Reproduction
So lets talk about sex. All animals need a way to pass on their genetic material to the next generation who can also pass on theirs."Reproductive success is defined as the passing of genes onto the next generation in a way that they too can pass on those genes." [1] But animals like the mule are not examples of reproductive success because the mule is sterile and cannot continue the passing of its family genes. There is another type of reproduction besides sexual which is asexual. This is how something like a bacteria can reproduce without the need of a mate. There are four types of asexual reproduction; I will break them down under this.
Budding- The formation of an organism from an individual that will develop into a new individual and sometimes fall off. In hydras a new organisms forms due to cell division in that on spot, after it matures it will fall off.
Binary Fission- A form of asexual reproduction that involves the splitting of a parent cell into two exact daughter cells. During binary fission the DNA molecule divides into two exact copies an go on to form two exact cells. Fragmentation- "Fragmentation is a form of asexual reproduction or cloning in which an organism is split into fragments. Each of these fragments develop into mature, fully grown individuals that are clones of the original organism."[2] Vegetative Propagation- A form of asexual reproduction in plants. It is a process where new organisms are formed without the use of seeds. Some plants do this by extended a stem under the ground to a father place and it grows into an individual but is the exact same as the plant it broke off from. (images are in order of listing) |
Mitosis vs Meiosis
Cell division and reproduction occurs in two ways for all organisms: mitosis or meiosis Mitosis is a process of cell division where one cell form two genetically identical daughter cells. Meiosis is the division of a cell that involves two cell divisions and end with four sex cells, each with half the number of chromosomes of the original cell. For us that would be 23 because we have 46 chromosomes in our other cells. Mitosis is used for the growth of tissue, fibers and membranes. Meiosis is used for the sexual reproduction of organisms. This occurs in all organisms.
What About Wombats?
It might be hard to believe but a female wombat has three vagina's. The side ones carry sperm to the two uterus's, while the middle vagina sends the joey down to the outside world.[3] The ureters, which carry urine from the kidneys to the bladder, pass through the gaps between the three tubes. In mammals, like us, the ureters develop in a different way, and don’t go through the reproductive system. This might also explain why marsupial embryos are born at such a premature stage of development. Unlike, other mammals marsupials don't have placentas. A wombats baby is very small when it leaves the vagina. It might be that with such a small tube to go down, it couldn't get any bigger before its birth.
Male wombats scrotum lie in front of the penis rather than behind. The penis is split into two sections to go with the two lateral vagina's of the female. It is called a bi-fold penis |