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Ummi
14/12/2025
Biology
The Concept of Heredity
68
•
14 Dec 2025
•
Understanding Heredity: Basics and Concepts
Ummi
@ummi_.com
1 / 5
The Basics of Heredity
Think of heredity as nature's copying system - it's how characteristics get passed down through generations. Your parents didn't randomly give you traits; there's actually a precise biological mechanism at work.
Genes are like tiny instruction manuals stored in your cells, each one controlling specific traits like eye colour or blood type. These genes live on chromosomes - think of them as filing cabinets in your cell's nucleus that keep all your genetic information organised.
Here's where it gets interesting: genes come in different versions called alleles. It's like having different flavours of the same recipe - you might inherit a brown-eye allele from your mum and a blue-eye allele from your dad.
Quick Tip: Your genotype is your actual genetic code (what's written in your DNA), whilst your phenotype is what you can actually see (like having brown eyes).
Understanding Genetic Expression
Not all alleles are created equal - some are bossy and others are more passive! Dominant alleles are the controlling ones that mask recessive alleles. For example, if you inherit a dominant brown-eye allele and a recessive blue-eye allele, you'll have brown eyes.
When you have two identical alleles for a trait, you're homozygous . If you've got two different alleles, you're heterozygous (one brown, one blue). This combination determines what traits actually show up.
Gregor Mendel, often called the "father of genetics," figured this all out by studying pea plants in his garden. His work in the 1800s laid the groundwork for everything we know about inheritance today.
Remember: Being heterozygous doesn't mean you're "half and half" - usually one allele will dominate and determine your visible trait.
Mendel's Laws and Inheritance Patterns
Mendel discovered two fundamental rules that govern how traits pass from parents to offspring. The Law of Segregation explains that you inherit one allele from each parent, and these separate when you eventually have children of your own.
The Law of Independent Assortment is equally important - it means that inheriting your dad's nose doesn't affect whether you'll get your mum's hair colour. Traits are inherited independently of each other.
Autosomal inheritance involves traits controlled by genes on regular chromosomes (not the X and Y sex chromosomes). Most of your characteristics follow this pattern. However, sex-linked inheritance affects traits on the X and Y chromosomes, which is why colour blindness is more common in males.
Key Point: These laws explain why siblings can look quite different despite having the same parents - it's all about which combination of alleles they inherit.
Beyond Simple Inheritance
Not all inheritance follows Mendel's straightforward dominant-recessive pattern - genetics can be more complex and interesting! Incomplete dominance creates a blended effect, like when red and white flowers produce pink offspring.
Codominance is different - both alleles express themselves fully. Human ABO blood types are a perfect example, where type AB blood shows both A and B characteristics equally.
Some traits are controlled by multiple alleles (more than two versions of a gene exist in the population) or involve polygenic inheritance, where several genes work together. Your height, skin colour, and intelligence all result from multiple genes collaborating.
Real-World Connection: Understanding these patterns helps explain why some genetic disorders skip generations or why certain traits seem to "run in families" in unexpected ways.
Genetic Variation and Modern Applications
Genetic variation keeps populations healthy and adaptable. Mutations introduce new alleles (though most are harmless), whilst recombination during reproduction shuffles existing genes into new combinations. Gene flow between populations and genetic drift also contribute to genetic diversity.
Modern genetics has incredible practical applications. In medicine, genetic testing helps diagnose hereditary conditions and develop personalised treatments. Agricultural scientists create crops that resist diseases or produce better yields.
Forensic science uses DNA profiling to solve crimes and identify victims. Even paternity testing relies on these same genetic principles you're learning about.
Future Focus: As genetic technologies advance, understanding these basics becomes increasingly important for making informed decisions about your health and family planning.
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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
Understanding Heredity: Basics and Concepts
Ummi
@ummi_.com
Ever wondered why you have your mum's eyes or your dad's height? Heredityis the fascinating process that passes traits from parents to children, and understanding it helps explain everything from your appearance to certain health conditions. This is the... Show more
The Basics of Heredity
Think of heredity as nature's copying system - it's how characteristics get passed down through generations. Your parents didn't randomly give you traits; there's actually a precise biological mechanism at work.
Genes are like tiny instruction manuals stored in your cells, each one controlling specific traits like eye colour or blood type. These genes live on chromosomes - think of them as filing cabinets in your cell's nucleus that keep all your genetic information organised.
Here's where it gets interesting: genes come in different versions called alleles. It's like having different flavours of the same recipe - you might inherit a brown-eye allele from your mum and a blue-eye allele from your dad.
Quick Tip: Your genotype is your actual genetic code (what's written in your DNA), whilst your phenotype is what you can actually see (like having brown eyes).
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Understanding Genetic Expression
Not all alleles are created equal - some are bossy and others are more passive! Dominant alleles are the controlling ones that mask recessive alleles. For example, if you inherit a dominant brown-eye allele and a recessive blue-eye allele, you'll have brown eyes.
When you have two identical alleles for a trait, you're homozygous . If you've got two different alleles, you're heterozygous (one brown, one blue). This combination determines what traits actually show up.
Gregor Mendel, often called the "father of genetics," figured this all out by studying pea plants in his garden. His work in the 1800s laid the groundwork for everything we know about inheritance today.
Remember: Being heterozygous doesn't mean you're "half and half" - usually one allele will dominate and determine your visible trait.
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
Mendel's Laws and Inheritance Patterns
Mendel discovered two fundamental rules that govern how traits pass from parents to offspring. The Law of Segregation explains that you inherit one allele from each parent, and these separate when you eventually have children of your own.
The Law of Independent Assortment is equally important - it means that inheriting your dad's nose doesn't affect whether you'll get your mum's hair colour. Traits are inherited independently of each other.
Autosomal inheritance involves traits controlled by genes on regular chromosomes (not the X and Y sex chromosomes). Most of your characteristics follow this pattern. However, sex-linked inheritance affects traits on the X and Y chromosomes, which is why colour blindness is more common in males.
Key Point: These laws explain why siblings can look quite different despite having the same parents - it's all about which combination of alleles they inherit.
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Beyond Simple Inheritance
Not all inheritance follows Mendel's straightforward dominant-recessive pattern - genetics can be more complex and interesting! Incomplete dominance creates a blended effect, like when red and white flowers produce pink offspring.
Codominance is different - both alleles express themselves fully. Human ABO blood types are a perfect example, where type AB blood shows both A and B characteristics equally.
Some traits are controlled by multiple alleles (more than two versions of a gene exist in the population) or involve polygenic inheritance, where several genes work together. Your height, skin colour, and intelligence all result from multiple genes collaborating.
Real-World Connection: Understanding these patterns helps explain why some genetic disorders skip generations or why certain traits seem to "run in families" in unexpected ways.
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
Genetic Variation and Modern Applications
Genetic variation keeps populations healthy and adaptable. Mutations introduce new alleles (though most are harmless), whilst recombination during reproduction shuffles existing genes into new combinations. Gene flow between populations and genetic drift also contribute to genetic diversity.
Modern genetics has incredible practical applications. In medicine, genetic testing helps diagnose hereditary conditions and develop personalised treatments. Agricultural scientists create crops that resist diseases or produce better yields.
Forensic science uses DNA profiling to solve crimes and identify victims. Even paternity testing relies on these same genetic principles you're learning about.
Future Focus: As genetic technologies advance, understanding these basics becomes increasingly important for making informed decisions about your health and family planning.
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.
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Most popular content in Biology
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English - inspector calls quotes and analysis
Quotes from every main character
English Literature10
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
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