BIOL 112 1nd Edition Exam 1 Study Guide Chapters 1 2 of the Red Queen 1 What are some of the costs of sexual reproduction In the Red Queen which is what Manson bases this particular semester off of it describes the population as 50 useless the males The reason behind this is men do not physically have children they are not childbearing When this is compared to asexual reproduction it is significantly less In asexual reproduction every organism reproduces not just the females Another cost to sexual reproduction is that organisms may be more susceptible to prey The need to reproduce is more profound than the need to survive For example a male peacock has brightly colored feathers that attract his female mate The brighter the feathers the more desirable the peacock is to the female This makes him more susceptible to being eaten but since the peacocks drive to reproduce and pass on his genes is more profound he takes the risk 2 What are some advantages of Sexual reproduction compared to asexual reproduction The two advantages of sexual reproduction are recombination and outcrossing Recombination is the shuffling of your own genes within you This is an essential procedure in sex Recombination mostly occurs during meiosis cell division when gametes occur and rarely in mitosis Outcrossing is when your given genes are mixed with your mates In simple terms outcrossing is when a male and a female have sex and create an offspring The result the offspring is the outcrossing outcome Both outcrossing and recombination s purpose is to create diversity that asexual reproduction can not create 3 Explain the Vicar of Bray Theory What is the limitation to this theory The Vicar of Bray Theory states that sexual reproduction exsits because it allows a species to adapt to its environment The only limitation to this theory is that in harsh climate sexual reproduction is not present asexual reproduction is 4 When looking at the process of natural selection selection between or within a species is always going to be more important than selection between or within a species Selection within a species is always going to be more important than selection between a species The example the Red Queen states is between a Cheetah and a Gazelle Natural selection on the gazelle species as a whole will be against the slow gazelle because the slow gazelle with be eaten by the cheetahs As a whole the gazelle species will become faster as all the slow gazelle die off The cheetah species as a whole will also become faster because the slow cheetahs that can no longer catch food the slow gazelle will die off as well 5 Explain the argument that sex was invented to repair genes What is the limitation to this theory Outcrossing and recombination can repair genes Sex can repair genes In sexual reproduction you can have multiple mutations occur within DNA but not all if any are present in the off spring DNA can repair its self through sex If humans were mutated to not being able to repair their damaged genes then they are not able to undergo recombination which is an essential procedure in sex Harris Bernstein created the theory that sex is essential to repair genes because it evolved from repair mechanisms The only limitation to Bernstein s theory is that even though sex came about from repair mechanisms doesn t mean that that is the sole reason sex exists 6 What is Muller s Ratchet A ratchet is a tool that men use with hardware It turns or cranks one way but will never turn back Muller took the analogy and applied it to mutations The idea that a population will keep accumulating mutations is because it is too rare for a mutation to randomly mutate back to its original way This applies more to asexual reproduction because in asexual reproduction you consistently make copies of the same mutated gene In sexual reproduction it is easier to hide or mask mutations When recombination and outcrossing occurs it will take that mutation and separate it to different chromosomes masking the effect and not having it presentable