Transcript Chapter 16 Parasitism and Mutualism

Chapter 16 Parasitism and
Mutualism
types, modes of transmission
coevolutionary relationships
population regulation
Coevolution and symbiosis
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Evolution in response to interaction w/
another species
Prey defenses response to hunting
efficiency
Closer between parasites and their hosts
during symbiosis=relationship
Parasites
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2 organisms together with one deriving
nourishment at the expense of the other
Can result in disease
Microparasites
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Viruses, Bacteria, and Protozoa
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Small in size
Short generation time
Multiply rapidly in the host
Produce immunity
Spread by direct transmission
Assoc. w/ dense population of host
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Worms, lice, ticks, fleas, rusts, fungi
Macroparasites
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Worms, lice, ticks, fleas, rusts, fungi
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Longer generation time
Rarely multiply directly on host
Persist w/ continual reinfection
Spread by both direct and indirect
transmission
Challenges to the relationship
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Parasite and host
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Specialty sites on the host
Gaining entrance and escape from the host
Transmission between hosts by other
organisms- vectors
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Or intermediate hosts- often feeding related
Definitive host – intermediate - definitive
Definitive host – intermediate - definitive
Beneficial relationships
Host response
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Behavioral changes
Inflammatory
Activation of the immune system
Reduced host reproduction
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2nd factors
Mortality
 Fecundity reduced
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Mutual tolerance
Regulation of host populations
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After the initial introduction
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Mortality can spread to eventual extinction
or
Mutualism can develop after immune
response
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Dependent on reciprocal relationship
Terms to consider
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Obligatory – necessary to every exchange
or life stage or means of surviving
Facultative – can be switched to
alternative route or means given an
advantage
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Facilitative, increasing the fitness
Symbiotic mutualisms
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Involved in uptake of nutrients in both
animals and plants
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Chambers in ruminants stomach
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Nitrogen fixing bacteria
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Bacteria and protozoa/ fermentation
In plant root nodules
Fungi for mycorrhizal associations
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In plant roots
Nutrient transfer- mutualism
Range of mutualistic relationships
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Not all mutualistic are symbiotic
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Pollination of flowering plants
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Structures designed to avoid waste of pollen
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Optimizes or imparts a benefit
Seed dispersal
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Place seeds inside a delicious or attractive fruiting
body
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Survive the ride and still leave a deposit
Geographic range/
interdependence