BIOB51H3 Lecture Notes - Lecture 21: Allopatric Speciation, Coho Salmon, Mating Plug
Document Summary
Sexual dimorphism diferences in form or behaviour of males and females of one species: sexual dichromaism (color, structural dimorphism, sexual size dimorphism (body size, behavioural dimorphism e. g. frigate birds (male has red bladders); american toads (behavior) If: sexual reproducion creates diferent selecion pressures on females and males. Then males and females may have diferent strategies for maximizing their lifeime reproducive success (itness); because females generally invest more in each ofspring than do males. Parental investment: anything that increases the chance of survival of current ofspring while decreasing the ability ofthe parent to produce future ofspring (time and/or energy investment) Diferenial parental investment: parents invest diferent on ofsprings e. g. gamete dimorphism: eggs: nutrient rich; expensive; few produced. Females spend more energy on eggs/ day than males. Usually: maternal care (mother) > paternal care (father) In any given species, sperm are present in excess relaive to eggs = asymmetric limits on reproducive success.