envs lecture 13 Flashcards
what are among the most compelling examples of evolution
symbiotic interactions and coevolution
what is mutualism
interaction b.w two species, an actor and a recipient, and both gain benefits from the interaction –> mutually beneficial interaction
2 examples of mutualism
shrimp gets food and grouper gets cleaned of parasites and food particles
hummingbird and flower. hummingbird gets nectar from flower, flower gets pollinated by hummingbird
how many kinds of interactions are there between species
many; continuum from one-sided benefit to full mutualism
what is commensalism
neutral benefit to actor, positive benefit to recipient
example of commensalism
army ants hunt forest for prey. antbird follows army ant and catches the prey the ants are looking for;
neutral cost to the ants
herbivory/grazing
act of an animal feeding on another organism, particularly plants
what kind of effects does herbivory/grazing have
positive effects on herbivore, negative effect on plant
what is parasitism
an actor, the parasite, gains benefits by parasitizing a recipient
who is the actor in parasitism
the parasit
what kind of effects do parasites have
negative but not fatal effects on the host
example of parasitism
ibis (bird) with 4 ectoparasitic chewing lice
what happens w/ bird and lice
parasites can have negative effects on host; eat feathers, harder for them to handle cold weather
predation
positive for the actor but super negative for prey
why is predation super negative
usually predators kill their play
example of preadation
squirrel eating seeds
competition
positive or negative effects on actor, negative effects on recipient
what kinda effects can competition have on actor
positive OR negative
what effects does competition have on recipient
negative
examples of competition
kudzu plant is overgrowing a bunch of plants and outcompeting them
predators and scavengers compete for food at a kill
amensalism
interaction that causes unintended interactions
what kinda effect does amensalism have
no effect on actor, negative effect on recipient
examples of amensalism
animals trampling off vegetation, or humans causing oil spill and birdy covered in oil
altruism
actor has a cost to its actions, these actions benefit recipient (-, +)
examples of altruism
florida scrub jays, nest cooperatively, young stay on to help parents raise siblings
what do we find when it comes to altruism
not totally costly; can benefit actors thru inclusive fitness
what is red queen hypothesis
constant change is necessary to maintain adaptedness
another definition for red queen hypothesis
increase in adaptedness in one species reduces adaptedness of other species
who came up w/ red queen hypothesis
leigh van halen
what was red queen hypothesis invoked to explain
relatively constant extinction rates seen in the fossil record
what else was red queen hypothesis invoked to explain
general advantage of sexual reproduction in allowing faster adaptation thru recombination of genes
what is the basic idea of RQH
each species has to run (evolve) as fast as it can just to stay in the same place (survive), because interacting species continue to evolve
what is RQH a way of explaining
an evolutionary arms race
what do interacting species do
continue to evolve
what is another form of evolutionary arms race
escalation
what are the enemies
competitors, predators, dangerous prey
what did Vermeij argue
enemies were the most important agents of natural selection, causing enemy-related adaptations and responses
which is more general, RQH or escalation
escalation
what does escalation explain
explains trends in adaptation
example of escalation
mesozoic marine revolution
what happened in mesozoic marine revolution
new predators (marine reptiles, bony fish, crustacean, starfish) w/ new ways of crushing or opening exoskeletons
why do we see evolution of adaptations like burrowing, spines, swimming, other defenses evolving among prey
because of mesozoic marine revolution
what happened in mesozoic to marine groups like brachiopods that evolved little
declined in the fossil record
what does character displacement do
lessens interactions
what is character displacement
evolutionary change that occurs when two similar species inhabit same environment, differentiate [if they don’t differentiate, eliminate]
what is a famous example of character displacement
galapagos finches
what is character displacement a result of
competitive interactions among sympatric species
explain character displacement in galapagos finches
two species coexist in Santa Cruz, differ more in bill depth. coexist, so they compete, and so have evolved differences in bill size b/c they each specialize in feeding on diff seed sizes
where do we see biggest difference in bill depth
where two species coexist
what are allopatric species
separate populations
what are sympatric species
coexisting populations
what do sympatric species have
greater character displacement; differ in bill size
what is mimicry
involves one species mimicking a model species to dupe a third party or the model
give an example of mimicry
mimic dupes predators into thinking it is a noxious tasting toxic butterfly, to avoid being eaten. (not actually toxic, but look similar)
what two types of mimicry do we see
Batesian mimicry, Mullerian mimicry
what is batesian mimicry
non-toxic/noxious species mimics a distasteful/noxious species (wolf in sheeps clothing)
what is mullerian mimicry
ring of toxic species mimic each other
what is coevolution
describes special set of species interactions, typically involves reciprocal selection
define coevolution
reciprocal evolutionary change in two or more species resulting from their interaction
who came up w/ coevolution
Dan Janzen
what are diff kinds of coevolutoin
gene-for-gene coevolution, specific coevolution, diffuse or guild coevolution, escape and radiate coevolution, cospeciation
what can species do
may interact for prolonged periods of evolutionary time
what can species interacting for prolonged periods of evolutionary time lead to
coevolution
what is coevolution
reciprocal genetic change in BOTH interacting species due to natural selection that each species imposes on the other
in what ways can species interact
beneficial and deleterious
what is specific coevolution
involves interaction of two species
what is diffuse coevolution
occurs when several species are involved, and their effects are not independent
what is escape-and-radiate coevolution
involves a situation where a species evolves a defense against enemies, and is enabled to radiate into diverse descendant species, to which diff enemies may later adapt
what is arms race
prolonged coevolutionary interactions between hostile species
what can persistent coevolution result in
change in sign of interaction, so mutualists become parasitic, or parasites become mutualistic
what is mutual dependancy
one species can’t survive without other
examples of mutual dependancy
pollinators, seed dispersers, vertical transmission, integration into life cycle (mitochondria, chloroplasts)
what is decreased parasite virulence
avoid killing hosts
reciprocal natural selection
cuckoos lay eggs in nests of other species so host raises their young. some cuckoos evict eggs/hatchlings of host
selects for hosts ability to detect or reject cuckoo eggs.
