Natural Selection of Appearance amongst Homo sapiens .

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

Garcia, J. Martin Garcia, M. Jose

September 31, 1993CSULA 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 ani-

mals, such as the Mallard, females choose their mate almost exclusively by good appearance, at-

tentiveness, 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, per-

sonality 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 vari-

ables.

(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 character-

istics commonly sought in a mate. One of the most striking differences included physical attrac-

tiveness. 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 con-

trast, Thiessen (1979) and Gregg (1980) (as cited by Buss 1985) proposed a tendency for individ-

uals to seek mates with phenotypic characteristics similar to their own. These similar character-

istics reflect similar genetic material and therefore increase the probability of the couple’s off-

spring relating to each parent by more than 50%, thus enhancing the parents genetic reproduc-

tion. * Purpose of the study. State the Hypothesis you will test In this study, the group (class) made observations to deter-

mine 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 ob-

servations of unusual versus common appearance of students on the campus of California

State University at Los Angeles. Some characteristics considered to be unusual were: dread-

locks, 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 fif-

teen-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 mak-

ing up the pair. Then, this probability; was multiplied by the total number of pairs to get the

number expected pairs.

100

17.7

82.3

% of total Females

778

138

640

# Females

1544 100 766Total

302 21.4 164Unusual

1242 78.6 602Common

Totals% of total Males# MalesAppearance

* 9.5 3.8 22 9Unusual Male &Unusual Female

99.9 100 232 232 Totals

* 14.6 13.9 34 32Common Male &Unusual Female

14.6 17.6 34 44

Unusual Male &Common Female

61.2 64.7 142 150

Common Male &Common Female

Observed ExpectedObserved Expected Pair Type

% Total of Pairs Number of 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 re-

sults in English (1-2 paragraphs long!)

RESULTS

Observations of 766 males and 778 females showed that there were more common indi-

viduals than unusual individuals on campus: 78.6% of males and 82.3% of females were com-

mon (Table I)*. Of the 232 male-female pairs observed, most were in the common male - com-

mon 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 de-

viation 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 suc-

ceed 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 of-

ten 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 SelectionLast name initials Article title/lower case except first word

Amer. Science 73: 47-51, 1985.Journal title/ underline or volume pages yearUse italics

Need maximum 3 references: one must be a book.

LITERARTURE CITED / Work Cited

1. Buss, D. M. Human mate selectionAmeri. Sci. 73:47-51, 1985.

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

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

3. Thiessen, D. D. and B. Bregg. Human Assortative mating 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.