EE Lecture 12: Coevolution Flashcards
define coevolution
reciprocal evoln - change in 1 species causes change in a 2nd species and vv
define coadaptation
reciprocal adaptation - adaptation in one species causes adaptation in another and vv
define cospeciation
speciation in one lineage causes speciation in another lineage
do cospeciation and coadaptation have to happen together
NO
what types of interspecific interactions exist
competition predation parasitism mutualism symbiosis
what is parasitism/mutualism/symbiosis an example of
interspecific interactions
what types of coadaptations are there
- character displacement
- arms race
- coevolnary cycles
what is arms race an example of
coadaptations
what is character displacement an example of
coadapatation
what two types of positive interspecific competition exist
commensalism and mutualism
what is mutualism
mutually beneficial interaction between individuals of two species (+/+ relnship)
what is commensalism
one species benefit, other is neither harmed or benefitted (0/+ relationship)
what term is used to refer to mutualism and commensalism collectively
facilitation
what is tight coevoln
1 species 1 species
what is diffuse coevoln
1 species many species
eg.plant herbivore
name some mutualisms
mycorrhizae - symbiotic associations between plant roots and various types of fungi (80% angiosperms form this)
what is cospeciation
where is it likely to happen
speciation in parallel - likely to happen between parasites and their host
how can you tell by a phylogeny that cospeciation has occured
the parasite phylogeny/endosymbiont phylogeny will mirror the host
give an example of cospeciation
pocket gophers and chewing lice
aphids and endosymbiotic bacteria
if a parasite phylogeny mirror host phylogeny, what is this an example of
cospeciation
what are pocket gophers and chewing lice an example of
cospeciation
what are aphids and endosymbiotic bacteria an example of
cospeciation
what can competition lead to
character displacement
niche partitioning
give an example of character displacement
in sticklebacks
freshwater sticklebacks invaded lakes created by retreated ice sheets
some lakes had 1 sp, others 2
lakes with 2 sp diverged into 2 forms: benthic and limnetic with different diets
what niche partitioning was involved in sticklebaction
freshwater sticklebacks invaded lakes created by glacial retreated - lakes with 2 species diverged into 2 distinct forms
benthic
limnetic form with distinct diets each
compare benthic and limnetic forms of sticklebacks
benthic forms much larger
limnetic form smaller
different diet, one eats macroinvertebrates while the other eats plankton
what has competition among sticklebacks led to
character displacement and niche partitioning
what is a trophic mutualist - give an example
trophic mutualist - mutualist receives energy or nutrients from its partner
leaf-cutter ant-fungus mutualism -> each partner feeds the other
what is the leaf-cutter ant-fungus mutualism
each partner feeds the other
mutualism
what do some mutualists have to prevent overexploitation
some mutualists have mechanisms for cheaters eg. stopping the mutualism
outline an ant plant mutualism
acacia ants lay larvae and pupae inside an acacia thorn
where may positive interactions be more prevalent
in stressful enviros
in a mutualisti interaction, how does each partner act
each partner acts in a way that serves its own ecological and evolutionary interests
give an example of diffuse coevolnary arms race with predators
shell thickness in molluscs over geological time
what is Red Queen a hypothesis for
coevolnary dynamics
outline coevoln in brood parasitism
brood parasitism by cuckoos
cuckoo adaptation: mimic colour and speckling of eggs of host species
young cuckoo ejects eggs of host, so fed by foster parents
what is an arms race
evolnary struggle between competing sets of coevolnary genes that develop adaptations and counter-adaptations, an example of positive feedback
give an example of an arms race in the evoln of virulence : myxomatosis in rabbits
myxoma ‘natural’ host is S.American rabbits
introduced rabbits to Australia but became overpopulated -therefore introduce myxy virus to kill them off
mortality of rabits increased, however so did resistance so net effect: rabbit pop now more resistnat to virus
what are coevolnary cycles due to
negative freq dependence
which genes are among the fastest evolving in humans
parasite resistance and immunity genes
what occurs in hairworm parasitism
juvenile hairworms: parasitic in insects
