Natural Selection of Appearance amongst Homo sapiens.

[Note: The title must be in scientific language.]

Garcia, J. Martin

Garcia, M. Jose

September 31, 1993

CSULA Biology 01

* Main Objective: Explain how your study fits into the context of biology.

Give the reader a background.

  • [(3)–(4)] Two important generalizations about Mate Selection follow with supporting points from the literature citations.
  • At the end of the introduction clearly and scientifically state your

HYPOTHESIS!

  • (Should be 2-3 paragraphs long!)

INTRODUCTION

(1) Many factors determine the way in which different species select a mate. In some animals, such as the Mallard, females choose their mate almost exclusively by good appearance, attentiveness, displays and aggressiveness of the male (Weidmann 1990). In another species, the Mormon cricket, the male chooses the mating partner and discriminates among females by their capability of producing offspring (Gwynne 1981). Variables studies in Homo sapiens mating are: age, ethnic origin, religion, socioeconomic status, intellectual and cognitive variables, personality traits, social attitudes, and physical appearance (Buss 1985).(Name & date should appear in Lit. Cited section) Buss has shown that humans tend to mate with someone who is similar in many of these variables.

(2) Darwin called intersexual selection “female choice,” because he observed that throughout the animal world females tend to be more discriminating in their choice of mates than males. Buss and Barnes (1985)(Name date should appear in Lit. Cited section) showed how males and females rated characteristics commonly sought in a mate. One of the most striking differences included physical attractiveness. Men ranked attractiveness third, while women ranked in a sixth, suggesting that women more often seek partners according to attributes other than physical appearance. In contrast, Thiessen (1979) and Gregg (1980) (as cited by Buss 1985) proposed a tendency for individuals to seek mates with phenotypic characteristics similar to their own. These similar characteristics reflect similar genetic material and therefore increase the probability of the couple’s offspring relating to each parent by more than 50%, thus enhancing the parents genetic reproduction. * Purpose of the study. State the Hypothesis you will testIn this study, the group (class) made observations to determine the significance of physical appearance in the mating selection of Homo sapiens.

  • Main Objective: to give the reader enough details about your procedure that they are able to repeat your experiment (1-3 paragraphs long!)

MATERIALS AND METHODS

*Main goal of the study On September 30, 1993, 10 groups, each group consisting of two people,made observations of unusual versus common appearance of students on the campus of CaliforniaStateUniversity at Los Angeles. Some characteristics considered to be unusual were: dreadlocks, colored hair, shaved heads, Mohawks, and men with long hair. Furthermore, it was a hot day so clothing considered unusual included: raincoats, formal wear, ties, ethnic clothing, high heels, any hat other than a baseball cap, and many warm clothing. For a fifteen-minute period, from 10:45 until 11:00 A.M., each group recorded the sex and appearance of all the people they saw. During the next fifteen minutes, from 11:00 until 11:15 A.M., each group observed only male-female pairs. For each pair, the appearance of each gender was recorded. The Chi-square analysis of expected pairs from the observed values of individuals was recorded. The probability of each type of pair was determined by multiplying the frequency of one type of individual in the general population times the frequency of the other individual making up the pair. Then, this probability; was multiplied by the total number of pairs to get the number expected pairs.

* Main Objective: (1)A visual representation of the results

(The main facts). For example, graphs, tables, photographs, etc.

Note: Title, headings, legend, and labels – must explain what the

numbers mean.

  • The reader should understand the results without reference to the

verbal description.

DATA

legend → Table I Represents a general survey of CSULA common and unusual students.

legend →Table II Male-female pairs survey of CSULA students. * Significantly different

from expected at p < 0.05.

  • Main Objective: Verbal description of your data

(Using Math & English).

  • (2) A written description and representation of the main results in English (1-2 paragraphs long!)

