New User Special Price Expires in

Let's log you in.

Sign in with Facebook


Don't have a StudySoup account? Create one here!


Create a StudySoup account

Be part of our community, it's free to join!

Sign up with Facebook


Create your account
By creating an account you agree to StudySoup's terms and conditions and privacy policy

Already have a StudySoup account? Login here

Chapter 7: Sexual Selection

by: Erica Leonard

Chapter 7: Sexual Selection BIOL 515

Marketplace > Kansas State University > Biology > BIOL 515 > Chapter 7 Sexual Selection
Erica Leonard
GPA 3.0
Behavioral Ecology
Eva A Horne

Almost Ready


These notes were just uploaded, and will be ready to view shortly.

Purchase these notes here, or revisit this page.

Either way, we'll remind you when they're ready :)

Preview These Notes for FREE

Get a free preview of these Notes, just enter your email below.

Unlock Preview
Unlock Preview

Preview these materials now for free

Why put in your email? Get access to more of this material and other relevant free materials for your school

View Preview

About this Document

main ideas and concepts discussed in chapter 7
Behavioral Ecology
Eva A Horne
Study Guide
50 ?




Popular in Behavioral Ecology

Popular in Biology

This 4 page Study Guide was uploaded by Erica Leonard on Thursday October 22, 2015. The Study Guide belongs to BIOL 515 at Kansas State University taught by Eva A Horne in Summer 2015. Since its upload, it has received 38 views. For similar materials see Behavioral Ecology in Biology at Kansas State University.


Reviews for Chapter 7: Sexual Selection


Report this Material


What is Karma?


Karma is the currency of StudySoup.

You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!

Date Created: 10/22/15
Chapter 7 Sexual Selection Sexual Selection gt Characters contributing to finding amp keeping a mate are selected Darwin 1871 o Intersexual selection 1 gender chooses the other female choice 0 ntrasexua selection competition over 1 gender females within the other gender males 0 Parental investment differences in amount of energy materials time etc put into producing offspring Gametes gt Maximizes fitness Females produce few large gametes eggs Males produce many small gametes sperm 10 eggs 10000 sperm Low investment high potential high levels of sexual activity competition of mates High investment low potential low levels of sexual activity selection among mates 0000 I Example Pipefish Males choose largest and most ornamented female females who display for longer periods of time But males are limited to how many zygotes they can carry in their pouch ntrasexua Selection gt Competing for access to opposite gender gt Gaining copulations o Dominance amp fighting exclude others through conflict can lead to sexual dimorphism I Differences between gender males larger stronger w more weapons 0 Dominance amp hierarchies form linear rank system ordering individuals from most least dominant decides who gets first choice on females 0 Alternate male strategies how to safely avoid dominant male amp mate anyway I Mimic females males get close enough to dominant males nest to releases sperm at same time as DM and fertilize eggs I Satellite males wait quietly near displaying male amp intercept incoming females 0 Ensure use of males sperm I Male guarding Guard female from other males timing depends on whether females stores sperm amp sperm she decides to use Males lose weightfitness from guarding females and not leaving to eat I Displace or inactivate rival sperm sperm competition Quality of sperm based on mobility and numbers How many mates female had before male order depends Tactics 0 Remove rival male sperm from female 0 Seal rival male sperm off inside female 0 Stimulate female to eject rival male sperm 0 Produce quotkillerquot sperm Iepidopterans bigger sperm produced that attacks rival ales sperm and doesn t fertilize eggs 0 Advantages to females of multiple copulations I Why allow sperm competition Increase probability of Increase genetic diversity of Accumulate benefits from Increase diversity of mating o Interfere with rival male I Sexual sabotage reduces rival s fitness by Infanticide male destroys offspring of rivals o Occurs in males only kill nonkin brings females into estrous Intersexual selection gt one gender chooses the other female choice gt characteristics chosen 0 Material benefits qualityquantity of resources provided by males I Improve females survivalability to reproduce I Improve survival of offspring o Nuptial gifts foodvaluable substances presented to female during courtship birdsinsects I Prey seminal nutrients gland secretions body parts I Make males appear for desirable I Easier to copulate I Maximize amount of sperm I Parental investment to offspring Red backed spider 0 Male transfers sperm somersaults so abdomen can be eaten by spider increases copulation timeeggs fertilized eating male decreases chances of 2quot l mate if male survive to mate again ensures 100fetilization 0 Larger males are able to constrict abdomen in order to survive first copulation come back for 2quot l mating dies within 24hrs post mate 0 Mates that don t survive fertilize more eggs due to longer copulation time o Territory quality ampor size of area defended by male I Good nest or oviposition site low predation risk good forage o Sufficient sperm females are picky about mates I In some species females choose males that haven t mated recently occurs in species that package sperm with nutrients and other substances 0 Parental ability ability of male to defend ampor feed offspring choose based on character that correlates to good parental care I Large sizebetter defenderprovider I Large epaulettes better defenderintensity of courtship feeding effort I Quality of nutritional gifts ability to forage provide I Previous experience w male successful choosing him again 0 Other male qualities I Flashy colors red orange yellow can t be made by body Can indicate physical condition foraging ability or parasite load Bright males 9 better fathers feed offspring more 9 brighter sons pass more of females genes on I Song repertoire I Display objects birds that collect rare blue objects to display for females Female mate choice of traits offering no material benefit gt Why do females prefer flashy males gt Why do traits persist when they reduce male survival 0 Runaway selection coevolution of female preference amp male character I Female develops preference for male character sonscharacter daughters preference 0 Handicap principle I Male s exaggerated trait makes him less likely to survive I Female chooses him because he survives despite the quothandicapquot 0 Good genes females chooses male that can pass on the best adapted traits I Peacock 0 Females choose males w most eyespots on tail of those she visited 0 More eyespots 9 survived better healthier o More elaborate tail 9 heavier offspring 9 higher survival rate 0 Parasite load color or other traits indicates of parasites male has I Flashy males more resistant to parasites good genes for young healthierbetter parents 0 Symmetry animals with bilateral symmetry both sides equal proper development good genes good health I Female preference indicates resistance to mites I Birds regrow feathers after molting if they have mites9tai regrows unevenly 0 Genetic differences degree to which prospective mate has same genes I Major histocompatibility complex MHC region on chromosomes important in immune response antibody production I Avoid inbreeding I May increase offspring s resistance to disease by having more variable immune system 0 Sensory bias male traits evolved to take advantage of some preexisting bias of females I Females of genus Xiphophorus prefer males w long swords possibly evolved from female preference of large body size o Males increase total length to equal males w sword amp preference disappears o Prefer males with large bodies size not necessarily longer sword tail 0 Matechoice copying male becomes more attraction to female if another female is attracted to him first I Younger females learn what traits are best by observing older females in species I When allowed to choose female will choose same male as 1 female less experienced copy more experienced but not vis verse Male mate choice gt Males provide much care to offspring pipefish gt Female has mated before amp 1St male s sperm gains priority 13lined ground squirrels gt Females reproductive capacities are different amp predictable choose largest female because they can lay the most eggs Summary or sexual selection gt Two kinds 0 Intersexual selection female choice 0 Intrasexual selection malemale competition gt Differences based on initial differences on parental investments 0 Males Low investments amp max fitness by copulating w as many females as possible 0 Females High investments amp max fitness by choosing best male gt Many tactics for each depending on species amp circumstances gt Reversals of roles do occur


