Sperm Selection After Mating Essay

1032 words - 5 pages

A Bit of Background Information

What is pre- and post-copulatory sexual selection?
From the word copulatory, meaning to engage in sexual intercourse, pre-copulatory sexual selection refers to the female's choice in selecting a mate before sexual intercourse takes place. Post-copulatory sexual selection occurs within the female's reproductive track, and it describes the biological selection (whether due to sperm or the female's biology) that results in the fertilization her eggs.

Why are guppies good subjects for research in this topic?
The most significant reason for using guppies in sexual selection research is because they casually participate in polyandry. This means ...view middle of the document...

“Attractive” males in the guppy population—deemed attractive based on the female guppy’s affinity for them—were those with high levels of carotenoid coloration (orange, yellow, and red). Relative statures were also compared. The purpose of this experiment is to demonstrate, through artificial insemination, the role of postcopulatory sexual selection in a population of guppies. If guppy females are partial to specific traits, the propagation of those traits will be evident.

The Methods That Were Used

Prior to insemination, the behavior of the guppies involved was analyzed and one adult, non-virgin female and two sexually immature fish were put in observation tanks. The next day an adult male, unknown to the female, was placed in the tank and allowed to settle for 30 minutes. The courtship rate was then measured over a 10-minute period. This part of the experiment allowed its conductors to better understand female preference and mating behavior precopulation.

In this experiment, male guppies were randomly paired, anaesthetized, and photographed in order to measure length and body coloration—the alleged preferred traits. The blue, black, and orange color patterns were analyzed in each male, independent of paternity assignment. The number of sperm per bundle for each of the 23 males was obtained by repeated stripping, all of equal numbers. In each trial, equal numbers of bundles from each of the two males, groups A and B, were mixed and inseminated at the same time in the female via micropipette. The females were then revived from their previous anaesthetization and isolated until they produced offspring. Tissue samples were taken from each fish, and each male’s share of the paternity was measured using two micro satellite markers. Magnified pieces of the primer from each pair were separated by electrophoresis and paternity was assigned according to allele sharing between the guppies.

The James method was used to test fluctuations in the proportion of offspring by each male. Then, a linear model with binomial errors was used to determine the effects of male phenotype on the deviance of group B. Variables that didn’t cause significant change in the mode were excluded.

The Results of the Experiment


Other Essays Like Sperm Selection After Mating

Heart Disease and Nutrition Essay

1517 words - 7 pages inside the egg 4. Egg and sperm nuclei fuse together 5. Offspring development begins * Sperm lifespan is about 2-5 days; and sperm has 24 hours after ovulation to fertilize an egg, if not the sperm dies Twins * Fraternal Twins- Occurs when 2 eggs are ovulated and fertilized by 2 sperm * Identical Twins- Occurs from the splitting of the zygote or fertilized egg * Can happen during Pre-embryonic stage

Natural and Sexual Selection Essay

684 words - 3 pages behind only the large hard ones. The small beak birds weren’t able to survive with their small beaks and the large seeds. The last thing was that parents and their offspring has similar beak depths. After all of this they discovered that through natural selection an organisms shape, size and compositions were adapted to better their survival in their environment. (Boyd and Silk, 2006: 7-9) Sexual selection is separated into to different forms

Are Claw and Antenna Lengths Characteristics of Sexual Selection in Orconectues Rusticus?

1306 words - 6 pages longer claw lengths potentially due to (1) Male to male competition, (2) Holding down female, for mating (3) Being more attractive to female, as a sexual selection explanation. Furthermore as a natural slection explanation it could be because (1) defense and (2) Bigger prey. This also means that male crayfish had longer antennas in a sexual selection sense potentially due to (1) Wanting to find more mates and (2) Being more attractive. As a

Small Study

1433 words - 6 pages Introduction In recent decades researchers have generated considerable documentation on the evolutionary psychology of human mating strategies and romantic relationships. Much of this research

There Is No Perfect Research

802 words - 4 pages and so forth. This is proving that there is no perfect research and a research cannot accommodate complete facts of an entity lifetime and its infinitive coexistence with unpredictable environment. Example 2(Darwinian Theory on sex selection) Jonah Lehrer, on 6th Jun 2006, wrote an article about how Joan Roughgarden, a professor of biology at Stanford University, after some research challenged Darwin’s theory of evolution: sexual selection

