1.
Predation
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In an ecosystem, predation is a biological interaction where a predator feeds on its prey. Predators may or may not kill their prey prior to feeding on it, but the act of predation often results in the death of the prey, thus predation is often, though not always, carnivory. Other categories of consumption are herbivory, fungivory, and detritivory, all of these are consumer-resource systems. It can often be difficult to separate various types of feeding behaviors. For example, some parasites prey on their host and then lay their eggs on it, for their offspring to feed on it while it continues to live, the key characteristic of predation is the predators direct impact on the prey population. Selective pressures imposed on one another leads to an evolutionary arms race between prey and predator, resulting in various antipredator adaptations. Ways of classifying predation include grouping by trophic level or diet, by specialization, Predators can be classified by their interactions with their prey. Two factors are considered here, how close the predator and prey are, and whether the prey is killed by the predator. A true predator is one that kills and eats another living thing, Predators may hunt actively for prey in pursuit predation, or sit and wait for prey to approach within striking distance, as in ambush predators. Some predation entails venom that subdues a prey before the predator ingests it, as in the box jellyfish, or disables it, in some cases, the venom contributes to the digestion of the prey, as in rattlesnakes and some spiders. In contrast, baleen whales eat millions of microscopic plankton at once, seed and egg predation are true predation, as seeds and eggs are potential organisms. Predators need not eat prey entirely, for example, some predators cannot digest bones, some may eat only part of an organism, but still consistently cause its death. Grazing organisms do not often kill their prey, while some herbivores like zooplankton live on unicellular phytoplankton and therefore, by the individualized nature of the organism, kill their prey, many others only eat a small part of the plant. Grazing livestock may pull some grass out at the roots, but most is simply grazed upon, kelp is frequently grazed in subtidal kelp forests, but regrows at the base of the blade continuously to cope with browsing pressure. Animals may also be grazed upon, female mosquitos land on hosts briefly to gain sufficient proteins for the development of their offspring, starfish may be grazed on, being capable of regenerating lost arms. Parasites can at times be difficult to distinguish from grazers and their feeding behavior is similar in many ways, however they are noted for their close association with their host species. This close living arrangement may be described by the symbiosis, living together. Parasitic organisms range from the mistletoe, a parasitic plant
2.
Mousetrap
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A mousetrap is a specialised type of animal trap designed primarily to catch mice, however, it may also trap other small animals. Mousetraps are usually set in a location where there is a suspected infestation of rodents. Larger traps are designed to other species of animals, such as rats, squirrels, other small rodents. The trap that is credited as the first patented lethal mousetrap was a set of spring-loaded and it was patented on 4 November 1879 by James M. Keep of New York, US patent 221,320, from the patent description, it is clear that this is not the first mousetrap of this type, but the patent is for this simplified, easy to manufacture, design. It is the industrial age development of the trap. The jaws of this type are operated by a coiled spring, the trip snaps the jaws shut, killing the rodent. Lightweight traps of this style are now constructed from plastic and these traps do not have a powerful snap like other types. They are safer for the fingers of the person setting them than other lethal traps, the classic spring-loaded mousetrap was first patented by William C. Hooker of Abingdon, Illinois, who received US patent 528671 for his design in 1894. A British inventor, James Henry Atkinson, patented a similar trap called the Little Nipper in 1898, including variations that had a weight-activated treadle as the trip. In 1899, Atkinson patented a modification of his design that transformed it from a trap that goes off by a step on the treadle into one that goes off by a pull on the bait. The similarity of the design with Hookers of 1894 may have contributed to a common mistake of giving priority to Atkinson. It is a device with a heavily spring-loaded bar and a trip to release it. Cheese may be placed on the trip as bait, but other such as oats, chocolate, bread, meat, butter. The spring-loaded bar swings down rapidly and with force when anything, usually a mouse. The design is such that the neck or spinal cord will be broken, or its ribs or skull crushed. The trap can be held over a bin and the dead mouse released into it by pulling the bar, in the case of rats, which are much larger than mice, a much larger version of the same type of trap is used to kill them. Some spring mousetraps have an extended trip
3.