Buy Material

Are you sure you want to buy this material for

50 Karma

Buy Material

BOOM! Enjoy Your Free Notes!

We've added these Notes to your profile, click here to view them now.


You're already Subscribed!

Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'

Why people love StudySoup

Bentley McCaw University of Florida

"I was shooting for a perfect 4.0 GPA this semester. Having StudySoup as a study aid was critical to helping me achieve my goal...and I nailed it!"

Janice Dongeun University of Washington

"I used the money I made selling my notes & study guides to pay for spring break in Olympia, Washington...which was Sweet!"

Jim McGreen Ohio University

"Knowing I can count on the Elite Notetaker in my class allows me to focus on what the professor is saying instead of just scribbling notes the whole time and falling behind."


"Their 'Elite Notetakers' are making over $1,200/month in sales by creating high quality content that helps their classmates in a time of need."

Become an Elite Notetaker and start selling your notes online!

Refund Policy


All subscriptions to StudySoup are paid in full at the time of subscribing. To change your credit card information or to cancel your subscription, go to "Edit Settings". All credit card information will be available there. If you should decide to cancel your subscription, it will continue to be valid until the next payment period, as all payments for the current period were made in advance. For special circumstances, please email


StudySoup has more than 1 million course-specific study resources to help students study smarter. If you’re having trouble finding what you’re looking for, our customer support team can help you find what you need! Feel free to contact them here:

Recurring Subscriptions: If you have canceled your recurring subscription on the day of renewal and have not downloaded any documents, you may request a refund by submitting an email to

Satisfaction Guarantee: If you’re not satisfied with your subscription, you can contact us for further help. Contact must be made within 3 business days of your subscription purchase and your refund request will be subject for review.

Please Note: Refunds can never be provided more than 30 days after the initial purchase date regardless of your activity on the site.