selects cuckoos lay eggs that mimic host eggs
what are results of coevolution
arms race, mutual dependency, decreased parasite virulence, long term evolutionary trends
what is specific coevolution
a lot of examples of symbiosis fall into this
what are most interactions in specific coevolution
polygenic
do we know the genetic basis of specific coevolution
nah
what can specific coevolution lead to
cospeciation and coextinction
example of specific coevolution
orchid bears nectar in long spur, and is pollinated by moth
another example of specific coevolution
poisonous newts have TTC to protect against predators; snakes are major predator of newts, have evolved resistance to TTX
what is newts and snakes example of
evolutionary arms race
do all snakes have resistance to newt toxins
nope; it varies
describe resistance of snakes outside of newt’s range
low resistance
what is the parasite in orchid moth model
orchid is parasite
does orchid mimic provide nectar reward to pollinator (moth)
nope
what is specific coevolution
geographic mosaic of coevolution
another example of specific coevolution
squirrels and pines
describe squirrels and pines
pinecones are adapted to resist seed eating squirrels, or are adapted for seed dispersal (for birds) when squirrels are absent
do pines in an area w/o squirrels look same as pines in area w/ squirrels
nope; some are adapted for seed dispersal, some adapted to resist squirrels
what are mutualists in pine, squirrel eample
bird and tree
why are birds and trees mutualists
cuz help each other out thru seeds and stuff
what are squirrels in this example
squirrel is seed predator
what is guild/diffuse coevolution
opportunistic mutualism; a reciprocal interaction b/w groups of similar species where benefits are general
example of guild/diffuse coevolution
vetches (flowers) have nectaries. nectaries attract ants
describe mutualism in this eample
ants protect host plants from herbivores, they get the nectaries
what are nectaries adapted for
to attract ants
did argentine ants specifically have opportunity to contribute to selection for nectar production by vetches
nope, not until they came to Cali
what is escape-and-radiate coevolution
plants under constant pressure from herbivore (or predator/parasite)
step 1 of escape-and-radiate coevolution
new mutation arises within host lineage that confers resistance to predation/parasitism (new mutation w/ resistance to predation)
step 2 of escape and radiate coevolution
resistance host lineage diversifies rapidly in absence of predation.
lineage w/ resistance is free of herbivore, and can diversify rapidly
step 3 of escape and radiate coevolution
new mutation in predator allows it to feed on previously resistant host lineages.
produces rapid herbivore diversification
what does this kind of escape-and-radiate coevolution produce
rapid bursts of diversification in plants and herbivore, but NOT cospeciation
what does escape and radiate coevolution NOT produce
cospeciation
example of escape and radiate coevolution
herbivore (caterpillar) and its host plant
who does cospeciation
figs and pollinating wasps
what are figs and wasps famous for
coevolving
how many species of figs are dependent on specific wasps
750 species
are figs fruits
no, special inflorescences
what are these figs/plants
coadapted
what are these figs/plants coadapted for
to attract and house the wasps
what do receptive figs do
produce scents specific to particular pollinator species
what is shape of ostiole specific to
head shape of particular wasp species (lock and key)
what is morphology of individual flowers specialized for
to particular wasp species
where do wasps oviposit
only in flowers w/ short styles
where do female wasps enter
via ostiole, oviposit in female flowers
what are females adapted for
flying, burrowing into figs, laying eggs in fig oocytes
what are fig wasp males suited for
boring holes and mating
what are the coadaptations
Receptive figs produce scents specific to particular pollinator species
Shape of ostiole specific to head shape of particular wasp species (lock-and-key)
Morphology of individual flowers specialized to particular wasp species
Wasps oviposit only in flowers with short styles
what do figs and pollinator wasps show a high degree of
cospeciation
what are the host (fig) and pollinator (wasp) phylogenies to each other
mirror images essentially
what do these mirror images indicate
high degree of co-speciation between them
what do mirror image tanglegrams indicate
same history
what do you see in perfect co-speciation
exact same branching pattern; can map two trees one onto another
what do most tanglegrams look like (when we see lack of cospeciation)
tangled, criss-cross
what causes lack of co-speciation
?????
what do interactions among species range from
predation to mutation
how can these interactions change
in sign and strength
what can long-term interactions cause
evolutionary trends in extinction and adaptaiton
what is coevolution
reciprocal evolutionary change in two or more species resulting from their interaction
what can coevolution do
increase or decrease amount of interaction between species
what does character displacement do
lessens interactions
what do cospeciation and vertical transmission do
show strong interactions
