I feel like a good place to start is with an investigation to understand why sexual reproduction is better than asexual reproduction. On the surface asexual reproduction seems to have a lot more positive attributes than sexual reproduction. Organisms that reproduce asexually pass on a duplicate of their genetic material, and don't have to worry about the random outcome of allele frequencies from crossing over. Asexual reproduction occurs more quickly because the organism doesn't have to find a mate to reproduce. So asexual organisms don't have to worry about impressing anybody. All of these qualities that asexual reproducers possess are great if the environment they live in is unchanging. But what happens if the environment decides to change like it inevitably does. Well if the asexual reproducers aren't fit for the environment they die and so will the rest of their offspring because they inherited the exact same disabilities that the parent organism had.
This is one of the instances that sexual reproduction really comes in handy. If the parent of seven offspring dies because they was not adapt for the changes that occurred in the environment then the offspring still have a chance for survival if they inherited a trait from the other parent that would help them survive in the changing environment. Another reason why sexual reproduction is so beneficial is that it is better at combating disease. If a parent has a disease like Huntington's disease and that person reproduces with someone who doesn't have the disease there is a chance that when they reproduce the child will not have the disease. If a person reproduced asexually then if they had Huntington's disease then they would continually pass that on from generation to generation.
Link of original site of video
Caitlin,
ReplyDeleteThis is certainly a great (and logical) start. The wording at the beginning of the second paragraph is a bit hard to follow, but the content is fine. The Red Queen", which was mentioned on the PBS site you hyperlinked, is a good book to consider as you proceed. I look forward to seeing the next post!
-Dr. Walker
Yes, not bad. But I was actually looking for some thing more in depth.
ReplyDeleteThis comment has been removed by the author.
ReplyDeleteAns.....Sexual mode of reproduction is better than asexual mode. Becz it involves the fusion of the male & female gamate to produce variants which are not identical to their parents & to themselves. It leads to variation which favours adaptations & finally survival of the species.
ReplyDeleteHaha asexaual organisms do not have to worry about impressing other organisms that was cool
ReplyDeleteHaha asexaual organisms do not have to worry about impressing other organisms that was cool
ReplyDeleteThe creation of two new cells from one involves copying of the DNA as well as of the cellular apparatus. The DNA copying mechanism, as we have noted, cannot be absolutely accurate, and the resultant errors are a source of variations in populations of organisms. Every individual organism cannot be protected by variations, but in a population, variations are useful for ensuring the survival of the species. It would therefore make sense if organisms came up with reproductive modes that allowed more and more variation to be generated. While DNA-copying mechanisms are not absolutely accurate, they are precise enough to make the generation of variation a fairly slow process. If the DNA copying mechanisms were to be less accurate, many of the resultant DNA copies would not be able to work with the cellular apparatus, and would die. So how can the process of making variants be speeded up? Each new variation is made in a DNA copy that already has variations accumulated from previous generations. Thus, two different individuals in a population would have quite different patterns of accumulated variations. Since all of these variations are in living individuals, it is assured that they do not have any really bad effects. Combining variations from two or more individuals would thus create new combinations of variants. Each combination would be novel, since it would involve two different individuals. The sexual mode ofreproduction incorporates such a process of combining DNA from two different individuals during reproduction. But this creates a major difficulty. If each new generation is to be the combination of the DNA copies from two pre-existing individuals, then each new generation will end up having twice the amount of DNA that the previous generation had. This is likely to mess up the control of the cellular apparatus by the DNA. Besides, if each generation doubles its DNA, fairly soon there will be only DNA on earth, with no room for anything else. How many ways can we think of for solving this difficulty? We have seen earlier that as organisms become more complex, the specialisation of tissue increases. One solution that many multi-cellular organisms have found for the problem mentioned above is to have special lineages of cells in specialised organs which have only half the number of chromosomes and half the amount of DNA as compared to the nonreproductive body cells. Thus, when these germ-cells from two individuals combine during sexual reproduction to form a new individual, it results in re-establishment of the number of chromosomes and the DNA content in the new generation. If the zygote is to grow and develop into an organism which has highly specialised tissues and organs, then it has to have sufficient stores of energy for doing this. In very simple organisms, it is seen that the two germ-cells are not very different from one another, or may even be similar. But as the body designs become more complex, the germ-cells also specialise. One germ-cell is large and contains the food-stores while the other is smaller and likely to be motile. Conventionally, the motile germcell is called the male gamete and the germ-cell containing the stored food is called the female gamete. We shall see in the next few sections how the need to create these two different types of gametes give rise to differences in the male and female reproductive organs and, in some cases, differences in the bodies of the male and female organisms.
ReplyDeleteAryan Raj, unfortunate that u just copied from ncert text. Violation of copyright Act. You may be booked for it.
Deletei want something in more depth
ReplyDeleteIts so amazing i thinks
ReplyDeleteIts so amazing i thinks
ReplyDeletePersonally, it's quite useful esp for my Bio
ReplyDeleteI am bold enough among many others to state that there is now a potent cure to this sickness but many are unaware of it. I discovered that I was infected with the virus 3 months ago, after a medical check-up. My doctor told me and I was shocked, confused and felt like my world has crumbled. I was dying slowly due to the announcement of my medical practitioner but he assured me that I could leave a normal life if I took my medications (as there was no medically known cure to Herpes). I went from churches to churches but soon found that my case needed urgent attention as I was growing lean due to fear of dying anytime soon. In a bid to look for a lasting solution to my predicament, I sought for solutions from the herbal world. I went online and searched for every powerful trado-medical practitioner that I could severe, cos I heard that the African Herbs had a cure to the Herpes syndrome. It was after a little time searching the web that I came across one Dr Itua(A powerful African Herbal Doctor), who offered to help me at a monetary fee. I had to comply as this was my final bus-stop to receiving a perfect healing. My last resolve was to take my life by myself, should this plan fail. At last it worked out well. He gave me some steps to follow and I meticulously carried out all his instructions. Last month, to be precise, I went back to the hospital to conduct another test and to my amazement, the results showed that negative,Dr Itua Can As Well Cure The Following Desease…Cancer,Hiv,Herpes, Hepatitis B,Liver Inflammatory,Diabetis,Fribroid, Dercum,fibromyalgia,Get Your Ex Back,Als,SYPHILLIS,Genetic disease,Epilepsy, Parkinson's disease.Fibrodysplasia Ossificans Progressiva.You can free yourself of this Herpes virus by consulting this great African Herbal Doctor via this e-mail: drituaherbalcenter@gmail.com or call and whatsapp him on +2348149277967 He will help you and his herb medication is sure. he has the cure on all disease .You can talk to me on INSTAGRAM..tashamoore219....
ReplyDeletebruh
ReplyDeletestop copying thing from the internet use your head
ReplyDelete