ADULT HAIR WORMS: need to enter water to mate, oviposit and produce infective stages, so to overcome this they make infected insects jump into water and then emerge, by the expression of phototaxis associated proteins
what effect do adult hairworms have on host
they make infected insects jump into water and emerge by expression phototaxis associated proteins
how do adult hairworms enter water to mate
cause expression of proteins involved in phototaxis in insect host, which makes them jump into water, so adult hairworms can oviposit and produce infective stages
give examples of where parasite modification of host behaviour exists
juvenile/adult hairworms in insects
toxoplasma protozoan on warmblooded animals
what are toxoplasma protozoan hosts
warm blooded animals - mainly cats
what effect do toxoplasma protozoans have on rodents
make them less fearful of cats, seek out urine marked areas by the Toxoplasma increasing dopamine levels in brain
what do Toxoplasma protozoans do
they increase dopamine levels in the brain
what is involved in making rodents less fearful of cats
toxoplasma protozoan
what is the mechanism behind toxoplama protozoan making rodents less fearful of cats
increased dopamine levels in brain
give examples of enslaver parasites
Toxoplasma protozoan ->rodents
Juvenile/Adult hairworms in insects
Cordyceps fungi on Ant
Blue butterfly larva on ant
what effect do Cordyceps fungi have on insects and spiders/ants
ant infected by spores, grow into its brain and when ready, climbs to high leaf, attaches its mandibles and the fungus is wind dispersed
where do ants infected by cordyceps fungi go
they climb to high leaf and attach their mandibles so fungus becomes wind dispersed
discuss ant/caterpillar enslaver parasites
caterpillar larvae release same pheremones as ant larvae, so smell the same therefore ants think caterpillar larvae are ant larvae, so take them into nursery and treated like ant
discuss caterpillar larvae/parasitoid (wasp) enslaver parasites
when caterpillar larvae are present in ants nursery/nest, parasitoid such as wasp comes in, releasing pheremones that make ants panic, then wasp finds caterpillar larvae and injects eggs in them, so some caterpillar larvae become wasps, others butterflies
give some examples of plant mutualisms
pollination - bird and mammal/insect/bird seed dispersal - bird/mammal/insect/ant defence - ant- acacia mycorrhiza - plant & fungus lichens - fungus and alga
give an example of a specialist symbiosis
ant and acacia plant
tree gets defence: ants produce alarm pheromones to deter herbivores and direct attack
ant get a home+nutrition from Beltian bodies - protein rich swellings on leaflets, and nectar from glands on stalks
what are Beltian bodies
protein rich swellings on acacia plants which ants live in as part of a specialist symbiosis
give some examples of animal mutualisms
gut symbionts:commensals, parasites,mutualist corals - algae and zooxanthellae leaf cutter ant fungal gardens cleaner wrasse mullerian mimicry
what does Aneura mirabilis do? what relationship does it have
PARASITIC liverwort, takes carbon from host tree via mycorrhizal network, no chlorophyll
mutualism
how are orchids pollinated in a mutualistic relationship
pollination by sexual deception in orchids
flower mimics bees species (shape.colour.scent)
bee attempts to mate with flower
picks up pollinia and transfers
no nectar or oil reward
how does pollination by sexual deception work
give example
works in orchids flower mimics bees species in shape, colour,scent bee attempts to mate with flower picks up pollinia and transfers it no nectar or oil reward
compare Batesian and Mullerian mimicry
what species can it occur in
can occur in butterflies
Batesian mimicry involves and unpalatable model, palatable mimic, whereas Mullerian mimicry involves unpalatable model AND mimic
what is Batesian mimicry
unpalatable model and palatable mimic
what is Mullerian mimicry
unpalatable model and mimic
what is most coevolution
diffuse eg. plants and herbivores, as opposed to tight
what sequencing can be used to measure our own (human) symbionts
454 Sequencing
>1 mill sequences
give an example of gut endosymbionts manipulating human behaviour
microbes may control the eating behavior of hosts through microbial manipulation of reward pathways, production of toxins that alter mood , changes to receptors including taste receptors, and hijacking of neurotransmission via the vagus nerve which is the main neural axis between the gut and the brain.
