Subjects
Biology
Chemistry
AP Chemistry
English
AP English Literature
140
•
Dec 9, 2025
•
Sarah
@sarah.knowunity
Animals evolved from single-celled organisms into the incredible diversity we... Show more
Animals evolved from colony-forming protists called choanoflagellates. All animals (Metazoa) are multicellular heterotrophs with specialized cells and structural proteins like collagen. The simplest animals, sponges (Porifera), lack true tissues but have specialized cells like choanocytes for feeding.
True tissues appear in Eumetazoa, which includes jellyfish and hydras (Cnidarians) with their radial symmetry and gastrovascular cavity. Most animals belong to Bilateria, featuring bilateral symmetry and three tissue layers (triploblastic). Bilateral symmetry enabled the development of a distinct head (cephalization) and directional movement.
The Lophotrochozoa group includes flatworms, rotifers, annelids (segmented worms), and molluscs. Flatworms are acoelomates (lacking a body cavity), while annelids and molluscs are coelomates (having a true body cavity). Annelids like earthworms show segmentation, while molluscs include gastropods (snails), bivalves (clams), and cephalopods (octopus, squid).
Did you know? The development of a true body cavity (coelom) was a revolutionary advancement in animal evolution. It allowed for more efficient organ systems and movement, setting the stage for more complex body plans!
Ecdysozoa represents the most diverse animal group on Earth, including nematodes (roundworms) and arthropods. Arthropods, characterized by jointed appendages and hard exoskeletons of chitin, exploded in diversity during the Cambrian Period. The evolution of the Hox gene complex revolutionized body organization by controlling where and how body parts develop.
Arthropods include chelicerates (spiders, scorpions), myriapods (centipedes, millipedes), hexapods (insects), and crustaceans. Each group shows specialized adaptations - from the chelicerae (feeding appendages) of spiders to the three-part body and metamorphosis of insects. These modifications helped arthropods conquer nearly every habitat on Earth.
Deuterostomes include echinoderms and chordates, distinguished by their embryonic development. Echinoderms (sea stars, urchins) have water vascular systems and calcareous plates. Chordates, our own phylum, feature pharyngeal slits, a notochord, a hollow dorsal nerve cord, and a post-anal tail during development.
Think about this! The same Hox genes that organize body parts in a simple lancelet also organize yours. This genetic conservation across such different animals reveals our deep evolutionary connections!
Vertebrates evolved from simple chordates, developing first a cranium (skull), then vertebrae, jaws (gnathostomes), and finally bony skeletons (osteichthyans). These developments set the stage for the invasion of land and the evolution of tetrapods.
Tetrapods evolved from lobe-finned fish when fins transformed into limbs with digits. This revolutionary adaptation allowed vertebrates to conquer land. The evolution of the amniotic egg—with protective membranes for the embryo—further freed animals from returning to water for reproduction.
Amphibians straddle aquatic and terrestrial worlds, undergoing metamorphosis from aquatic tadpoles to land-dwelling adults. Reptiles fully adapted to land with waterproof scales, internal fertilization, and eggs laid on land. Birds evolved from reptilian ancestors (specifically dinosaurs), developing feathers, lightweight skeletons, and endothermy for the demands of flight.
Mammals introduced revolutionary features: mammary glands, hair, endothermy, four-chambered hearts, and large brains. They diversified into three main groups: egg-laying monotremes (platypus), pouched marsupials (kangaroos), and placental mammals (including humans). The placenta allowed longer embryonic development and more complex offspring.
Amazing fact: Human and chimpanzee genomes are 96% identical! Those few percentage points of difference account for all our unique human traits.
Primates evolved specialized hands with opposable thumbs, large brains, and complex social behaviors. Humans (genus Homo) developed bipedalism, significantly larger brains, and complex language. Paleoanthropologists study ancient human remains like "Lucy" to understand our evolutionary journey, with modern humans appearing approximately 160,000 years ago.
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.
