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What is the meaning of the term “apex predator”? Apex Predators are predators with no predators of their own, residing at the top of their food chain. Zoologists define predation as the killing and consumption of another organism (excluding parasites and bacteria). In this context, "apex predator" is usually defined in terms of trophic dynamics. Apex predator species occupy the highest trophic level(s) and have a crucial role in maintaining the health of their ecosystems. The apex predator concept is commonly applied in wildlife management, conservation, and ecotourism. Apex predators affect prey species' population dynamics. Where two competing species are in an ecologically unstable relationship, apex predators tend to create stability if they prey upon both. Inter-predator relationships are also affected by apex status. What is the meaning of the term “keystone species”? A keystone species is a species that has a disproportionately large effect on its environment relative to its abundance. Such species play a critical role in maintaining the structure of an ecological community, affecting many other organisms in an ecosystem and helping to determine the types and numbers of various other species in the community. An ecosystem may experience a dramatic shift if a keystone species is removed, even if that species was a small part of the ecosystem by measures of biomass or productivity. Are prey species in danger of extinction due to hunter species, such as wolves? Wolves feed on prey species, but in most cases they manage the overall population, keeping the different species’ numbers stable. In this sense, their contribution to the ecosystem is positive. Moreover, when comparing the effect of human hunting to that carried out by wolves, the results are self-explicatory: humans contribute much more heavily to the elimination of various species than all hunter species combined. Why do wolves howl? To express themselves, wolves make use of a wide repertoire of growls, barks, whines, and squeals to communicate. However, the most famous method of communication is the howl. Wolves howl for any number of reasons. They may wish to attract a mate, bring the pack together, express sorrow and mourn, or even inform members of their own pack of their whereabouts. They may howl before a hunt, after consuming a kill, or when an intruder is present. Wolf pups may howl in distress or after they have been playing. Experienced observers note that there are different types of howls used for different occasions and ranging in duration from one to ten seconds. Across open territory, a wolf howl can be audible for ten miles. Such communal howls confuse listeners into believing they hear many more wolves than are actually howling. ----------------------------------------------------------------------------------------------------------------------------------------educational pathway: “Who’s afraid of the big bad wolf?” Vassiliki Markaki © Humans and wolves: friends or foes? Some thousands of years ago, humans decided to tame wolves in order to use them for hunting and guarding purposes. Some scientists argue that humans adopted those wolf pups that were less aggressive and better at begging for food. Thus, succeeding generations survived thanks to humans and became increasingly tame. Still, at the molecular level not much changed at all: The DNA of wolves and dogs is almost identical. However, in fables and fairy tales wolves have traditionally represented the evil. This trend especially escalated during the Middle Ages, leading wolves very close to extinction. Thus, from friends, humans and wolves ended up to be foes. ----------------------------------------------------------------------------------------------------------------------------------------educational pathway: “Who’s afraid of the big bad wolf?” Vassiliki Markaki ©