetic Variation & Evolution
Explore key concepts in AQA Biology Module 4, focusing on genetic variation, evolution, and biodiversity. This summary covers essential topics such as natural selection, mutation types, meiosis, and the processes of transcription and translation. Ideal for exam preparation and understanding biological classification and species diversity.
1258922
Most popular content in Biology
9C
BiologyCell Biology and Cell structure
cell structures
93,1650
BiologyAQA Biology: Key Concepts
Explore essential AQA Biology topics including Photosynthesis, Respiration, Homeostasis, Genetics, and Ecology. This comprehensive knowledge organizer covers key concepts such as energy transfer, hormonal control, and genetic variation, providing a solid foundation for your studies. Ideal for exam preparation and understanding biological processes.
108,755305
T
BiologyThe functions of subcellular structures - B1 Biology
Flashcards on the different functions of subcellular structures: cell membrane, nucleus, mitochondria, ribosomes, cytoplasm, permant vacuole, chloroplasts and cell wall.
102,7205
1
Biology1.cells Gcse biology question cards
combined science higher biology
92,3054
BiologyA-Level Biology Year 1 Overview
Comprehensive summary of AQA A-Level Biology Year 1, covering key topics such as cellular structure, protein synthesis, immune response, gas exchange, and more. Ideal for exam preparation and understanding biological concepts. Includes detailed insights into cellular processes, biological classification, and the circulatory system.
1214,843691
BiologyBiology paper 1 Summary
Notes for Biology paper 1 contains the full course for AQA higher combined!
104,110106
T
BiologyTypes of cells
biology
101,1830
B
BiologyBiology Paper 1 quiz
this is a simple quiz on key knowledge needed for paper 1
102,7405
C
BiologyCells part 1 function of cells.
About cells and function of cells etc.
119771
Most popular content
9
SociologySociology of Education Overview
Explore comprehensive A-Level Sociology notes on the education system, covering key theories, policies, and sociological perspectives. This resource includes insights on marketisation, gender roles, cultural deprivation, and educational inequalities, providing a thorough understanding of how education shapes social stratification and individual achievement. Ideal for exam preparation and in-depth study.
12102,7813,040
SociologySociology of Families: Comprehensive Revision
Dive into an extensive overview of family dynamics, perspectives, and patterns in sociology. This resource covers key concepts such as family diversity, gender roles, marriage, and the impact of social policies on family structures. Perfect for A-Level Sociology students preparing for Paper 2.
1273,5282,306
CriminologyCriminology: Crime & Punishment Overview
Comprehensive mindmaps covering key concepts in the Crime and Punishment topic for WJEC Criminology Unit 4. This resource includes detailed insights into the Criminal Justice System, crime prevention strategies, sentencing models, and the roles of various agencies. Ideal for A-Level revision, ensuring you grasp essential theories and legislative processes to excel in your exams.
1254,8511,059
SociologyComprehensive Crime & Deviance Overview
Explore an extensive revision of crime and deviance topics, including theories, types of crime, and the impact of media. This resource covers key concepts such as Marxism, functionalism, gender and crime, and the influence of globalization on criminal behavior. Ideal for students seeking a thorough understanding of criminology and its various theories. Type: Full Topic Revision.
1251,6261,399
English LiteratureAn Inspector Calls: Character Insights
Explore in-depth analysis and key quotes for characters in J.B. Priestley's 'An Inspector Calls'. This resource covers Gerald Croft, Inspector Goole, Sheila Birling, Mrs. Birling, Eric Birling, and Eva Smith, focusing on themes of class, gender roles, and social responsibility. Ideal for students aiming for Grade 8 and above.
1025,403907
CriminologyWJEC Unit 4 Criminology
Criminology unit 4 detailed revision note
127,142124
C
BiologyCell Biology and Cell structure
cell structures
93,1650
CriminologyCriminology Theories Overview
Explore key criminology theories and their implications on crime and deviance. This comprehensive summary covers biological, psychological, and sociological perspectives, including labelling theory, right realism, and the impact of social campaigns on policy development. Ideal for A-Level criminology students seeking to understand the complexities of criminal behaviour and the factors influencing crime prevention strategies.
129,753210
English LiteratureRomeo and Juliet: Key themes
Key Romeo and Juliet themes and analysed quotes
106,695198
Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.6/5App Store
4.7/5Google 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 SiOS 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 KlichAndroid 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.
AnnaiOS user
Biology388 views·Updated Jun 11, 2026·5 pagesAQA GCSE Biology Topic 6: Inheritance, Variation & Evolution Notes
H
heather@heatherwu
Ready to dive into the fascinating world of genetics and evolution? This topic covers everything from how your cells create the next generation to why Darwin's ideas revolutionised science - and it's more relevant to your daily life than you...
