Coral reefs are amazing underwater ecosystems that face many threats... Show more
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Nov 23, 2025
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Coral reefs are amazing underwater ecosystems that face many threats... Show more










Coral reefs are like underwater cities where different organisms depend on each other to survive. When something disrupts this balance, the whole ecosystem can change dramatically!
Looking at the coral reef simulation, we can see how fishing impacts the reef. When net fishing increases to 50%, fish populations decline, but plant life grows because there aren't as many fish eating it. This shows how removing one organism affects others.
Biotic factors (living parts of an ecosystem) like bacteria, humans, and invasive species can cause major changes to reefs. For example, when fish populations decrease, creatures like sponges, algae, and sea urchins might increase because there are fewer predators eating them.
Science Connection: Invasive species like the Burmese python in Florida cause ecosystem imbalances because native species haven't evolved defenses against these newcomers. Similarly, coral reefs face threats from non-native species that can disrupt their delicate balance.

Reef fish have specific roles in keeping the ecosystem balanced. Each fish has its own important job! Parrotfish eat algae, angelfish feed on sponges, snappers hunt young fish and small creatures, while groupers feed on other fish.
When we remove too many of one fish species, it creates a domino effect. For example, when grouper fishing increases to 70%, snapper populations rise while parrotfish and angelfish slightly decrease. This happens because fewer groupers means fewer predators hunting the snappers.
With heavy net fishing (which affects all fish equally), the reef changes dramatically. At 20% net fishing, populations can eventually recover. But at higher levels (60%-80%), fish populations crash, causing algae to increase and corals to suffer.
Fun Fact: Reef ecosystems can handle some fishing, but they need time to recover! Scientists study these relationships to create fishing rules that help people while protecting reefs.

Corals can get sick too! Black band disease and white band disease are two major threats to coral reefs. When these diseases spread, they can wipe out entire coral species.
In the simulation, when black band infection rate hits 100%, Boulder Star Coral quickly disappears. Interestingly, Staghorn Coral increases because it now has more space to grow! When white band disease strikes, the opposite happens - Staghorn Coral dies off while Boulder Star Coral thrives.
Stressed corals catch diseases more easily. When ocean conditions aren't ideal (high temperatures, low pH, or too many nutrients from agriculture), corals become weakened and disease spreads faster. This is like how you're more likely to catch a cold when you're already tired and stressed!
Critical Thinking: Coral diseases might seem like natural events, but human activities often make corals more vulnerable by stressing them before disease even arrives.

Imagine a new kid moves to your school and starts taking everyone's lunch money! That's similar to what happens when invasive species enter reef ecosystems - they disrupt everything!
The red lionfish is a perfect example. Native to the Pacific Ocean, it has now spread throughout the Caribbean. With venomous spines that protect it from predators and a huge appetite for smaller fish, lionfish can quickly reduce fish diversity. In the simulation, fish species dropped from 294 to just 176 after 20 years of lionfish invasion!
Things get even worse when multiple problems hit reefs simultaneously. When sea urchins die from disease AND lionfish invade, the reef collapses - only algae and sea turtles survive! Similarly, the crown-of-thorns starfish (another Pacific native) could devastate Caribbean reefs if it ever invades because it eats corals directly.
Take Action: Knowing about these threats helps scientists develop ways to protect reefs. Some places even encourage divers to hunt and eat lionfish to control their population!





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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
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
Coral reefs are amazing underwater ecosystems that face many threats from both natural and human-made factors. In this exploration, we'll dive into how different "biotic factors" (living things) impact coral reef health. You'll discover how fishing, disease, and invasive species... Show more

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Coral reefs are like underwater cities where different organisms depend on each other to survive. When something disrupts this balance, the whole ecosystem can change dramatically!
Looking at the coral reef simulation, we can see how fishing impacts the reef. When net fishing increases to 50%, fish populations decline, but plant life grows because there aren't as many fish eating it. This shows how removing one organism affects others.
Biotic factors (living parts of an ecosystem) like bacteria, humans, and invasive species can cause major changes to reefs. For example, when fish populations decrease, creatures like sponges, algae, and sea urchins might increase because there are fewer predators eating them.
Science Connection: Invasive species like the Burmese python in Florida cause ecosystem imbalances because native species haven't evolved defenses against these newcomers. Similarly, coral reefs face threats from non-native species that can disrupt their delicate balance.

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Improve your grades
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Reef fish have specific roles in keeping the ecosystem balanced. Each fish has its own important job! Parrotfish eat algae, angelfish feed on sponges, snappers hunt young fish and small creatures, while groupers feed on other fish.
When we remove too many of one fish species, it creates a domino effect. For example, when grouper fishing increases to 70%, snapper populations rise while parrotfish and angelfish slightly decrease. This happens because fewer groupers means fewer predators hunting the snappers.
With heavy net fishing (which affects all fish equally), the reef changes dramatically. At 20% net fishing, populations can eventually recover. But at higher levels (60%-80%), fish populations crash, causing algae to increase and corals to suffer.
Fun Fact: Reef ecosystems can handle some fishing, but they need time to recover! Scientists study these relationships to create fishing rules that help people while protecting reefs.

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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Corals can get sick too! Black band disease and white band disease are two major threats to coral reefs. When these diseases spread, they can wipe out entire coral species.
In the simulation, when black band infection rate hits 100%, Boulder Star Coral quickly disappears. Interestingly, Staghorn Coral increases because it now has more space to grow! When white band disease strikes, the opposite happens - Staghorn Coral dies off while Boulder Star Coral thrives.
Stressed corals catch diseases more easily. When ocean conditions aren't ideal (high temperatures, low pH, or too many nutrients from agriculture), corals become weakened and disease spreads faster. This is like how you're more likely to catch a cold when you're already tired and stressed!
Critical Thinking: Coral diseases might seem like natural events, but human activities often make corals more vulnerable by stressing them before disease even arrives.

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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Imagine a new kid moves to your school and starts taking everyone's lunch money! That's similar to what happens when invasive species enter reef ecosystems - they disrupt everything!
The red lionfish is a perfect example. Native to the Pacific Ocean, it has now spread throughout the Caribbean. With venomous spines that protect it from predators and a huge appetite for smaller fish, lionfish can quickly reduce fish diversity. In the simulation, fish species dropped from 294 to just 176 after 20 years of lionfish invasion!
Things get even worse when multiple problems hit reefs simultaneously. When sea urchins die from disease AND lionfish invade, the reef collapses - only algae and sea turtles survive! Similarly, the crown-of-thorns starfish (another Pacific native) could devastate Caribbean reefs if it ever invades because it eats corals directly.
Take Action: Knowing about these threats helps scientists develop ways to protect reefs. Some places even encourage divers to hunt and eat lionfish to control their population!

Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy

Access to all documents
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By signing up you accept Terms of Service and Privacy Policy

Access to all documents
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Join milions of students
By signing up you accept Terms of Service and Privacy Policy

Access to all documents
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By signing up you accept Terms of Service and Privacy Policy

Access to all documents
Improve your grades
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By signing up you accept Terms of Service and Privacy Policy
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.
You can download the app in the Google Play Store and in the Apple App Store.
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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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