Human Cloning: Simplest Way to Have a Designer Child

1117 words - 5 pages Rate This Article Should genetic engineering or human cloning be used to create designer babies? Every parent wants a perfect child - but what happens when a parent wants a designer child - a child built to order, a pedigree child, a super-breed, super-human or just a baby with higher intelligence? Sex selection is just the start of the process, a form of designer life: parents deciding that only a certain type of perfectly normal child

Crop Improvement

2075 words - 9 pages species. In the eighteenth and nineteenth centuries a conscious attempt was made to predict the performance of plants that could be expected from one seed generation to the next. The concept that ancestry was important in crop improvement led to refinement in the selection process, brought about by keeping records and the assessment of lineage. Furthermore it became obvious that variation could be managed by controlling the mating process, an

Biology HSC Syllabus - Blueprint Of Life - All Dot Points Answered

7675 words - 31 pages 9.3 - Blueprint of Life:1. Evidence of evolution suggests that the mechanisms of inheritance, accompanied by selection, allow change over many generations:•Outline the impact on the evolution of plants and animals of:•Changes in the physical conditions in the environment:•Changes in the chemical condition in the environment:•Competition for resources:-Evolutionary theory states that all organisms have developed from previous


4771 words - 20 pages • Researchers: biological answer • Needed to investigate: o Archaeology o Cultural anthropology o Linguistics • Holism crucial for solving the major riddle of human existence • Subfield of medical anthropology Sociobiology • Dr. Edward O. Wilson • Genetic Substrate underlying animal behavior • Social behavior results from evolutionary processes • Explains behavioral differences and similarities in terms of “natural selection” – Darwinian

Reproductive Health

1485 words - 6 pages were given at the start of the cycle it will remain same till the end. E.g. Brevicon (Ethinyl Estradiol i.e. estrogen 0.035mg and Norethindrone i.e. progestin 1mg), Aviane (Ethinyl Estradiol 0.02mg and L-Norgestrel 0.1mg) and Levora (Ethinyl Estradiol 0.03mg and L-Norgestrel i.e. 0.15mg) BIPHASIC: In these drugs dose of progestin is increased after 1/3 time period of cycle i.e. dose will increase from 8th day of administration, while the dose of

Is Jealousy Different For Men Than For Women?

1976 words - 8 pages preservation (Daly, Wilson, and Weghorst, 1982). They proclaim that different jealousy responses evolved as a consequence of the fact that ancestral men and women faced unique reproductive challenges. Due to unseen fertilization process, men could never be certain that they were genetically related to any children born to their partner. This paternity uncertainty was the greatest reproductive challenge faced by ancestral men. Subsequently, selection

Related Papers

Evolution Essay

4658 words - 19 pages THE ABSENCE OF NATURAL SELECTION *5 Causes of change in allele frequency in a population 1. Natural selection 2. Migration- gene flow occurs into or out of the population * Can alter allele and genotype frequencies 3. Non-random mating- mating is not random with respect to genotypes; ex. Some genotype might not mate 4. Genetic Drift: random change in allele (gene) frequencies from generation to generation most often occurs

Micaela Clat Essay

1748 words - 7 pages : Eliminate all forces of evolutionary change 1. Very large population (no genetic drift) 2. No migration (no gene flow) 3. No mutation (no genetic change) 4. Random mating (no sexual selection) 5. No natural selection (equal fitness) Microevolution Hardy‐Weinberg Principle • Hypothetical population at genetic equilibrium – No change in allele frequencies over generations • A testable model (null hypothesis) – Natural populations are

Biology Storybook/Report

437 words - 2 pages seems to be just for its own survival.After a series of people were born with resistance to the virus it started to die out, however the gene pool thrived in other individuals.After many years of research scientists found that the genes were in a state of non-random mating. Many variations of the virus have died off due to their lack of compatibility with people; this is an obvious form of natural selection or survival of the fittest. After 10 years

Deciding How To Decide Gender Selection

1440 words - 6 pages decline. There are four main ways to achieve gender selection: specialized invitro-feritilaztion, post conception abortion, adoption, and conceiving within the different timing of a woman’s ovulation. With invitro-fertalization, you can use sperm selection - a sample of sperm is collected and the XX (girl) and XY (boy) sperm are identified. Then only the gender of the parents' choice would be used to fertilize the egg. Also, after the embryo