Lecture 14 - Mating Systems Introduction General...

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Mating Systems - Introduction - General definitions - Classification of mating systems - Mating systems and ecology Introduction - Recall that parental investment is not the same for both sexes o In males Sperm represents a small investment 5% of the body weight throughout an entire breeding season o In females Eggs are big investments In some species, an egg can be 30% of an animal’s body weight - Since female investment > male investment o This leads to: Female choice and male-male competition for access to females This should favor polygyny But other mating systems exist: Monogamy Polyandry Promiscuity o Why? Some Basic Definitions to Know: - Monoga my: one m ale m at es with one fem ale during a single breeding s e ason - Polygyny: one m ale m at es with m ore than one fem ale during a single bre eding se ason - Polyandry: one fem ale m at es with m ore than one m ale during a single breeding s e ason - Promiscuity: m ultiple p artnering betwe en m ales and fem ales during a single bre eding se aso Emlen and Oring - Mating syst e m s tend to differ betwe en m a m m als and birds o Birds tend to be socially m onog a mous o Mam m als t end to b e polygynus - Why? - Mam m als vs Birds o Among birds, they observed that 90% of all species ar e socially m onog a mous a nd Nest sites and resources tend to be scatt ered a nd not d efendable Breeding se asons can be short Both sexes can care for young and young ne ed a lot of care to fledge o So for m ales, the gre at est chance for enh anc ed RS is to help raise their own young o By contrast, m a m m als tend to practice polygyny As in birds, fem ales m ake an extre m e reproductive invest m ent Fertilization a nd d evelop m ent is internal Only fem ales lactat e o How can thes e differences be explained? - Monoga my should be favored where feeding or nesting resources cannot be d efend ed so n e sex is a ble to m onopolize m ore than one m e m b er of the opposite sex - Basic observation resulted in Classification of Mating Systems - Mating Syst e m s
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
o Monogamy: Why does it exist? (Tinbergen’s 3 rd  question) HYP I: Mate-Assistance hypothesis HYP II: Mate-Guarding hypothesis HYP III: Female-Enforced hypothesis o Mating systems reflect the ability of one sex to monopolize mates or resources Resources = clumped Polygyny or polyandry Most mammals o
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern