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Glossary of Envi Sci 114 3

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Created by jkadlik

Microparasites
small size
short generation time

viruses
bacteria
fungi
protozoans

transmission is mostly direct









Macroparasites
large size
long generation time

flatworms, roundworms, flukes
lice, fleas, ticks
fungi
dodder, broomrape, mistletoe

direct or indirect transmission- intermediates









Parasite transmission
microparasites
direct transmission

influenza airborne
smallpox direct contact
cholera water
STDs sexual interactions







Parasite transmission (macro)
macroparasites
direct transmission

endoparasites round worms
ectoparasites lice, mites, ticks, fleas
holoparasites parasitic plants






ectoparasites
on skin feathers, fur
move easily to new hosts


endoparasites
within the host
enter and leave via natural openings
travel internally to point of infection



Ectoparasite cycle
external parasites of birds & mammals

most lay eggs directly on hosts
fleas lay eggs in nests and bedding
larvae leap onto nearby hosts





Endoparasite cycle
roundworms (Ascaris)
eggs expelled with feces
swallowed by susceptible hosts
eggs hatch in intestines
larvae enter blood system and go to lungs
then to mouth –coughed up from lungs
go to stomach, mature, enter intestines
pass out to environment








HOLOPARASITES
plants that lack chlorophyll
nutrients from roots of hosts

seeds germinate
roots grow through soil
attach to roots of host plant






Intermediate Vectors
intermediate organism required

Lyme disease black-legged tick
pathogen: bacterial spirochete
Borrelia burgdorferi
tick moves pathogen from host to host






Parasites reduce...
growth and reproduction
Defense mechanisms require resources
Mutualism
relationship between members of two
species that benefits both

more reciprocal exploitation
than cooperative effort
may have evolved from host-parasite
or predator-prey interactions







SYMBIOTIC MUTUALISM
o individuals coexist and their relationship is obligatory

o at least one member depends on the other

o permanent & obligatory mutualism
results in life forms in which the
individual identities and forms of each
organism become indistinct








Lichens
fusion of mutualists

alga + fungi in a body - thallus
alga photosynthesizes - nutrients for both
fungus - shields alga from harmful light
accelerates photosynthsis
absorbs and retains water
and nutrients for both








Digestive mutualism
digestive system of herbivores
bacteria and protozoa

ruminants anaerobic fermentation
in chambers
mammals & some birds & lizards
microflora needed to
digest cellulose in plant tissues








FIXATION OF GASEOUS NITROGEN
N2 is 79% of the troposphere
biologically inert
legumes can fix N2

legume roots attract Rhizobium
bacteria in nodules reduce N2 to NH3
bacteria provide useable N to plant
plant provides C and nutrients to bacteria








PLANT ROOTS AND MYCORRHIZAL FUNGI
most terrestrial plants
in nutrient poor soils

increases uptake of water, nitrogen
and phosphorus

protects against root pathogens







ENDOMYCORRHIZAE
formed by soil fungi that invade
cortical cells of plants
no change in external appearance of root
arbuscules form
uptake of phosphorus from soil increased
increase in water and nutrient uptake
increased plant growth







ECTOMYCORRHIZAE
soil fungi invade roost and grow between
cortical cells
Hartig net formed
external fungal mantle
feeder roots changed in shape to
increase surface area
increased uptake of water & nutrients
defense against root pathogens








MUTUALISM AS A HOST DEFENSE
endophytic fungi in grasses alkaloids
tall fescue, perennial ryegrass

cleaner fish external parasite removal

birds that remove parasites from
skin of large animals







INDIRECT MUTUALISM
mutualistic relationship between
two organisms may be facilitated
by a third species

similar to vector organisms
and intermediate hosts
in parasite/host interactions







Ozone
ozone (O3) normal variable concentration gas in the troposphere

concentration x length of
exposure determines when it is
an air pollutant!





Affects of Ozone
affects visibility

affects human health

affects plant health





Ozone formation in the troposphere
nitrogen dioxide (NO2)

Sunlight required uvB region

Temperature 65F (18.3C)

some level of VOCs
natural
combustion







Sources of VOCs
combustion
cars, trucks, buses, planes
heating, power plants
evaporation gasoline, solvents
chemical manufacturing
petroleum refining
natural emissions from vegetation







OZONE FORMATION BEGINS WITH OXIDES OF NITROGEN (NOx)
o Nitric oxide NO
o NO with H2O to nitrogen dioxide
NO2
o NO2 reacts or is deposited
o new NO overnight and early in the
day converted to NO2
o Sources







Alveoli
300 million in lungs
O2 higher in alveoli, diffuses to blood
in surrounding capillaries

CO2 higher in blood, diffuses from blood
into alveoli






Inhaling Ozone
induction of respiratory symptoms

decrements in lung function

inflammation of airways





Respiratory symptoms of inhaling ozone
coughing

throat irritation

pain on deep breathing

chest tightness, shortness of breath







ozone in the respiratory tract
limited solubility in water

not removed in upper respiratory tract
reaches lower tract

dissolves in layer of epithelial
lining fluid (ELF)

throughout the conducting airways
of the lung










OZONE EFFECTS ON LUNG CELLS
ozone: no direct damage to cells

ozonides, aldehydes & hydrogen peroxide
are formed when ozone interacts with unsaturated fatty acids

they are more stable and can damage cells






LUNG INFLAMMATION
damaged epithelial cells release
inflammatory precursors
white blood cells attracted
activate alveolar macrophages
which leads to lung inflammation
antioxidants may also protect






studies to see effects of ozone on humans
animal studies

controlled human exposure studies

field & epidemiological studies





animal studies of ozone effects
Most of what we know comes from lab studies with animals

By using animals we can illustrate a fuller array of effects and exposure conditions than can be investigated in humans



HEALTH EFFECTS – CONTROLLED EXPOSURES
reduced lung function
reduced inspiration and exhalation
discomfort
rapid shallow breathing
cough and pain on breathing

inflammation and cell damage in lungs
decreases as exposure decreases








PROBLEMS WITH CONTROLLED EXPOSURE STUDIES
volunteers usually young healthy men

ozone concentrations are higher than ambient
which guarantees results

results provide no clear threshold for
the general population







POSSIBLE LONG-TERM OR PERMANENT LUNG INJURY
concern that repeated short-term damage
from ozone exposure may permanently
injure lungs

repeated impacts with children may lead to
reduced lung function as adults

accelerated lung function in normal ageing








LUNG DISEASES
ozone may aggravate chronic lung diseases
emphysema
bronchitis

animal studies indicate decrease in immune system function
possible increase in bacterial infections






AGGRAVATION OF ASTHMA
high ozone levels result in more asthma attacks

ozone increases sensitivity to allergens

dust mites
cockroach feces
pets
fungal spores, pollen








Climate change and ozone
climate change

can affect human health

by increasing summer
ozone concentrations
and temperatures







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