31. Though these population totals sound robust, the murrelets'reproduction rate is only about half what it should be, federal biologists say. 32. The slow reproduction rate of the Tenkile tree kangaroo may add to the risk factor of the species going extinct. 33. The slow reproduction rate would also mean that it simply takes longer to replace lost individuals or increase the population. 34. Because nutrition affects reproduction rates , a drop in nut production can also affect birthrates, lowering the number of new cubs. 35. But with an exponential reproduction rate and no enemies other than angry humans, the frog population in Hawaii has exploded. 36. For male mammals, which have a relatively fast reproduction rate , sexual selection leads to adaptations that help them compete for females. 37. The wandering albatross has no significant natural enemies, and this has enabled it to survive with such a low reproduction rate . 38. For female mammals, with a relatively slow reproduction rate , sexual selection leads to choosiness, which helps females select higher quality mates. 39. The normal figure is " net reproduction rate " which is the number of female children a woman will have on average. 40. If gradual change in the mix of genes and characteristics in a population occurs because of differential reproduction rates , it is evolution.
