Overview of Animals - 1

by Jason Amores Sumpter
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Hi. In this video we'll be going through a general introduction to animals and in later videos will explore more specifics. So animals are multi cellular header trophic. You carry outs and we feed by ingesting our food, meaning we actually pull our food into our bodies to absorb the nutrients. Now most animals are deployed and produce gametes directly by my Asus, which is different if you'll recall than how. For example, plants do it Where, um spores air actually produced by my Asus and their gametes are often produced by mitosis. Animals lack cell walls, right plants you cellulose fungi use kitten. We don't have that. Instead, we use an extra cellular matrix for support. All animals are motel, at least at some point in every animal's life. They exhibit active movement, right? Intentional active movement. Now most animals reproduce sexually, though there are some that reproduce a sexually. But for the most part, we're going to focus on, uh, what you could think of as more common animals. Now, animals also undergo embryonic development, and this is when the zygote is undergoing cleavage. And you actually, uh, we'll see more or less three patterns of birth for animals. So you have vivid Paris, which in which the embryo will actually be nourished inside the parent and the parent will give birth to live offspring. This is in contrast to you over Paris organisms, in which the parent actually lays eggs and the embryo is actually nourished by yolk in the egg, as opposed to the parent directly and in ovo Viva Paris organisms. The eggs actually will remain inside the parent until they're ready to hatch. But the embryo is still nourished by the yoke, not directly by the parents, so humans and mammals in general, are vivid Paris organisms. As you might have guessed. Now it's worth noting that during embryonic development, animals actually have a lot of similarities here. In this image, you can see the embryonic development of a fish, salamander, tortoise, chick, calf and human, and look at the similarities early on and development. As development goes on, organisms become more and more different, but early on their striking similarities. And that is because even though animals have a wide variety of different body plans and morphology ease, the genes that control the development of the body are common toe. Almost all animals and they're called Homo box jeans. And if you want to learn more about these, check out the videos on animal development. Now. Animals also have tissues, and tissues are basically organized groups of similar cells that act as a functionally unit. Nice example of a tissue. It's this right here. This is muscle tissue. Notice the what are called striations. Basically, they're sort of a line pattern to the tissue, and that has to do with the various filaments. The contract I'll filaments that allow muscle thio contract. Um, we'll learn more about that in the chapter on muscles. But for now, the important thing to take away is that all of these individual muscle cells work together is a functional unit. Thio make up this muscle tissue. Now, many tissues will actually, um, be incorporated into organs, which also act as a functional unit and are another example of how tissues can be used. The other thing that's kind of special about animals is that we have a nervous system now. Not every animal has a nervous system, but many animals have nervous systems, especially uh, animals that you might think are less complex or not complex enough to have a nervous system like a worm or a jellyfish, for example, and let me jump out of the picture here for a second. As you can see, this is a worm, and this worm, believe it or not, has a brain right there. And it has a nervous system that you can see being depicted here and here. It's this dark portion here on the bottom. We're looking, getting a top down look and here or getting a side view of the organisms. Nervous system. So those were some general features shared by animals. Let's flip the page and talk about some more specific features of animals.