Parasitism Flashcards
What does the term degenerate mean ?
This is when parasites lack the structures and organs found in other organisms
The niche for an ectopsrasite is in the ______ of the host.Give some examples of ectoparasites…
Surface
Lice and ticks
What stage is the parasite in when host at when its in the definitive stage ….
This is the host where the parasite reaches sexual maturity
In an intermediate host ,the parasite is doing what ?
Completing its life cycle …either carrying out asexual reproduction to greatly increase its numbers or as a means of transmission,making the intermediate host a vector
What is a fundamental niche ….
One that the organisms occupies when there are no other species present competing for space or resources… This organisms will occupy the niche in abscene of interspecific competition
Explain what the competitive exclusion principle ?
This is when two species are in intense competition with one another ,the niches of the two species are so similar that the weaker of the two species will decline into extinction
Mammals have innate or natural ,__________ defence to parasites …
Non specific
Give five examples of physical barriers to parasites…..
Skin
Chemical secretions such as mucus and tears
Inflammatory response
Phagocytes
Natural killer cells ( lymphocytes- the white blood cells )
When the skin is damaged by a cut or wound,the external barrier becomes warmer and redder - state what this is a result of ….
And - how this helps a suitable defence
This is a result of small blood vessels dilating.This helps defence as it increases blood flow to the wound,thus increasing the amount of white blood cells such as phagocytes.
Describe the process of phagocytosis ….
This is a type of non specific defence where the White blood cells phagocytes engulf foreign antigens into vacuoles and digest them using digestive enzymes present in lysosomes
What type of cells carry out specific defence ?
White blood cells.These cells also carry out Immune surveillance which is when white blood cells patrol the body ,recognising and destroying foreign antigens.
What is an endoparasite ….
This is when the parasite lives within the host such as tapeworms.
What are vectors responsible for ?
Transmitting a parasite from one host to another yet may also be a host for the parasite.A good example of a vector is a mosquito transporting the malaria parasite.
State the type of niche described below …
The niche that an organism occupies when there is competition from other species.
Realised Niche
Parasites have a ________ niche
Narrow
A realised niche exists in the presence of ….
Interspecific competition
What is the definition of resource partitioning ?
When two different species compromise over resources to reduce competition.The two species manage to do exist.
Transmission is the …
Spread of a parasite to a host
What term is given to the deleterious effect that the parasite has on the host …
Virulence
What are the two conditions that result in greater transmission rates ??
Overcrowding of hosts such as in a busy place …
Means of transmission such as presence of vectors
What is the definition of the term extended phenotype ?
A theory whereby the parasites modifies the hosts behaviour to increase its own transmission.
How do phagocytes have a role in specific defence ?
As the foreign antigens previously engulfed by phagocytes are pushed back out onto the surface of the phagocyte to present these antigens to lymphocytes.
Is a lymphocytes a white blood cell ?
Yes
What is the role of B lymphocytes ?
What is the role of T lymphocytes ?
B : produce specific antibodies in response to the specific antigens
T; destroy specific infected or damaged cells by bringing about apoptosis
