We’ve already covered one hypothesis for why menopause exists, but there is another main hypothesis for the advent of reproductive cessation, and this one is an adaptive one. Photo via Adobe Stock Picture it: as ancestral humans were expanding their populations across African savannahs in the Pleo-Pleistocene era (between 1.7 and 1.9 million years ago), the increasingly arid conditions meant that food sources were changing. Juveniles that were once able to gather food were no
Physiological, social, and environmental elements have influenced the evolution of the immense diversity in maternal behaviour across the mammalian order. There are two general phases of the establishment of maternal care in primates: the initial bonding or recognition phasethe maintenance or persistent attraction phase The first of these is essentially what occurs in the moments directly following birth – in which mom and baby get their introduction to one another. Photo via Adobe Stock This
In many anuran (frog and toad) species, females have a sperm-storage organ (a spermatheca) that enables them to keep sperm for long periods of time. This too can allow for the possibility of female choice when it comes to post-copulatory selection of a particular seed. Female fire salamanders (Salamandra salamandra) can store sperm for several months. They collect sperm deposits from many potential suitors during this period. Photo via Adobe Stock In this scenario, there
Optimal foraging theory predicts that when there is intense competition for preferred resources, organisms should increase their diet breadth to include other less optimal items. In this way, biological fitness is maximized by striking a balance between obtaining food and the amount of time and energy required to do so. Food Choices in Crowded Environments I am in complete agreement with optimal foraging theory on this one. I’m not a huge fan of the all-you-can-eat
Most foods that humans eat are altered in some way before we consume them. Our species has developed elaborate ways in which to change the properties of our foodstuffs. Why don’t we just forage around like the rest of the animal kingdom? Partly, it’s because raw meat or chemically defended plants would make us very sick. Homo sapiens are blissfully unaware that the majority of foods available to organisms in a natural setting come with
It can be argued that our species evolved just like any other and that all our actions are justified under the umbrella of what is considered to be natural. However, one could also argue that in many respects the actions of Homo sapiens are so far removed from those of our animal cousins that we cannot be classified in the same way. I have repeatedly observed that issues we Homo sapiens face in our everyday
The human female is a complicated creature. The selection of an appropriate mate is often an extremely difficult process that can lead to sadness and heartache when we get it wrong. It seems so simple in theory: choose a mate who is most likely to provide you and your offspring with the best possible combination of genes and other resources. Is this what goes through our minds when a “rebel without a cause” type of