1
of 5
Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
Reproduction and DNA Basics
Ever wondered how you ended up with your mum's eyes but your dad's nose? It all comes down to meiosis - the special process that creates gametes (sex cells like sperm and eggs). Unlike normal cell division, meiosis creates four genetically different cells, each with half the usual number of chromosomes.
Sexual reproduction needs two parents and creates loads of variation, which helps species survive through natural selection. Asexual reproduction only needs one parent and is much faster - think of how quickly bacteria multiply when you're ill!
Your DNA is basically a twisted ladder (called a double helix) made from four different bases that pair up: C with G, and A with T. Every sequence of three bases codes for one amino acid, and these amino acids link together to make proteins through protein synthesis.
Quick tip: Remember that your genotype is the genetic code you carry, whilst your phenotype is what actually shows up - like having the gene for brown eyes (genotype) and actually having brown eyes (phenotype).
2
of 5Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
Genetic Disorders and Natural Selection
Some genetic conditions are caused by dominant alleles (like polydactyly, where you're born with extra fingers), whilst others need recessive alleles from both parents (like cystic fibrosis). This is why Punnett squares are so useful - they help predict what characteristics offspring might inherit.
Evolution happens when populations change over time through natural selection. Here's how it works: individuals show variation, those best suited to their environment survive and reproduce more, and they pass their advantageous alleles to their offspring.
Selective breeding lets humans speed up this process by choosing parents with desirable traits. Farmers use this to create disease-resistant crops or cows that produce more milk. However, it can lead to inbreeding, making organisms more vulnerable to diseases.
Remember: A species is defined as organisms that can reproduce together to produce fertile offspring - which is why horses and donkeys are different species (their offspring, mules, are infertile).
3
of 5Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
Genetic Engineering and Cloning
Genetic engineering sounds like science fiction, but it's happening right now! Scientists can take genes from one organism and put them into another to create desired characteristics. For example, bacteria can be modified to produce human insulin for diabetics.
The process involves using restriction enzymes to cut out specific genes, inserting them into plasmids (tiny DNA circles in bacteria), then using ligase to seal everything together. The modified bacteria then multiply, creating loads of the desired product.
Cloning comes in several forms. Tissue culture and cuttings help preserve rare plants, whilst embryo transplants split early animal embryos before cells specialise. Adult cell cloning is the most complex - scientists remove the nucleus from an unfertilised egg and replace it with a nucleus from an adult cell.
Fascinating fact: Dolly the sheep was created using adult cell cloning, proving that even specialised adult cells contain all the genetic information needed to create a whole organism!
4
of 5Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
Evolution Scientists and Fossils
Charles Darwin changed everything with his theory of evolution by natural selection, published in "On the Origin of Species". His ideas took time to be accepted because they challenged religious beliefs, lacked sufficient evidence, and scientists didn't yet understand how inheritance worked.
Speciation occurs when populations become geographically separated and face different environmental pressures. Over time, mutations and natural selection cause so many changes that the groups can no longer interbreed - creating new species.
Gregor Mendel discovered the basic principles of inheritance through his plant breeding experiments, showing that characteristics are passed down in distinct "units" (what we now call genes). Fossils provide evidence of evolution, forming when organisms don't fully decay, when minerals replace bones, or when traces like footprints are preserved.
Key point: The fossil record is incomplete because most early organisms were soft-bodied, geological activity destroyed many fossils, and fossilisation requires very specific conditions.
5
of 5Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
Disease Resistance and Classification
Antibiotics only work against bacteria because they target bacterial cell walls - but viruses don't have cell walls, which is why antibiotics can't cure viral infections like colds. Unfortunately, antibiotic resistance is becoming a major problem as bacterial mutations create strains that survive antibiotic treatment.
MRSA is a dangerous example of antibiotic-resistant bacteria. To slow the development of resistance, doctors shouldn't prescribe antibiotics for minor infections, patients must complete their full course, and agricultural antibiotic use should be limited.
Scientists classify living things using the Linnaean system: Kingdom, Phylum, Class, Order, Family, Genus, Species. This helps us understand relationships between organisms and gives scientists a common language. Carl Woese later proposed the three-domain system, dividing life into Archaea (primitive bacteria in extreme environments), Bacteria (true bacteria), and Eukaryota (everything else with proper cell nuclei).
Study tip: Remember the classification order with "King Philip Came Over For Good Soup" - it's a classic memory trick that actually works!
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?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
Similar content
Most popular content: Genetic Variation
4BiologyAQA Biology: Key Concepts
Explore essential AQA Biology topics including Photosynthesis, Respiration, Homeostasis, Genetics, and Ecology. This comprehensive knowledge organizer covers key concepts such as energy transfer, hormonal control, and genetic variation, providing a solid foundation for your studies. Ideal for exam preparation and understanding biological processes.
108,755305
BiologyGenetics and Evolution Overview
Explore key concepts in genetics and evolution, including inheritance patterns, natural selection, mutations, and genetic engineering. This summary covers essential topics for GCSE Biology, providing insights into biological classification, reproduction methods, and the role of DNA in heredity. Ideal for active recall and exam preparation.
