• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Stickleback - (Gasterosteus aculeatus).

Extracts from this document...


Stickleback. (Gasterosteus aculeatus) Sticklebacks are small, bony fish that exist throughout most of the world and are known to have a wide variety of subspecies, (for example Gasterosteus aculeatus williamsoni) that have phenotypically adapted to various environmental factors. They are small fish (2-4 inches) and are characterized by a row of free dorsal fins in front of the dorsal fin combined with the absence of scales. Male sticklebacks build intricate golf ball-sized nests, which he guards aggressively. Both males and females come together for a mating rituals. Breeding typically starts between the second and third year in the spring and summer. Males start to develop a deep red coloration on their throats and a blue tint in the eyes. They establish their territories by chasing other rival males away from their nesting site. Receptive females are led back to the nest where she deposits her eggs. The eggs are immediately fertilized by the male who then chases the female away. ...read more.


The egg of this cestode has a thin walled operculum, which upon hatching, releases the larvae. The free-swimming ciliated larvae development depends on factors such as temperature where cooler temperatures result in longer duration. The larvae is ingested by a Cyclops and the ciliated epidermis is shed inside to release the newly developed procercoid. The contagion of the stickleback occurs upon ingestion of the copepod. The procercoid develops into a plerocercoid and it starts to develop segmented proglottids once inside the gut of the stickleback. Infection of the stickleback by Schistocephalus solidus can be quite high, 14 worms and can be up to 92% of the body weight or even exceed it. Schistocephalus solidus induces a number of changes in its intermediate host, the threespine stickleback. This includes phenotypic changes that may improve the host fitness for predation. Behavioral changes may also enhance the infected stickleback to become a target for a definitive bird host. Because of these changes, the chance of the parasite to reach its next life cycle increases substantially. ...read more.


At the anterior end it has a sucker which has two central large hooks surrounded by 16 smaller hooks for attachment to the host. Trichodina species is a protozoa. The genus contains as many as 200 species, most of which are parasites on aquatic invertebrares, fish and amphibian. They are characterised by the presence of rows of cilia and sclerotised "teeth" that are used to attach the organism to the host. This protozoa swims freely in the water so transmit to the host at no specific time. Tricodina occurred only in 1998 and in particularily high prevelance in 1999. It cause extensive tissue damage to the host as it feeds and can lead to suffocation of the fish. Echinorhynchus clavula and Neoechinorhynchus rutili are both acanthocephala. They have proboscis at the anterior end of the worm with hooks, Echinorhynchus clavula having up to 200 hooks, Neoechinorhynchus rutili having 18 hooks. The most noticeable difference between the sexes of acanthocephala is that of body size, the female specimen is longer than the male and differences in size and shape of the proboscis, hooks, distribution of body spines, and the presence of papillae. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Height and Weight of Pupils and other Mayfield High School investigations section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Height and Weight of Pupils and other Mayfield High School investigations essays

  1. Selective Breeding.

    Egg numbers are reported to be very high this season so risks are high, particularly as crops are somewhat backward. WBF can decimate even a well established crop if egg and levels are high enough. In high risk situation, particularly on later sown crops and where a seed treatment for

  2. "Medicine was a Battleground for the war between the sexes in the Greco-Roman World". ...

    Women (as patients or healers) did not hold enough authority within most of the forms of medicine to be cited as support for any one medical ideology. Female patients were even referred to anonymously in case histories in the Epidemics (e.g.

  1. An eating disorder is a serious disruption of a persons eating habits, it some ...

    Girls who were reported to be vomiting to control their weight, and eating habits that may be indicating an eating disorder were both more common after the 3 years of TV exposure. Before the exposure only 3% were reported to be vomiting to loose weight, which went up to 15% after 3 years.

  2. Investigation on the shape and size of limpets on a sheltered rocky shore called ...

    The bottom for about 80% of the year. The last zone is the lower shore where the top of this zone gets covered for about 80% of the year. These tidal levels are very useful as they represent different environmental conditions to which organisms must adapt in order to survive.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work