Fishing bait
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Fishing bait is any substance used to attract and catch fish, e. g. on the end of a fishing hook, or inside a fish trap. Traditionally, nightcrawlers, insects, and smaller fish have been used for this purpose. Fishermen have also begun using plastic bait and more recently, electronic lures, studies show that natural baits like croaker and shrimp are more recognized by the fish and are more readily accepted. Which of the various techniques a fisher may choose is dictated mainly by the target species, bait can be separated into two main categories, artificial baits and natural baits. Using lures is a method for catching predatory fish. Lures are artificial baits designed to resemble the appearance and/or the movement of prey, the lure may require a specialised presentation to impart an enticing action as, for example, in fly fishing. A common way to fish a soft plastic worm is the Texas Rig, the natural bait angler, with few exceptions, will use a common prey species of the fish as an attractant. The natural bait used may be alive or dead, common natural baits include worms, leeches, minnows, frogs, salamanders, and insects. Natural baits are effective due to the texture, odour and colour of the bait presented. Cheese has been known to be a very successful due to its strong smell. The common earthworm is a bait for fresh water angling. Grubs and maggots are also excellent bait when trout fishing, grasshoppers, bees and even ants are also used as bait for trout in their season, although many anglers believe that trout or salmon and many other fresh water fish roe is superior to any other bait. In lakes in southern climates such as Florida, United States, bread bait is a small amount of bread, often moistened by saliva, balled up to a small size that is bite size to small fish. Most common earthworm species, such as Lumbricus terrestris, which can often be dug up in the garden, are suitable for freshwater fishing. However, on a scale they are not really candidates for worm farming for providing fishing bait. The greyish brown common earthworms are deep burrowing and do not readily breed in the shallow worm farm bins, the red compost worms, such as the well known red wiggler or the exotic European nightcrawler, are better candidates, as they are epigeic or surface dwellers. This is the reason that red worms are usually available commercially for bait worms. Their natural home is just below the surface in rotting leaves, dung heaps and they are called detritivourous because they eat detritus
4.
Fish
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A fish is any member of a group of animals that consist of all gill-bearing aquatic craniate animals that lack limbs with digits. They form a group to the tunicates, together forming the olfactores. Included in this definition are the living hagfish, lampreys, and cartilaginous, tetrapods emerged within lobe-finned fishes, so cladistically they are fish as well. However, traditionally fish are rendered obsolete or paraphyletic by excluding the tetrapods, because in this manner the term fish is defined negatively as a paraphyletic group, it is not considered a formal taxonomic grouping in systematic biology. The traditional term pisces is considered a typological, but not a phylogenetic classification, the earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts, fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Many fish of the Paleozoic developed external armor that protected them from predators, the first fish with jaws appeared in the Silurian period, after which many became formidable marine predators rather than just the prey of arthropods. Fish are abundant in most bodies of water and they can be found in nearly all aquatic environments, from high mountain streams to the abyssal and even hadal depths of the deepest oceans. With 33,100 described species, fish exhibit greater species diversity than any group of vertebrates. Fish are an important resource for humans worldwide, especially as food, commercial and subsistence fishers hunt fish in wild fisheries or farm them in ponds or in cages in the ocean. They are also caught by fishers, kept as pets, raised by fishkeepers. Fish have had a role in culture through the ages, serving as deities, religious symbols, fish do not represent a monophyletic group, and therefore the evolution of fish is not studied as a single event. Early fish from the record are represented by a group of small, jawless. Jawless fish lineages are mostly extinct, an extant clade, the lampreys may approximate ancient pre-jawed fish. The first jaws are found in Placodermi fossils, the diversity of jawed vertebrates may indicate the evolutionary advantage of a jawed mouth. It is unclear if the advantage of a hinged jaw is greater biting force, improved respiration, fish may have evolved from a creature similar to a coral-like sea squirt, whose larvae resemble primitive fish in important ways. The first ancestors of fish may have kept the form into adulthood. Fish are a group, that is, any clade containing all fish also contains the tetrapods
5.
