Week 1 Flashcards
biosystem
two different species interact with each other over a significant period of time or the relationship is essential to at least one partner
symbiotic relationships
commensalism and mutualism
commensalism
“eating with,” one benefits and the other isn’t harmed
commensalism examples
scavengers, phoresis, honey bee mites
mutualism
both benefit
mutualism examples
intestinal lactobacillus and ciliates in rumen of ruminants
parasitism
one benefits and the other is harmed
sensu lato
broad sense, viruses, bacteria, eukaryotes
sensu stricto
strict sense, only eukaryotes, protozoa, metazoa, excluding fungi
parasitoidism
parasitoids spend long time in or on host and then kill it
parasitoids
most parasites avoid killing host because they need the host to survive, parasitoids are designed to kill the host
parasitoid examples
lampreys on freshwater fish as ectoparasitoids and killer wasps on cicadas
infection
active or passive penetration of microorganisms into the body in which they can multiply and cause diseases
infection exemption
it is not considered infection if the host doesn’t support the infectious agent
parasitology
active penetration, diseases, and infected body
parasitology: active penetration
invasion mostly
parasitology: diseases
only pathogenic organisms
parasitology: infected body
host
who is the guest?
parasites
ectoparasites
external parasites including arachnids and insects
ectoparasites: arthropods
extracellular
endoparasites
internal parasites
endoparasites: helminths
extracellular or intracellular, most extracellular
endoparasites: protozoa
extracellular or intracellular
endoparasites: arthropods
extracellular
what is the advantage of being intracellular?
hide from immune system
ectoparasites: arachnids
mites (scabies) and ticks (lone star tick)
ectoparasites: insects
fleas (dog flea), lice (head louse), mosquitoes (anopheles)
endoparasites: helminths (worms)
trematodes (sheep liver fluke), cestodes (fox tapeworm), nematodes (hookworms), acanthocephala (macranthorhynchus)
helminths: trematodes
flukes
helminths: cestodes
tapeworms
helminths: nematodes
roundworms
helminths: acanthocephala
thorny-headed worms
endoparasites: protozoa
amoebae (entamoeba), ciliates (rumen cialiate isotricha), flagellates (trypanosoma), sporozoa (toxoplasma)
Who is the host?
animals and plants
host: animal vertabrates
warmblooded animals, all kinds of parasitic groups
host: animal invertebrates
bee tracheal mites, protozoa vector function (leishmania), entomopathogenic nematodes (heterorhabditidae)
host: plants
pine beetle
potential usage of parasites
medical leeches, population control, hookworms to reduce asthma
parasitism
a form of ecological interactions
parasitism: host organism
variety in invertebrates and vertebrates, many parasites can go through multiple hosts
parasitism: infectious agent
variety of eukaryotes, including protozoa, helminths, and arthropods
comparison of related free living and parasitic species
parasitic forms show genetic reductions, loss of functional organs, new structure or adaptations to parasitic lifestyle
genetic reductions
reduced functions due to readily available resources results in smaller genome size
loss of functional organ/organelle
results in inability for certain processes due to having readily available resources like cholesterol or nucleotides
new structures or adaptations to parasitic lifestyle
enabling immune response evasion, antigenic variety, novel sense organs
free living mite vs parasitic mite
free living mite has longer legs for mobility, thicker exoskeleton for protection, and is smooth. parasitic mite has short legs, spikes to attach, and thin exoskeleton due to protection from host
divergent evolution
evolution of two or more similar species from a common anscestral stock
close taxonomic relationship but may develop different features
divergent evolution
convergent evolution
evolution of two or more similar species from unrelated forms adapted due to the same selection pressures
significant taxonomic distance but develop similar features
convergent evolution
convergent evolution example
wolf and tasmanian wolf, not related but similar features
divergent evolution example
trichomonas found in T. Rex found in several birds and reptiles today
divergent evolution is mainly in parasites
true