Visit: http://academyofone.org Forum: http://www.academyofone.org/forums/ Youtube: https://www.youtube.com/user/Academyofone1 Article: http://www.academyofone.org/animalia-kingdoms-of-eukarya-introduction-to-biology-11-8/ Royalty free music licensed by http://www.stockmusic.net Royalty free photos licensed by http://www.bigstockphoto.com Script: Now I don’t know what the fox says or what the hamster dances to... but we do know that the fox and the hamster is within the domain of eukaryota. What’s more, I know that a hamster is part of the kingdom Animalia. What’s going on everybody! My name is Jack Jenkins and this is Academy of One. Today we are talking about kingdoms of eukaryota: Animalia. The kingdom of Animalia or animals for short is a vast and exciting kingdom. This kingdom includes penguins, giraffes, crocodiles, humans and apes. Now that’s just a sample off this kingdom and you still see a lot of variance between the species. With all this diversity it’s hard to tell what an animal is vs a non-animal eukaryota. So we can’t judge solely on the looks. To combat this problem we use cellular, anatomical and behavior differences. Animals have a few distinct features that fungi, protists and plants don’t have. First, all animals are multicellular. If it’s unicellular then it belongs in one of the other kingdoms or other domains. Second animal cells don’t have a cell wall. They rely just on their cell membrane. The third main characteristic of animals is that animals don’t have chloroplast. Because of the lack of chloroplast animals must eat different organisms to survive. Some animals are herbivores who just eat plants. Others are carnivores who just eat meat. Most animals are omnivores, they eat both plants and animals. We humans are naturally omnivores unless you are vegetarian or meatitarian. Man I love bacon. The last main characteristic of animals is the fact that they are able to respond rapidly to stimuli. This is because animals have developed nerve cells and muscle tissue. When looking at our evolutionary history you can easily see multicellular fossils such as Grypania spiralis or the bones of the dinosaurs. The early animals however, didn’t leave much of an imprint. While there are a ton of fossils from the early days of earth that prove animals were around... they are rather scattered. So instead of using animal fossils to tell the evolutionary history, scientist decided to use DNA sequences and anatomical features instead. Animals came from the first prokaryotic and then evolved from protists. Then the protists evolved to eventually form animals. This leads us to one of the first major split in our evolutionary tree. This split is animals gained various tissue. Tissue in this sense means a group of cells made up of specialized cells and there product. An example is muscle tissue. Almost all animals have this except for the lonely sponge. The sponge has a bunch of non-specialized cells working pretty much on their own. This gives evidence that we split from the sponge rather early in our evolutionary tree. This also gives evidence that the earliest of animals were all aqueous animals. So we may not have fossils but we can still see a very distinct evolutionary line. With the adaptation of tissue, animals started taking a more defiant shape. With this shape came another characteristic of animals called body symmetry. An animal is said to be symmetrical if at least one plane is equal to the other as long as that plane is split down the middle. For example, here is an eight. If we split it down the middle and remove one half then it will still look the same once we put it next to a mirror. There are two different types of symmetry that animals can be. They can be radical symmetrical or bilateral symmetrical. Radial symmetry is symmetry that exist with any plane. An example of a radical symmetrical animal is a sea urchin. If you cut a sea urchin four different ways you see that the left side is just like the right and the top part is just like the bottom. Bilateral symmetry is symmetry with only one plane through the center. An example of this is with an ant. If you cut an ant down the middle then it’s symmetrical. If you do it through the middle then the ant is not symmetrical. Radical and bilateral symmetry is important because it tells us the number of germ layers an animal will have when it’s in the embryonic stage. Radical animals have two germ layers while bilateral animals have three. The number of germ layers are important because they turn into the organs during the formation of birth. On the anatomy and physiology course I have a video on organogenesis which will show you more information.

• published: 22 Jul 2015
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