Myxobolus cerebralis
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Myxobolus cerebralis is a myxosporean parasite of salmonids that causes whirling disease in farmed salmon and trout and also in wild fish populations. It was first described in rainbow trout in Germany a century ago, but its range has spread and it has appeared in most of Europe, in the 1980s, M. cerebralis was found to require a tubificid oligochaete to complete its life cycle. The parasite infects its hosts with its cells after piercing them with polar filaments ejected from nematocyst-like capsules, Whirling disease afflicts juvenile fish and causes skeletal deformation and neurological damage. Fish whirl forward in an awkward, corkscrew-like pattern instead of swimming normally, find feeding difficult, the mortality rate is high for fingerlings, up to 90% of infected populations, and those that do survive are deformed by the parasites residing in their cartilage and bone. They act as a reservoir for the parasite, which is released into water following the fishs death, M. cerebralis is one of the most economically important myxozoans in fish, as well as one of the most pathogenic. It was the first myxosporean whose pathology and symptoms were described scientifically, the parasite is not transmissible to humans. The taxonomy and naming of both M. cerebralis, and of myxozoans in general, have complicated histories and it was originally thought to infect fish brains and nervous systems, though it soon was found to primarily infect cartilage and skeletal tissue. Attempts to change the name to Myxobolus chondrophagus, which would more accurately describe the organism, similarly, other actinosporeans were folded into the life cycles of various myxosporeans. Today, the myxozoans, previously thought to be protozoans, are considered animals by most scientists. Recent molecular studies suggest they are related to Bilateria or Cnidaria, M. cerebralis has many diverse stages ranging from single cells to relatively large spores, not all of which have been studied in detail. The stages that infect fish, called triactinomyxon spores, are made of a style that is about 150 micrometers long. A sporoplasm packet at the end of the style contains 64 germ cells surrounded by a cellular envelope, there are also three polar capsules, each of which contains a coiled polar filament between 170 and 180 µm long. Polar filaments in both stage and in the myxospore stage rapidly shoot into the body of the host. Upon contact with fish hosts and firing of the polar capsules, firstly, this sporoplasm undergoes mitosis to produce more amoeboid cells, which migrate into deeper tissue layers, to reach the cerebral cartilage. Myxospores, which develop from sporogonic cell stages inside fish hosts, are lenticular and they have a diameter of about 10 micrometers and are made of six cells. Two of these cells form polar capsules, two merge to form a binucleate sporoplasm, and two form protective valves, myxospores are infective to oligochaetes, and are found among the remains of digested fish cartilage. They are often difficult to distinguish from related species because of morphological similarities across genera, though M. cerebralis is the only myxosporean ever found in salmonid cartilage, other visually similar species may be present in the skin, nervous system, or muscle. Myxobolus cerebralis has a two-host life cycle involving a salmonid fish, so far, the only worm known to be susceptible to M. cerebralis infection is Tubifex tubifex, though what scientists currently call T. tubifex may in fact be more than one species
6.
Trout
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Trout is the common name for a number of species of freshwater fish belonging to the genera Oncorhynchus, Salmo and Salvelinus, all of the subfamily Salmoninae of the family Salmonidae. The word trout is also used as part of the name of some fish such as Cynoscion nebulosus. Trout are closely related to salmon and char, species termed salmon, a rainbow trout that spends time in the ocean is called a steelhead. Arctic char and brook trout are part of the char family, Trout are an important food source for humans and wildlife including brown bears, birds of prey such as eagles, and other animals. They are classified as oily fish, mostly, these colors and patterns form as camouflage, based on the surroundings, and will change as the fish moves to different habitats. In general trout that are about to breed have extremely intense coloration and they can look like an entirely different fish outside of spawning season. It is virtually impossible to define a color pattern as belonging to a specific breed, however, in general, wild fish are claimed to have more vivid colors. Trout have fins entirely without spines, and all of them have an adipose fin along the back. The pelvic fins sit well back on the body, on side of the anus. The swim bladder is connected to the esophagus, allowing for gulping or rapid expulsion of air, unlike many other physostome fish, trout do not use their bladder as an auxiliary device for oxygen uptake, relying solely on their gills. There are many species, and even more populations, that are isolated from each other, the trout found in the eastern United States are a good example of this. Lake trout, like brook trout, belong to the char genus, Lake trout inhabit many of the larger lakes in North America, and live much longer than rainbow trout, which have an average maximum lifespan of 7 years. Lake trout can live many decades, and can grow to more than 30 kilograms, Trout are usually found in cool, clear streams and lakes, although many of the species have anadromous strains as well. Young trout are referred to as troutlet, troutling or fry and they are distributed naturally throughout North America, northern Asia and Europe. Several species of trout were introduced to Australia and New Zealand by amateur fishing enthusiasts in the 19th century, the introduced species included brown trout from England and rainbow trout from California. The rainbow trout were a strain, generally accepted as coming from Sonoma Creek. The rainbow trout of New Zealand still show the tendency to run up rivers in winter to spawn. In Australia the rainbow trout was introduced in 1894 from New Zealand and is a popular gamefish in recreational angling
