module 4.4 Flashcards
what is fitness?
-natural selection favours individuals that produce the maximum number of reproducing offspring in a lifetime
what is life history influences?
-degree of parental care and investment
-age at first reproduction
-longevity
-number of offspring per reproductive event
-size of offspring at birth
-gender allocation
-habitat and how it is used
what is life history?
-there is a trade-off between the number of offspring and their size (ore offspring, the smaller the size of each)
-under unpredictable or disturbed environments, increasing allocation of offspring number increase the odds that at least a few will survive (parents that have fewer offspring invest more in each)
what is parental care?
-precocial vs. altricial young
-precocial= active, mobile at birth
-altricial= helpless, naked, blind, require more care from mother
what is parental investment?
-costs of reproduction are high
what is semelparous?
-invest all into growing up to reproduce once in a suicidal effort (die after)
-ex: annual plants
what is iteroparous?
-spend energy on reproduction in bouts over the lifetime
-ex: large animals
in general, higher rates of _____________
in general, higher rates of adult mortality select for early age at first reproduction and vice versa
why is there a trade-off between survival and reproduction?
antagonistic pleiotropy
-the strength of selection is greater early in life to benefit the organism’s fitness. A decline in strength of selection is seen later in life
-ex: in male humans is the gene for the hormone testosterone. In youth, testosterone has positive effects including reproductive fitness but, later in life, there are negative effects such as increased susceptibility to prostate cancer
-ex: the p53 gene which suppresses cancer, but also suppresses stem cells which replenish worn-out tissue
what are examples of antagonistic pleiotropy?
what is life history classification of r strategists?
what is life history classification of K strategists?
what is the fast-slow continuum pace of life (life history classification)?
r and K are ends of a continuum; most organisms fall between two