94,159101
BiologyGenetic Engineering & Evolution
Explore the principles of genetic engineering, including the creation of genetically modified organisms (GMOs), therapeutic cloning, and the impact of natural selection on evolution. This summary covers key concepts such as genetic variation, artificial selection, and the role of environmental factors in phenotype expression. Ideal for AQA GCSE Biology students preparing for exams.
1142718
BiologyAQA Biology: Genetic Variation & Evolution
Explore key concepts in AQA Biology Module 4, focusing on genetic variation, evolution, and biodiversity. This summary covers essential topics such as natural selection, mutation types, meiosis, and the processes of transcription and translation. Ideal for exam preparation and understanding biological classification and species diversity.
1258922
Most popular content in Biology
9C
BiologyCell Biology and Cell structure
cell structures
93,1650
BiologyAQA Biology: Key Concepts
Explore essential AQA Biology topics including Photosynthesis, Respiration, Homeostasis, Genetics, and Ecology. This comprehensive knowledge organizer covers key concepts such as energy transfer, hormonal control, and genetic variation, providing a solid foundation for your studies. Ideal for exam preparation and understanding biological processes.
108,755305
T
BiologyThe functions of subcellular structures - B1 Biology
Flashcards on the different functions of subcellular structures: cell membrane, nucleus, mitochondria, ribosomes, cytoplasm, permant vacuole, chloroplasts and cell wall.
102,7205
1
Biology1.cells Gcse biology question cards
combined science higher biology
92,3054
BiologyA-Level Biology Year 1 Overview
Comprehensive summary of AQA A-Level Biology Year 1, covering key topics such as cellular structure, protein synthesis, immune response, gas exchange, and more. Ideal for exam preparation and understanding biological concepts. Includes detailed insights into cellular processes, biological classification, and the circulatory system.
1214,843691
BiologyBiology paper 1 Summary
Notes for Biology paper 1 contains the full course for AQA higher combined!
104,110106
T
BiologyTypes of cells
biology
101,1830
B
BiologyBiology Paper 1 quiz
this is a simple quiz on key knowledge needed for paper 1
102,7405
C
BiologyCells part 1 function of cells.
About cells and function of cells etc.
119771
Most popular content
9SociologySociology of Education Overview
Explore comprehensive A-Level Sociology notes on the education system, covering key theories, policies, and sociological perspectives. This resource includes insights on marketisation, gender roles, cultural deprivation, and educational inequalities, providing a thorough understanding of how education shapes social stratification and individual achievement. Ideal for exam preparation and in-depth study.
12102,7813,040
SociologySociology of Families: Comprehensive Revision
Dive into an extensive overview of family dynamics, perspectives, and patterns in sociology. This resource covers key concepts such as family diversity, gender roles, marriage, and the impact of social policies on family structures. Perfect for A-Level Sociology students preparing for Paper 2.
1273,5282,306
CriminologyCriminology: Crime & Punishment Overview
Comprehensive mindmaps covering key concepts in the Crime and Punishment topic for WJEC Criminology Unit 4. This resource includes detailed insights into the Criminal Justice System, crime prevention strategies, sentencing models, and the roles of various agencies. Ideal for A-Level revision, ensuring you grasp essential theories and legislative processes to excel in your exams.
1254,8511,059
SociologyComprehensive Crime & Deviance Overview
Explore an extensive revision of crime and deviance topics, including theories, types of crime, and the impact of media. This resource covers key concepts such as Marxism, functionalism, gender and crime, and the influence of globalization on criminal behavior. Ideal for students seeking a thorough understanding of criminology and its various theories. Type: Full Topic Revision.
1251,6261,399
English LiteratureAn Inspector Calls: Character Insights
Explore in-depth analysis and key quotes for characters in J.B. Priestley's 'An Inspector Calls'. This resource covers Gerald Croft, Inspector Goole, Sheila Birling, Mrs. Birling, Eric Birling, and Eva Smith, focusing on themes of class, gender roles, and social responsibility. Ideal for students aiming for Grade 8 and above.
1025,403907
CriminologyWJEC Unit 4 Criminology
Criminology unit 4 detailed revision note
127,142124
C
BiologyCell Biology and Cell structure
cell structures
93,1650
CriminologyCriminology Theories Overview
Explore key criminology theories and their implications on crime and deviance. This comprehensive summary covers biological, psychological, and sociological perspectives, including labelling theory, right realism, and the impact of social campaigns on policy development. Ideal for A-Level criminology students seeking to understand the complexities of criminal behaviour and the factors influencing crime prevention strategies.
129,753210
English LiteratureRomeo and Juliet: Key themes
Key Romeo and Juliet themes and analysed quotes
106,695198
Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.6/5App Store
4.7/5Google 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 SiOS 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 KlichAndroid 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.
AnnaiOS user