RESULTS

Observations of 766 males and 778 females showed that there were more common individuals than unusual individuals on campus: 78.6% of males and 82.3% of females were common (Table I)*. Of the 232 male-female pairs observed, most were in the common male - common female category as we expected (Table II)*. A difference between the expected number and the observed numbers was apparent. Using Chi-square analysis of the test, the calculated Chi-square value was 20.5 (DF=3, p < 0.05, accept null hypothesis if X2 7.8). The high Chi-square value suggested that a significant difference existed between the expected numbers of pairs if members were selected at random and the observed numbers of pairs seen at CSULA campus (Table 2)*.

* NOTE: You should make sure that the reader understands the basic results from the verbal presentation, without looking at the visual presentation.

(1) Verbal statement of results.

(2) Verbal statement of statistical results.

(3) Make sure that the reference to visual

representation of the results is clear.

(4) NO DATA should be in this part of the report!

______

* Main Objective: interpret your results/data and explain how they relate to the existing literature (At least two scientific journals must be discussed) on this topic(3-5 paragraphs long!)

DISCUSSION

In this study, the results of a chi-square analysis test show that there was an association between appearance and the probability of mating. Assortative mating, defined as the coupling of individuals based on their similarity on one or more characteristics, it is the most common deviation from random mating in Western societies (Buss 1985). Unusual female and males were much more likely to mate then their random probability projected. This finding is in accord with Thiessen (1979) and Gregg (1980) who stated that there is a tendency for individuals to seek mates with similar characteristics. Furthermore, one deviation from randomness never reliably demonstrates is the tendency of opposites to marry or mate (Buss 1985).

A common female was less likely to choose an unusual male (see Table 3). Feasibly, “clean cut” and common looking males may be more likely candidates for employment. During this project the team observed many more common people than unusual people. Thus it suggests that employers in higher paying careers may look for more common looking males because the public may be more likely to accept them. Therefore common males may be more likely to succeed in business. Buss (1985) supported this theory in studies that supported the fact that women valued the characteristics of good earning capacity much more than males did. This supported Darwin’s theory that females are more discriminating in choosing a partner.

The observed common male-common female pairs and common male-unusual female pairs were both to their expected values. The mating in these cases could be due to random probability and appearance may not have had an effect.

  • Main Objective: More interpretation of your results/data and explain how they relate to the existing literature on this topic (2-3 paragraphs long!)

(a)Explain errors and possible improvements, and state your final conclusion in agreement or disagreement with your hypothesis.

(b)Give/State the points that prove or disprove your

hypothesis(falsifiable!)

CONCLUSION

(a)This study could have been more accurate by changing the method of obtaining data. Instead of having two people observe individuals for fifteen minutes and then pairs for fifteen minutes, the two people should observe couples for thirty minutes. One person could record the appearance of individuals while the other person records the pair combination. Furthermore, we would need to question each pair to determine whether or not they were actually a couple and if so, it was their mate’s physical appearance that originally brought them together.

(b)The findings reported in this lab report strongly suggest that physical appearance does have a significant influence on mating selection in Homo sapiens. Individuals most often pair up with someone like themselves (See Table 1). In the mating where the individuals were not alike, the female would tend to seek a male of a higher standard (See Table 2.)

  • Main Objective: citations are in alphabetical order and numbered.
  • Example:
Buss, D. M. Human mate Selection

Last name initialsArticle title/lower case except first word

Amer. Science 73: 47-51, 1985.

Journal title/ underline or volume pages year

Use italics

  • Need maximum 3 references: one must be a book.

LITERARTURE CITED / Work Cited

  1. Buss, D. M. Human mate selection

Ameri. Sci. 73:47-51, 1985.

  1. Gwynne, D. T. Sexual Difference Theory: Mormon Crickets show role

reversal in mate choice. Science 213:779-780, 1981.

  1. Thiessen, D.D. and B. Bregg. Human Assortativemating and genetic

equilibrium: An evolutionary perspective. Ethol and sociobiol. 1:111-140,

1980.

ACKNOWLEDGMENT

This is where you thank anyone who has help in the experiment or writing of your lab report. All reports should have acknowledgment section.