App Store
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
Sarah
@sarah.knowunity
Animals evolved from single-celled organisms into the incredible diversity we see today. This summary explores how scientists classify animals based on their body structures, development patterns, and evolutionary relationships, taking you on a journey from simple sponges to complex mammals... Show more
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Animals evolved from colony-forming protists called choanoflagellates. All animals (Metazoa) are multicellular heterotrophs with specialized cells and structural proteins like collagen. The simplest animals, sponges (Porifera), lack true tissues but have specialized cells like choanocytes for feeding.
True tissues appear in Eumetazoa, which includes jellyfish and hydras (Cnidarians) with their radial symmetry and gastrovascular cavity. Most animals belong to Bilateria, featuring bilateral symmetry and three tissue layers (triploblastic). Bilateral symmetry enabled the development of a distinct head (cephalization) and directional movement.
The Lophotrochozoa group includes flatworms, rotifers, annelids (segmented worms), and molluscs. Flatworms are acoelomates (lacking a body cavity), while annelids and molluscs are coelomates (having a true body cavity). Annelids like earthworms show segmentation, while molluscs include gastropods (snails), bivalves (clams), and cephalopods (octopus, squid).
Did you know? The development of a true body cavity (coelom) was a revolutionary advancement in animal evolution. It allowed for more efficient organ systems and movement, setting the stage for more complex body plans!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Ecdysozoa represents the most diverse animal group on Earth, including nematodes (roundworms) and arthropods. Arthropods, characterized by jointed appendages and hard exoskeletons of chitin, exploded in diversity during the Cambrian Period. The evolution of the Hox gene complex revolutionized body organization by controlling where and how body parts develop.
Arthropods include chelicerates (spiders, scorpions), myriapods (centipedes, millipedes), hexapods (insects), and crustaceans. Each group shows specialized adaptations - from the chelicerae (feeding appendages) of spiders to the three-part body and metamorphosis of insects. These modifications helped arthropods conquer nearly every habitat on Earth.
Deuterostomes include echinoderms and chordates, distinguished by their embryonic development. Echinoderms (sea stars, urchins) have water vascular systems and calcareous plates. Chordates, our own phylum, feature pharyngeal slits, a notochord, a hollow dorsal nerve cord, and a post-anal tail during development.
Think about this! The same Hox genes that organize body parts in a simple lancelet also organize yours. This genetic conservation across such different animals reveals our deep evolutionary connections!
Vertebrates evolved from simple chordates, developing first a cranium (skull), then vertebrae, jaws (gnathostomes), and finally bony skeletons (osteichthyans). These developments set the stage for the invasion of land and the evolution of tetrapods.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Tetrapods evolved from lobe-finned fish when fins transformed into limbs with digits. This revolutionary adaptation allowed vertebrates to conquer land. The evolution of the amniotic egg—with protective membranes for the embryo—further freed animals from returning to water for reproduction.
Amphibians straddle aquatic and terrestrial worlds, undergoing metamorphosis from aquatic tadpoles to land-dwelling adults. Reptiles fully adapted to land with waterproof scales, internal fertilization, and eggs laid on land. Birds evolved from reptilian ancestors (specifically dinosaurs), developing feathers, lightweight skeletons, and endothermy for the demands of flight.
Mammals introduced revolutionary features: mammary glands, hair, endothermy, four-chambered hearts, and large brains. They diversified into three main groups: egg-laying monotremes (platypus), pouched marsupials (kangaroos), and placental mammals (including humans). The placenta allowed longer embryonic development and more complex offspring.
Amazing fact: Human and chimpanzee genomes are 96% identical! Those few percentage points of difference account for all our unique human traits.
Primates evolved specialized hands with opposable thumbs, large brains, and complex social behaviors. Humans (genus Homo) developed bipedalism, significantly larger brains, and complex language. Paleoanthropologists study ancient human remains like "Lucy" to understand our evolutionary journey, with modern humans appearing approximately 160,000 years ago.
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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Explore the fundamentals of biological classification, including the Linnaean system and the five kingdoms of life. This summary covers key concepts such as species classification, the characteristics of each kingdom, and the significance of binomial nomenclature. Ideal for students studying biology and taxonomy.
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BiologyMaster the fundamental principles of biology with this comprehensive flashcard set designed specifically for grade 10 students. Explore key concepts and build a solid foundation for future studies in the field of biology.
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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
Algebra
Calculus 1
Algebra 1
Overige