U2)KA5)- the parasite niche and lifecycle Flashcards
what is an ecological niche
- definition
- more detailed explanation
- an ecological niche is a multi dimensional summary of tolerances and requirements of a species
- ecological niche - attempts to summarise all factors that influence the distribution of individual species. At the simplest level is described as the role an organism plays in the living community. eg ‘woodland herbivore’
- factors that should be considered are abiotic factors (temp, ph , light intensity humidity) and biotic interactions (predator-prey interactions, competition , parasitism)
what is interspecific and intraspecific competition
interspecific - occurs between individuals of different species
intraspecific- occurs between individuals of the same species
what is the
- fundamental niche
- realised niche
- fundamental niche of a species is the set of resources that it is capable of using in the absence of any interspecific competition
- the realised niche is the set of resources that the species actually uses in response to the presence of interspecific competition
fundamental and realised niche basic definition
- a species has a fundamental niche that it occupies in the absence of any interspecific competition
- a realised niche is occupied in response to interspecific competition
explain the competitive exclusion principle
- in some cases of interspecific competition , the realised niche of the two species is so similar that one species will lose out more in the competition , so its population will decline , leading to local extinction
example of competitive exclusion principle
grey squirrels which were introduced in the UK , are able to eat seeds from deciduous trees before they are fully ripe and so are able to out compete red squirrels in these habitats
what is resource partitioning and give an example
- where two species living in a habitat have similar requirements it may be that the realised niches are sufficiently different so that they can co exist.
( resource partitioning can occur when the two species exploit different components / parts of the resource so reducing potential competition
(eg evolution of different beak lengths and foraging behaviours in waders has allowed various species to exploit food at different depths in their shared habitat)
what is symbiosis
symbiosis is co evolved and intimate relationship between 2 different species.
what is parasitism
- parasitism is a symbiotic intereaction between a parasite and its host , which can be described using a +/- /0 notation.
- the parasite benefits + in terms of nutrients at the expense - of its host
how does the parasite gain benefit in terms of nutrients at the expense of the host
what other expenses does the host have to deal with
- the parasite uses the hosts resources for growth and reproduction
- as well as losing resources the host incurs further costs in defending its tissue from parasitic attack ( technically the parasite is harmful to the host)
who’s reproductive potential is greater - the parasite or host
the reproductive potential of the parasite is greater than that of the host
- most parasite have a specialised niche as they are very ____ ______
- as the host provides so many of the parasites needs , many parasites are degenerate , what does this mean?
- host specific
- they lack the structure and organs found in other organisms
what are
- ectoparasites
- endoparasites
- ectoparasites live and feed on the surface of their host (eg ticks, lice, fleas)
- Endoparasites live within the host ( eg tapeworm , plasmodium (causes malaria) , rhinovirus (causes common cold)
some parasites require only one host to complete their life cycle. many parasitic lifecycles can involve more than one species.
what is
- definitive host
- intermediate host
- the definitive host is the organism on which or in which the parasite reaches sexual maturity and so carries out sexual reproduction
- an intermediate host is one in which developmental stages happen to complete the parasites life cycle.
what are vectors
- species in the parasite lifecycle that play an active part in the transmission of the parasite. they can also be hosts
eg the mosquito is the vector for the malarial parasite and it is also the definitive host. but vectors are not always hosts : aphids are vectors for plant viruses , but the viruses have no lifecycle stages in the aphids