Fertilisation

starting treatment. Another factor is smoking - in both partners. Smoking has been shown to reduce the chances of naturally conceiving and lowers the success rates of IVF. Cannabis can also seriously affect sperm quality and reduces the chance of fertilisation. So clinics recommend that couple wishing to undergo PGD cut down on smoking or preferably stop all together. Alcohol is also a factor which effects both men and women. In males, an excessive intake of alcohol, especially ‘binge’ drinking,…

Meiosis is the process where the male and female gametes fuse together to create a cell with the correct amount of chromosomes. Gametes contain a haploid number of chromosomes to ensure that after fertilisation, the diploid number of chromosomes is restored. The recombinant stage is when the random crossing over of genes at the same loci takes place (Appendix 8). This crossing over allows variation between organisms (OCR, 2008). Genes can be described…

Charles Darwin, associated with Cambridge University, revolutionized science with his theories of evolution. His ideas birthed new ways of understanding how species came to be. According to Darwin , the key driving force behind evolution is natural selection, which occurs under environmental pressures leading to speciation or changes within species. It favours the traits most adept to surviving in an environment’s conditions and weeds out those that are not through the four aspects of natural…

Pollination syndromes in large flowered plants. The land is more beautiful when it is that season of the year when flowers are scattered everywhere. Flowers are sunshine, food and medicine for the soul. A flower is sometimes called a bloom or blossom, it is the only reproductive structure found in flowering plants. Its biological function mostly it is to outcome reproduction through a mechanism of the amalgamation of sperm with eggs. They may go through what is called outcrossing and selfing. In…

Human Manipulations of Genetic Transfer and its Biological Implications For years, humans have been able to manipulate the alleles in animals for favourable traits through the use of selective breeding. But, now that technology has become so advanced, humans have developed a new process of manipulating the gene transfer through transgenesis, where scientists can create new alleles in animals. This essay shows how the selective breeding method and transgenesis method are carried out on the…

In the pro-oestrous stage of the cat’s oestrous cycle, the queen may start showing the first pro-oestrous behaviours, and these could start as early as four months of age. These behaviours include being more vocal than usual, restless and having an increased appetite. She may also show behaviours such as rolling on the floor and rubbing against objects. During this stage, the ovaries start to form follicles. Unlike in dogs, the vulva of the queen will only enlarge slightly and will appear…

STRESS AND FRUSTRATIONS AMONG ZIMBABWEAN BUSINESS MANAGERS (A CASE STUDY OF MARSH INSURANCE AND STOCK BROKERS ZIMBABWE) BY Chapter 2 LITERATURE REVIEW CONFLICT IN AN ORGANISATION Conflict is generally regarded as disagreement regarding interests or ideas (Esquivel and Kleiner, 1997). Organisational conflict is the discord that occurs when the goals, interests or values of different individuals or groups are incompatible and those individuals or groups block or frustrate each other`s attempt…

Plant Protection Assignment 5N2546 A. Pest and disease control measures and legislative control practices. 1. Describe five specific situations where pest and disease control measures are required. (5 pests) Slugs Symptoms The first signs that slugs are in your garden is probably that the leaves on plants are ripped or tore and that there are visible slime trails on the ground. Control measures Slugs can be dealt with in a number of different ways. They can be removed by…

The laws of heredity discovered by G. Mendel are similar for all complex life creatures and he concluded that genes come in pairs one from each parent inherited as distinct units. Also, the mathematical patterns of inheritance as well as genes segregation and their appearance in the offspring as dominant or recessive traits were determined during his genetic experiments with pea plants and outlined three laws oh inheritance. First, the Law of Dominance is expressed where one allele dominates…

Introduction It is estimated that there are one trillion species on earth despite all being originated from one common ancestor, LUCA. In this essay the importance and origin of diversity within species and between species is explored using Coleoptera as the taxonomic group. Coleoptera is the most dominant order of insects with 350,000-400,000 species, this is 40% of all insect species (Gillott, 1995) and the largest order in the animal kingdom. The degree of differences between individuals is…