EEB2244%Lecture%Guide% Lecture%11:%Reproductive%Strategies% Page%1%%Reproductive Strategies • Asexual vs. Sexual reproduction • Forms of sexual reproduction • Mating systems • Sexual selection Asexual reproduction results in ______________________________ Advantages 1. 2. Some vertebrates can reproduce asexually….Examples? What is sexual reproduction? Gametes are produced by_______________ Male and female ______________________________ fuse to form a ____________________________ Mixes the ______________________________ Disadvantages of sexual reproduction: Advantage of sexual reproduction: Forms of sexual reproduction Separate males and females Plants : Male and female organs on the same individual Plants : Animals :EEB2244%Lecture%Guide% Lecture%11:%Reproductive%Strategies% Page%2%%Simultaneous vs. sequential sex expression: Protogynous – Protandrous – Why have separate sexes? Advantage: Disadvantage: Monoecy/Hermaphrodism occurs where _______________________________ overcomes fixed costs of ______________________________ Simultaneous hermaphrodite. Example? Sequential hermaphroditism depending on the environment. Examples? Mating systems Mating system = Monogamy __________________ per breeding season Polygamy _______________ per breeding season 1. Polygyny Individual males mate with > 1 _______________ 2. Polyandry Individual females mate with > 1 _______________ 3. Promiscuity Both males and females mate with _______________EEB2244%Lecture%Guide% Lecture%11:%Reproductive%Strategies% Page%3%% How does parental investment affect mating systems? The sex that makes the _______________ investment will be _______________ discriminating E.g., costly eggs in females + cheap sperm à __________________________________ Unequal parental effort leads to 1. 2. 3. Equal parental effort leads to 1. 2. 3. Criteria for polygyny (e.g., Red-winged blackbirds) Males arrive first and establish territories Territories differ in quality for raising young First females mate with best males Late females decide between _______________ males on ______________ habitats and ____________ Polygyny Threshold Model Polygyny threshold – Polygyny only occurs where ______________________________ that polygynous females have _______________fitness than _______________ females How do arriving females decide on a territory? Sexual Selection Individuals differ in ______________________________ Sexual selection –EEB2244%Lecture%Guide% Lecture%11:%Reproductive%Strategies% Page%4%% Traits that increase mating often ______________________________ Conflict between _______________ and _______________ selection Often leads to _______________ Which sex is larger? 1. Females > males Females produce ____________ gametes, offspring _____________ constrained 2. Males > females Sexual selection in long-tailed widow birds Manipulate tail lengths to show mating success Cost? Benefit?