Lecture 7: polyandry: where one female males with many males. this occurs due to high predation rates. Post birth: some organisms are k-selected: (comes when population means near carrying capacity of the environment) a period of population growth when population sizes become stable and relatively high. The environmental conditions are fluctuating: california gull have 1 or 2 offsprings per year ( k-selected, but as parents get older, the strategies shift to more r-selected. there are mechanistic process that changes how the family care for the offspring. Investment shift trait: shift from k to r-selected is analyzed by studying the residual reproductive value, as rrv decreases, the benefit of investing in current offspring increases. Throwing good money after bad: in evolution : future decisions are based on current concept and moving forward, the amount you invested is already gone, and no longer fits into the cost-benefit analysis.