Tipos de Reprodução e Desenvolvimento

#Biology #Reproduction #Zoology Lesson aimed at high school and ENEM (Brazilian National High School Exam) students about the different types of reproduction. Script below. Due to lack of space, it is not possible to include the video bibliography. If you would like it, please contact me and I will send it. Video script: All living organisms came from other living organisms. This phrase is very important for biology, although it is still debated in some spheres of science (TUMB Theories of the origin of life). But we can say with some confidence that every living organism has the ability to reproduce, or came from some reproduction. So in this lesson we will talk about the types of reproduction that exist and their developments. Starting with the reproductions that the organism can do on its own, the famous asexual reproductions, which the name itself says, since the prefix "a" in Latin is negative, non-sexual. (Try making a list of pros and cons, and as I speak, you add the information to the list.) The advantage of this type of reproduction is clear: you don't spend time and energy looking for partners; you simply reproduce on your own, making your reproduction much faster and more efficient. The problem is that this comes at a cost. Because there is no other organism helping with reproduction, genetic variation is very low, relying only on random mutations, which, in proportion to sexual reproduction, are almost negligible. It is generally done by small animals, protists, bacteria, and plants. You will rarely see large animals doing this type of reproduction, but I will talk about the types and give examples of them: Starting with budding or gemmiparity, which is the spontaneous appearance of a bud or gem in an organism, which, upon detaching from the main organism, will grow and become an independent organism. This type of reproduction generally occurs in plants, sponges, and cnidarians. Next, we have strobilation, where the organism fragments into two or more parts that will develop into complete animals again. This generally occurs in cnidarians, flatworms, and annelids. Another famous example is regeneration (Wonderland and Deadpool), which, unlike in cartoons, functions for reproduction. When the organism is cut by some external agent, it can use the detached and mutilated parts to form new organisms, as happens in cnidarians, sponges, and flatworms. It's important not to confuse this with tissue regeneration, which happens with geckos, for example, that regenerate their tails. In that case, cartoons might have a point, but this type of regeneration could be the subject of another video, as it is so complex. We can also have sporulation, which is the production of a spore by some organisms containing all of their genetic material. In this case, the spore remains dormant for a period until it finds a suitable environment to begin growing. When it finds one, it gives rise to a new organism. This type of reproduction is very common in bacteria, plants, and fungi. Another well-known example is binary fission, which only occurs at the cellular level, meaning it only happens in unicellular organisms. It's very similar to the mitosis process in multicellular organisms, with the difference that here two entire organisms are formed, and each one reconstructs its internal and external structures. It's very common in bacteria, archaea, and protists. Finally, we have parthenogenesis, where an ovum gives rise to a new organism without the presence of a male gamete; that is, only the mother's genetic material is present. This type of reproduction is common in insects and arachnids (bees and yellow scorpions). Now, if you think life is boring without two individuals to make a new individual, let's talk about sexually reproducing organisms. (Try to make a list of pros and cons, and as I speak, you add the information to the list.) Here, the advantages and disadvantages are simple: this type of reproduction is much more difficult because it requires the organism to find a partner, which involves a high energy expenditure. However, it guarantees a modification in the offspring's genetic makeup, since it is a mixture of both parents, ensuring the variability of the species, which is a very good thing. Therefore, we can say that it is a more difficult reproduction to perform, but with better results in terms of the genetic quality of the offspring. Thus, we can separate sexual organisms into two types: unisexual or dioecious organisms, which are those that have males and females in the species and need both to reproduce, or hermaphroditic or monoecious organisms, where organisms can be male and female, that is, all can reproduce with all. Regardless of whether they are monoecious or dioecious, once they meet, they need to go through the process of gamete union, the famous fertilization.