invasive species

Examples of invasive species in the following topics:

• The Role of Species within Communities

  • Communities are shaped by foundation species and keystone species, while invasive species disrupt the natural balance of an area.
  • These include the foundation species, keystone species, and invasive species.
  • One of the many recent proliferations of an invasive species concerns the growth of Asian carp populations.
  • Local and national politicians have weighed in on how to solve the problem, but no one knows whether the Asian carp will ultimately be considered a nuisance, like other invasive species, such as the water hyacinth and zebra mussel, or whether it will be the destroyer of the largest freshwater fishery of the world.
  • In the United States, invasive species such as (a) purple loosestrife (Lythrum salicaria) and the (b) zebra mussel (Dreissena polymorpha) threaten certain ecosystems.

• Exotic Species

  • For this reason, exotic species, also called invasive species, can threaten other species through competition for resources, predation, or disease.
  • For example, invasive plants can alter the fire regimen, nutrient cycling, and hydrology in native ecosystems.
  • Invasive species that are closely related to rare native species have the potential to hybridize with the native species.
  • Invasive species cause competition for native species.
  • Describe the impact of exotic and invasive species on native species

• Population Demography

  • In the United States, however, Asian carp is considered to be an invasive species.
  • It disrupts the structure and composition of native fish communities to the point of threatening native aquatic species.
  • The aim is to develop methods of controlling the species without damaging native fish.
  • Populations are dynamic entities, consisting of all of the species living within a specific area.
  • They fluctuate based on a number of factors: seasonal and yearly changes in the environment, natural disasters such as forest fires and volcanic eruptions, and competition for resources between and within species.

• Whole-Genome Duplication

  • In some cases a polyploid individual will have two or more complete sets of chromosomes from its own species in a condition called autopolyploidy.
  • The other form of polyploidy occurs when individuals of two different species reproduce to form a viable offspring called an allopolyploid.
  • The prefix "allo" means "other" (recall from allopatric); therefore, an allopolyploid occurs when gametes from two different species combine.
  • It has been suggested that many polyploidization events created new species, via a gain of adaptive traits, or by sexual incompatibility with their diploid counterparts.
  • An example would be the recent speciation of allopolyploid Spartina — S. anglica; the polyploid plant is so successful that it is listed as an invasive species in many regions.

• Loss of Biodiversity

  • Traditionally, ecologists have measured biodiversity, a general term for the variety of species present in the biosphere, by taking into account both the number of species and their commonness.
  • The Galápagos finches are an example of a modest adaptive radiation with 15 species.
  • The Nile perch was introduced in 1963, but was not a problem until the 1980s when its population began to surge by consuming cichlids, driving species after species to the point of extinction (the disappearance of a species).
  • The rate of species loss today is comparable to those periods of mass extinction.
  • Specifically, three human activities have a major impact: destruction of habitat, introduction of exotic invasive species, and over-harvesting.

• Habitat Loss and Sustainability

  • Other species cannot do this.
  • Remove the entire habitat within the range of a species and, unless they are one of the few species that do well in human-built environments, the species will become extinct.
  • This process may be natural or unnatural, and may be caused by habitat fragmentation, geological processes, climate change, or human activities such as the introduction of invasive species or ecosystem nutrient depletion.
  • It is home to one sub-species of orangutan, a species of critically endangered elephant, and the Sumatran tiger; however half of Sumatra's forest is now gone.
  • (a) One sub-species of orangutan is found only in the rain forests of Borneo, while the other sub-species of orangutan is found only in the rain forests of Sumatra.

• Plague

  • The reservoir commonly associated with Y. pestis is several species of rodents.
  • In the steppes, the reservoir species is believed to be principally the marmot.
  • In the United States, several species of rodents are thought to maintain Y. pestis.
  • However, the expected disease dynamics have not been found in any rodent species.
  • Y. pestis expresses the yadBC gene, which is similar to adhesins in other Yersinia species, allowing for adherence and invasion of epithelial cells.

• Pathogenicity Islands and Virulence Factors

  • Typical examples of PAIs are adherence factors, toxins, iron uptake systems, invasion factors and secretion systems.
  • They are incorporated in the genome of pathogenic organisms, but are usually absent from those nonpathogenic organisms of the same or closely related species.
  • Typical examples are adherence factors, toxins, iron uptake systems, invasion factors and secretion systems.
  • One species of bacteria may have more than one PAI (i.e. salmonella has at least five).

• Bacterial Flora

  • The large intestine houses over 700 species of bacteria , the largest bacterial ecosystem in the human body that perform a wide variety of functions.
  • An individual that depends on absorption of vitamins formed by bacteria in the large intestine may become vitamin-deficient if treated with antibiotics that inhibit other species of bacteria as well as the disease-causing bacteria.
  • These are antibodies produced by the immune system against the normal flora, that are also effective against related pathogens, thereby preventing infection or invasion.
  • Escherichia coli is one of the many species of bacteria present in the human gut.

• Pathogenicity Islands

  • They are incorporated in the genome of pathogenic organisms, but are usually absent from those nonpathogenic organisms of the same or closely related species.
  • Typical examples are adherence factors, toxins, iron uptake systems, invasion factors, and secretion systems.
  • One species of bacteria may have more than one PAI (i.e.