Ryby jsou fascinující vodní tvorové, kteří obývají naši planetu už... Show more
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Updated Mar 31, 2026
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Ryby: Popis, Způsob Života a Zajímavosti
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Ryby - základní charakteristika a životní prostředí
Představ si, že bys musel celý život strávit pod vodou - přesně to dělají ryby! Tyto úžasné vodní živočichy žijí výhradně ve vodním prostředí a dokázaly se na něj dokonale přizpůsobit.
Nejdůležitější vlastností ryb je jejich dýchání pomocí žaber. Zatímco my potřebujeme kyslík ze vzduchu, ryby si dokáží vzít kyslík přímo z vody díky svým žábrám. Je to jako mít speciální filtr, který z vody vytáhne to, co ryba potřebuje k životu.
Ryby jsou ektotermní (studenokrevné), což znamená, že nemají vlastní "topení" jako my. Jejich tělesná teplota závisí na tom, jak studená nebo teplá je voda kolem nich.
Tip na zkoušku: Zapamatuj si, že ryby jsou nejstarší i nejpočetnější skupina obratlovců - tuhle informaci učitelé milují!
Potrava, pohyb a rozmnožování ryb
Stravování ryb je stejně pestré jako jejich druhy. Někteří jedí drobný plankton (takové malé "polévkové" organismy), jiní loví větší kořist nebo si pochutnávají na řasách a vodních rostlinách. Každý druh si našel svou specialitu!
Pohyb ryb funguje podobně jako u lodí. Ocasní ploutev je jejich "motor" pro pohyb vpřed, zatímco prsní a břišní ploutve slouží jako kormidla pro změnu směru. Některé odvážné druhy se dokonce naučily létat nebo šplhat - ryby prostě umí překvapit!
Většina ryb se rozmnožuje kladením vajíček, ale pak často své potomky nechají napospas osudu. Jen některé zodpovědné druhy hlídají svá vajíčka před predátory nebo dokonce rodí živá mláďata.
Zajímavost: Ryby existují na Zemi už více než 500 milionů let - to je mnohem déle než dinosauři!
Zajímavosti a fakta o rybách
Se svými více než 32 500 druhy jsou ryby skutečnými rekordmany mezi obratlovci. To znamená, že každý den by ses mohl učit o novém druhu ryby a stále by ti to trvalo skoro sto let!
Jejich ektotermní povaha jim dává velkou výhodu - nepotřebují tolik energie na udržování tělesné teploty jako my. Proto dokáží přežít i s menším množstvím potravy a přizpůsobit se různým teplotním podmínkám.
Fakt, že jsou nejstaršími obratlovci na planetě, znamená, že měly obrovské množství času na to, aby se přizpůsobily všem možným podmínkám. Proto je dnes najdeš v ledových vodách i v tropických mořích, v hlubokých oceánech i v mělkých potůčcích.
Pro lepší zapamatování: Ryby = voda + žábry + ploutve + vajíčka. Tuhle jednoduchou rovnici už nezapomeneš!
We thought you’d never ask...
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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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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 Knowunity AI. 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 Knowunity AI. 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
Ryby: Popis, Způsob Života a Zajímavosti
Ryby jsou fascinující vodní tvorové, kteří obývají naši planetu už víc než 500 milionů let! Jsou to nejstarší obratlovci na Zemi a zároveň jejich nejpočetnější skupina s úžasnými 32 500 různými druhy.
Ryby - základní charakteristika a životní prostředí
Představ si, že bys musel celý život strávit pod vodou - přesně to dělají ryby! Tyto úžasné vodní živočichy žijí výhradně ve vodním prostředí a dokázaly se na něj dokonale přizpůsobit.
Nejdůležitější vlastností ryb je jejich dýchání pomocí žaber. Zatímco my potřebujeme kyslík ze vzduchu, ryby si dokáží vzít kyslík přímo z vody díky svým žábrám. Je to jako mít speciální filtr, který z vody vytáhne to, co ryba potřebuje k životu.
Ryby jsou ektotermní (studenokrevné), což znamená, že nemají vlastní "topení" jako my. Jejich tělesná teplota závisí na tom, jak studená nebo teplá je voda kolem nich.
Tip na zkoušku: Zapamatuj si, že ryby jsou nejstarší i nejpočetnější skupina obratlovců - tuhle informaci učitelé milují!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Potrava, pohyb a rozmnožování ryb
Stravování ryb je stejně pestré jako jejich druhy. Někteří jedí drobný plankton (takové malé "polévkové" organismy), jiní loví větší kořist nebo si pochutnávají na řasách a vodních rostlinách. Každý druh si našel svou specialitu!
Pohyb ryb funguje podobně jako u lodí. Ocasní ploutev je jejich "motor" pro pohyb vpřed, zatímco prsní a břišní ploutve slouží jako kormidla pro změnu směru. Některé odvážné druhy se dokonce naučily létat nebo šplhat - ryby prostě umí překvapit!
Většina ryb se rozmnožuje kladením vajíček, ale pak často své potomky nechají napospas osudu. Jen některé zodpovědné druhy hlídají svá vajíčka před predátory nebo dokonce rodí živá mláďata.
Zajímavost: Ryby existují na Zemi už více než 500 milionů let - to je mnohem déle než dinosauři!
Sign up to see the contentIt's free!
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Improve your grades
Join milions of students
Zajímavosti a fakta o rybách
Se svými více než 32 500 druhy jsou ryby skutečnými rekordmany mezi obratlovci. To znamená, že každý den by ses mohl učit o novém druhu ryby a stále by ti to trvalo skoro sto let!
Jejich ektotermní povaha jim dává velkou výhodu - nepotřebují tolik energie na udržování tělesné teploty jako my. Proto dokáží přežít i s menším množstvím potravy a přizpůsobit se různým teplotním podmínkám.
Fakt, že jsou nejstaršími obratlovci na planetě, znamená, že měly obrovské množství času na to, aby se přizpůsobily všem možným podmínkám. Proto je dnes najdeš v ledových vodách i v tropických mořích, v hlubokých oceánech i v mělkých potůčcích.
Pro lepší zapamatování: Ryby = voda + žábry + ploutve + vajíčka. Tuhle jednoduchou rovnici už nezapomeneš!
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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4.6/5
App Store
4.7/5
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 Knowunity AI. 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 Knowunity AI. 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