Chapter 46: Reproduction By Carine Kessie

Charlene Forest is an associate professor in the Biology department at Brooklyn College, who dedicates her research in to trying to understand the mechanism behind the process of fertilization in algae, as well as what controls expression of gamete-specific genes. To do so, she must understand how sperm and egg gametes first recognize and then fuse with each other. Thus, in order to find what causes the fusion of these gametes, Forest’s lab is cloning genes that prevent the fusion of sperm and egg gametes. She hopes that her research on the fertilization process in algae will help understand the fertilization process in other organisms, particularly humans.

Fertilization in animals is similar to that in plants because its first cellcell change occurs after gamete fusion rises in the cytoplasmic Ca2+ levels as it does in animal gamete fusion. Also, the plants make a block to polyspermy, which is the fertilization of an egg by more than one sperm cell, as do the animal’s cell’s eggs.

A form of reproduction that requires two parents, rather than one, which introduces the possibility of genetic diversity.

Judson contributes to onefs understanding of sex among different organisms in that she makes difficult concepts simple to comprehend. Although she uses scientific terminology, she limits it so that anyone can understand the technical information she shares. Judson also describes the types of environments in which each species and

One advantage of sexual reproduction is that these organisms generally have greater genetic diversity. Organisms who reproduce asexually, on the other hand, are essentially clones of each other. This means that their predators can adapt to hunt them easily. The diversity of sexually reproducing organisms allows them to stay a step ahead of their predators because of their genetic variations and their ability to adapt via natural selection (Brockmyre 2015).

Ceratopteris richardii, known as a C-fern has a lifecycle referred to as alteration of generations, which consist of neither haploid nor diploid dominant. C-ferns are homospours plants which are important in that they can produce hermaphrioditic gametophytes in order to be able to self fertilize. However, some of the homospourous C-ferns only produce male gametophytes .The life cycle of Ceratopteris richardii starts as a diploid sporophyte which then, by meiosis, produces haploid spores. These spores then undergo mitosis to produce a haploid gametophyte, which can be either hermaphrodite( producing eggs and

This study was performed in order to gain more knowledge on mitosis and meiosis. This lab was done by observing mitosis in plant and animal cells, comparing the relative lengths of the stages of mitosis in onion root tip cells, stimulating the stages of meiosis, observing evidence of crossing-over in meiosis using Sordaria fimicola, and estimating the distance of a gene locus from its centromere. Mitosis is the scientific term for nuclear cell division, where the nucleus of the cell divides, resulting in two sets of identical chromosomes. Mitosis is accompanied by cytokinesis in which the end result is two completely separate cells called daughter cells. There are four phases of mitosis: prophase, metaphase, anaphase and

Throughout decades, sexual selection has been acknowledged in the explanation of evolutionary patterns. With research, we have had the opportunity to study species of animals like the Syngnathidae family. Animals that are included in this category include pipefish, seahorses, and sea dragons. This species is known for their sex role reversal, meaning that the male fertilizes and carries the eggs during incubation after the female has laid them. When we look more specifically at the pipefish, it is found that males are left with most of the parenting and care for the offspring. As the male carries its eggs, it supplies them with nutrients and oxygen through the placenta. During pipefish copulation, the female transfers her eggs through a small

There are many methods of reproduction, but the two main methods are sexual and asexual, but which one is more efficient or beneficial. Sexual reproduction is the fusing of two gametes to produce an offspring. This form of reproduction is used by a lot of organisms, including us. Asexual reproduction is reproduction that only involves one parent. (“Pros and cons of sexual and asexual reproduction”). I am going to focus on asexual reproduction and the Desert Grassland Whiptail Lizard. This unique lizard uses asexual reproduction. Asexual reproduction is better for this species of lizards because it only requires one parent, it is less risky, and the population is only female.

Without sexual reproduction in humans, offspring would just not be produced as our species have not evolved to reproduce without the crucial two sex cells from the male and the female. A process known as chiasmata, the switching of genetic material to create new combinations of chromosomes for the offspring from the mother and father, is very important as it states that through chiasmata, sex produces greater variation as the recombination hatches a product that contains genetic information unlike any other, making offspring that natural selection can work with instead of against. This process also removes harmful mutations throughout generations through the ‘recombination’ of chromosomes. August Weismann and Darwin agree on this concept but instead of believing that sex benefits purely the individual, Weismann stated that it was a benefit to the population, as the combinations of good and bad genes would be made evenly and would cancel any benefits for the individual. However, the benefits would only be seen after several generations when natural selection eventually eliminates the bad combinations. For example, it is beneficial when a large amount of variation exists within a population

There is an additional cost of reduce fitness for organisms in which the genders are separate. Also, there is another cost known as the cost of meiosis, which means that in sexual reproduction, only half of the genes are passed on to the next generation. On the other hand, there are some important benefits in sexual reproduction including purging harmful mutations and creating genetic variation that assistances offspring deal with the variations in the environment. In contrast, asexual reproduction creates clonal offspring only if the parents are perfectly adapted to the

Asexual reproduction is one parent reproducing an offspring that are genetically alike. The purpose of asexual reproduction is so that the reproductive process can go faster without any mistakes. Sexual reproduction is a combination of genetics from the patents to reproduce an offspring. The purpose of sexual reproduction is so that evolution can take place from the organism. The animal focus today is the desert grassland whiptail. The whiptail tail uses asexual reproduction. This whiptail uses the more beneficial reproduction because fertilization is not needed, so only one parent is involved. Also, their is a high chance that the offspring would be created successfully.

In Generation 3, we can see there is different pairs of color dot in the sexual experiment which produced different color dots than the original one. For example, the same 2 color dot can produce different color offspring, as the chart above, two lime produces 2 cream 4 lime and 2 brown. In Asexual chart, the color of parent can only reproduce 1 type of offspring, because they reproduce as single, and there is no diversity in each individual. Thus, Sexual reproduction has more diversity than Asexual reproduction. Asexual reproduce from single parent, there is no way to reproduce variation, they are the individuals that have to same DNA from their parent, their traits are the same automatically. In other hands, There are 2 parents reproduce offspring in Sexual reproduction. Their offspring is combine with the sperm and egg from the parents, and the sperm and egg include different chromosomes which has two different traits from the male parents and the female parents, then the offspring include some traits from the male parents and some from the female. Over time, the offspring

a. Asexually reproducing populations grow at twice the rate of sexually reproducing populations. This is because every asexual organism has a potential of giving birth however, in sexual populations the male gender cannot reproduce.

Asexual reproduction is a type of reproduction that creates uniform offspring. Asexual reproduction occurs mainly in single-celled organisms (organisms with one cell), and in a few multicellular organisms (an organism with more than one cell). Two examples of single-celled organisms are bacteria and amoeba. Bacteria is a single-celled organism forming one of the three domains of life. Amoeba is a single-celled animal that catches food and moves about by extending fingerlike projections of protoplasm. Asexual reproduction requires one parent, and the