"Nature" - what is it, definition of the term
The term refers to the entirety of the physical universe and its living components, encompassing ecosystems, geological formations, atmospheric processes, and the myriad organisms that inhabit them. It includes all biotic entities, from microscopic parasites such as ticks, true bugs, lice, and fleas to the largest mammals and plants, as well as the abiotic forces—gravity, climate, and chemical cycles—that sustain their existence. This comprehensive system operates through interdependent relationships, energy flows, and material transformations without human design, constituting the observable reality that science studies and humanity experiences.
Detailed information
Ticks belong to the subclass Acari, order Ixodida. Adult females engorge on blood, expanding up to three times their unfed weight. The life cycle comprises egg, larva, nymph, and adult stages; each active stage requires a blood meal from a vertebrate host. Host selection varies among species, ranging from small mammals to large ungulates. Pathogen transmission occurs during prolonged attachment, with agents such as Borrelia, Rickettsia, and viral encephalitis agents commonly associated.
True bugs, members of the order Hemiptera, possess piercing‑sucking mouthparts adapted for extracting plant sap or animal fluids. Their exoskeleton features a partially hardened forewing (hemelytron) and a membranous hindwing. Species occupy diverse habitats: aquatic environments host water striders, while terrestrial niches support stink bugs, aphids, and cicadas. Many hemipterans serve as agricultural pests, feeding on crops and transmitting phytopathogenic viruses.
Lice represent obligate ectoparasites of the order Phthiraptera. Three primary groups affect humans: head lice (Pediculus humanus capitis), body lice (Pediculus humanus corporis), and pubic lice (Pthirus pubis). All stages—egg (nit), nymph, and adult—remain on the host, completing development within days. Infestation leads to pruritus and secondary bacterial infection; body lice can vector Rickettsia prowazekii and Bartonella quintana.
Fleas are wingless, laterally compressed insects of the order Siphonaptera. Their life cycle includes egg, larva, puparium, and adult. Larvae feed on organic debris, while adults require a blood meal from mammals or birds. Jumping ability derives from a resilient resilin pad that stores elastic energy. Fleas transmit Yersinia pestis, murine typhus, and tapeworms. Control strategies combine host treatment, environmental sanitation, and insecticidal applications.
Key characteristics of these ectoparasites:
- Feeding mechanism: piercing‑sucking mouthparts (ticks, bugs, lice, fleas)
- Host dependence: obligate (lice, fleas) vs. facultative (bugs, some ticks)
- Disease vector potential: high in ticks and fleas; moderate in lice; variable in bugs
- Control measures: chemical acaricides/insecticides, environmental management, host grooming.