Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Mate Choice

Mate Choice

Mate choice—the decision about whom to mate with—is a type of natural selection, since animals must reproduce to pass down their genes. Mate choice is also called intersexual selection because the behavior occurs between the sexes.

Chi-square Analysis

Chi-square Analysis

The chi-square test is a statistical hypothesis test. It is used to check whether there is a significant difference between an expected value and an observed value. In the context of genetics, it enables us to either accept or reject a hypothesis, based on how much the observed values deviate from the expected values.
The chi-square test was developed by Pearson in 1990.
The first step of performing a Chi-square analysis is to establish a null hypothesis, which assumes that there is no real...

The Ratio of X Chromosome to Autosomes

The Ratio of X Chromosome to Autosomes

In most organisms, sex is determined by the ratio of X and Y chromosomes. However, in some organisms, such as Drosophila and C.elegans, sex is determined by the ratio of the number of X chromosomes to the number of sets of autosomes. The Y chromosome in Drosophila is active but does not determine sex. It contains genes responsible for the production of sperms in adult flies.
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female Drosophila...

Testing a Claim about Population Proportion

Testing a Claim about Population Proportion

A complete procedure for testing a claim about a population proportion is provided here.
There are two methods of testing a claim about a population proportion: (1) Using the sample proportion from the data where a binomial distribution is approximated to the normal distribution and (2) Using the binomial probabilities calculated from the data.
The first method uses normal distribution as an approximation to the binomial distribution. The requirements are as follows: sample size is large...

Odds Ratio

Odds Ratio

The odds ratio (OR) is a statistical measure used extensively in epidemiology and research to quantify the strength of association between exposure and outcome across different groups. Unlike relative risk, which compares the probabilities of an event occurring, the odds ratio compares the odds of an event occurring in the exposed group to the odds of it occurring in the unexposed group. The odds, in this context, are calculated as the probability of the event happening divided by the...

Natural Selection and Mating Preferences

Natural Selection and Mating Preferences

The principle of natural selection posits that organisms better adapted to their environment are more likely to survive and reproduce. This principle is closely intertwined with mating preferences, a key aspect of sexual selection, which evolutionary psychologists believe is driven by instincts to propagate one's genes. Such instincts significantly influence mating behaviors and preferences between genders.
Females, due to their biological roles in conception, pregnancy, and nursing, inherently...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Complex foraging behaviours in wild birds emerge from social learning and recombination of components.

Philosophical transactions of the Royal Society of London. Series B, Biological sciences·2021

Same author

Diurnal variation in the production of vocal information about food supports a model of social adjustment in wild songbirds.

Proceedings. Biological sciences·2019

Same author

A high-density SNP chip for genotyping great tit (Parus major) populations and its application to studying the genetic architecture of exploration behaviour.

Molecular ecology resources·2018

Same author

STABILIZING SELECTION AND VARIANCE IN FIG WASP SEX RATIOS.

Evolution; international journal of organic evolution·2017

Same author

QUANTITATIVE GENETICS OF SEXUAL SIZE DIMORPHISM IN THE COLLARED FLYCATCHER, FICEDULA ALBICOLLIS.

Evolution; international journal of organic evolution·2017

Same author

Signalling of information that is neither cryptic nor private.

Journal of evolutionary biology·2017

Search research articles

Related Experiment Video

Updated: Jul 11, 2026

Assessing Differences in Sperm Competitive Ability in Drosophila

Assessing Differences in Sperm Competitive Ability in Drosophila

Published on: August 22, 2013

Sex ratios.

S A West¹, S E Reece, B C Sheldon

¹Institute of Cell, Animal and Population Biology, University of Edinburgh, West Mains Road, Edinburgh EH9 3JT, UK. stu.west@ed.ac.uk

|April 5, 2002

Summary

Sex ratio theory explains offspring proportions, but broad taxonomic patterns remain a puzzle. Further research is needed to understand why different species vary in adjusting their offspring sex ratios.

Area of Science:

Evolutionary biology
Behavioral ecology
Genetics

Background:

Sex ratio theory successfully explains offspring proportions at species, population, individual, and brood levels.
Existing models provide qualitative and quantitative explanations for sex ratio variation in many organisms.

Purpose of the Study:

To address the challenge of explaining broad taxonomic patterns in sex ratio variation.
To investigate the reasons behind the diverse strategies organisms employ to adjust their offspring sex ratios.

Main Methods:

Comparative analysis of sex ratio adjustment strategies across diverse taxa.
Review of existing literature on sex determination and reproductive strategies.
Hypothesis generation for factors influencing the precision and extent of sex ratio adjustment.

More Related Videos

Determining the Egg Fertilization Rate of Bemisia tabaci Using a Cytogenetic Technique

Determining the Egg Fertilization Rate of Bemisia tabaci Using a Cytogenetic Technique

Published on: April 1, 2019

Visually Sexing Loggerhead Shrike (Lanius Ludovicianus) Using Plumage Coloration and Pattern

Visually Sexing Loggerhead Shrike (Lanius Ludovicianus) Using Plumage Coloration and Pattern

Published on: March 8, 2020

Related Experiment Videos

Last Updated: Jul 11, 2026

Assessing Differences in Sperm Competitive Ability in Drosophila

Assessing Differences in Sperm Competitive Ability in Drosophila

Published on: August 22, 2013

Determining the Egg Fertilization Rate of Bemisia tabaci Using a Cytogenetic Technique

Determining the Egg Fertilization Rate of Bemisia tabaci Using a Cytogenetic Technique

Published on: April 1, 2019

Visually Sexing Loggerhead Shrike (Lanius Ludovicianus) Using Plumage Coloration and Pattern

Visually Sexing Loggerhead Shrike (Lanius Ludovicianus) Using Plumage Coloration and Pattern

Published on: March 8, 2020

Main Results:

Significant variation exists in the degree and accuracy of offspring sex ratio adjustment among different taxonomic groups.
Current theories do not fully account for the observed broad-scale patterns in sex ratio variation.
The precision of sex ratio adjustment appears linked to factors such as parental investment and ecological conditions.

Conclusions:

Explaining the diversity of sex ratio adjustment strategies across the tree of life remains a key challenge in evolutionary biology.
Further research is required to develop comprehensive models that integrate ecological, genetic, and life-history factors.
Understanding these patterns is crucial for a complete picture of reproductive strategies and evolutionary dynamics.