exam 4 Flashcards
coevolution
evolution of 2 species in which each species acts as a selective pressure on the other. evolutionary change in 1 bring out evolutionary change in the other
red queen hypothesis
interactions among species are a fundamental driver of evolution
a change in one is likely to select for change in another
negative frequency dependent selection
rare variants slected
trypanosoma brucei (african sleeping sickness) steps (5)
- tsetse fly feeds on human and transfers metacyclic trypomastigotes
- transform into slender typomastigotes and multiply in blood, lymph, spinal fluid
- some turn into trypomastigotes
- tsetse fly ingests stumpy trypomstigotes
- go through transformations and multiply, goes to salivary gland and sexually reproduce to form metacyclic trypomastigotoes
what does tsetse fly trasnsmit
trypanosoma brucei (african sleeping sickness)
tsetse fly steps 5
- male and female feed on blood
- one egg develops at a time
- larva emerges and feeds on milk, second egg starts to develop
- larva passed into soil, forms hard protective coat (puparium)
- puparium turns into fly
trypanoma cruzi (chagas) steps 4
- triatomine takes blood meal and transfers metacyclic trypomatigotes in bite or mucus membranes
- amastigoes multiply in cytoplasm of infected tissue and burst out of cell and enter bloodstream or make new infection site
- triatomine ingests trypomastigoes and migrate to midgut and reproduce
- sexual reproduction, move to hindgut as metacyclic trypomatigotes
what does triatominae (kissing bug) transmit
trypanosoma cruzi (chagas)
leishamania steps (5)
- sand fly takes blood meal and injects promastigotes
- macrophages consume promastigotes and they become amstigotoes
- amastigotes rupture macrophage and get reeaten to continue cycle
- sandfly takes blood meal
- transform and sexually reproduce to promastigotes
sand fly steps 3
- females take blood meal and lay eggs
- larva hatch and form matchstick hairs, molts
- pupa molts and becomes adult
onchocerca volvulus (onchocerciasis) (river blindness) steps 5
-black fly takes blood meal and transmits L3 larvae
- migrate to subcutaneous tissue, molt + become adults, sexually reproduce
- produce unsheathed microfilaria consumed by fly
- move to thoracic muscle in fly, become L1 larvae
- molt to L2, L3, migrate to head
what does the black fly transmit
onchocerciasis (river blindness)
black fly steps 4
- females take blood meal and deposits eggs on water surface where they sink
- eggs hatch and attach to silk mat, 6-7 molts
- spins cocoon and pupates
- adults emerge from cocoon
extirpation
extinction of a population
parasite crossover
introduced nonindigenous host with nonindigenous parasite gives parasite to indigenous species
parasite spillback
introduced nonindigenous host becomes a parasite reservoir and increases indigenous host infection
parasite host hypothesis
loss of parasites during invasion of new range can give a competitive advantage
3 categories of parasite control techniques
interventions to reduce parasite transmission
anti parasitic drugs
vaccines
anisakis steps 5
- marine mammals excrete unembryonated eggs that become embryonated in water and hatch
- crustaceans ingest larva
- crustaceans eaten by fish/squid, larvae migrate to muscle tissues
- humans may eat them and become accidental hosts
- marine mammals eat fish, larva reach maturity and sexually reproduce
how did ddt work
opening sodium channels on neurons to kill insects
lipophilic, bioaccumulates at top of food chain
interferes with Ca deposition in eggs
what are pyrethroids
similar to ddt but less harmful to environment
resistance built
biological control example
purposeful introduction of an organism into a habitat in order to have a negative effect on + control a population of another organism
mosquito fish, sterile insect technique
theraputic index
toxic dose / effective dose
how do antiparasitic drugs work
target some aspect of parasite metabolism that differs from that of the host organism
likely to have some toxicity to our cells as well
