Predation: Evolutionary Outcomes & Arms Races PDF

6 Predation 22 Wednesday, 8 November 2023 6 Preda(on 22 13:42 In interaction between predator and prey there are many evolutionary outcomes that can occur. ( compared to last competition lecture ) Hence these predictions are harder to make This fly here is mimicking a spider, helps evade pred...

6 Predation 22 Wednesday, 8 November 2023 6 Preda(on 22 13:42 In interaction between predator and prey there are many evolutionary outcomes that can occur. ( compared to last competition lecture ) Hence these predictions are harder to make This fly here is mimicking a spider, helps evade predation There are contrasting possibilities Theoretical ideas behind it; these are theoretical possibilities. - Technology limited - its waiting on a mutation to introduce new improvement ( technology ) of an animal. Waiting time for things to General ideas; - If a predator invests a prey needs to avoid theoretical possibilities. - Technology limited - its waiting on a mutation to introduce new improvement ( technology ) of an animal. Waiting time for things to occur. - Mutation and rate of selection limits co evolution. Leads to cycles extinction or steady states - Trade offs - all the technology is already available, no need for introduction of new mutation. But there are costs to possessing certain traits, and only do it when you really need to ( e.g., when you really need to avoid being eaten etc ) - There is then a cost benefit balance, which cycles or reaches steady state. Arms race General ideas; - If a predator invests a prey needs to avoid - If prey invests a predator need not invest as there is now an increase of prey density which offsets this cost Developing more and bigger guns between countries Comes to an end, as new technology ( submarines ) came a about. Looking at the fossil record Encephalisation quotient - how big brain is compared to body Represents distribution of encephalisation quotient of organism Ratio of bone sizes. Linked to running speed. ms through time Ratio of bone sizes. Linked to running speed. Solid lines are herbivorous and the other marks are carnivor Arms race? - carnivores aren't changing, but the ungulates ( h Looks like the general principle before that the prey increase are now more prey about Change in abundance of certain creatures Creatures that predate on other animals that have shells,e.g crabs a Shell breakers increases, See avoidance strategy increase - burrowers In shelled animals, get decline in creatures with weak she Cephalopod become more coiled res herbivore, solid lines ) are changing. e and the predators don't need to as there are shell breaking ell design See avoidance strategy increase - burrowers In shelled animals, get decline in creatures with weak she Cephalopod become more coiled Geographic mosaic of co evolution Co evolution takes place in isolated populations Intensity of interaction between populations ( predator and prey ) v Could be intense and cause co evolution or more relaxed causing ev ell design varying on local circumstances. volution in one direction Snake eats newt Tetrodotoxin TTX in humans cause paralysis and can cause comas, and Individ Tetrodotoxin TTX in humans cause paralysis and can cause comas, and Individ The newt has TTX sequestered in their body in their skin, In one newt can kill thousands of white mice, very toxic. How toxic they are varies a lot between populations Action is slowing down action potentials Different snake populations and how their action potential cha Some are much more resistant than other populations There are also protein variation, in the snakes Very strong correlation of resistance of snakes and toxicity of new dual can recover anges with increasing TTX conc wts, they go hand in hand. Distribution of resistance Resistance exists but hasn’t spread into all places. Must be reasons as to why haven't adopted it - trade offs Trade offs here Speed of snakes after ttx injection Being resistant means you lose speed relatively when you experie Fast snakes lose more speed than slow snakes There are variations of technology in different areas Different protein structure in between different areas ence poising event. There are variations of technology in different areas Different protein structure in between different areas Pacific northwest and California No cost in pacific northwest, but in cali, being resistant means yo Details been cloned to xenopus eggs and see between different populations there are different action potential effects. ou are slower Bat and moth arms race The sequence of events isn't always obvious and may not alway ys be an arms race Sometime In evolution bats evolved sonar, probably first to find wa Bats give out clicks and use returning waves to navigate themselves Moths have appeared to have responded. ay around, then for hunting. s and identify prey Moths have appeared to have responded. They are fluffy - effective way to absorb ultrasound from bats Experimental test of it is to rub coating off moths, And look at how it changes reflect sound Yellow curve is intact moth, blue with tegula removed, red with a all fluff removed Gives huge affect at how much sound moths reflect, but tiny affe Suggests evolution to conceal themselves They have also evolved sound sensitive cells all across body. Sac like organ that is sensitive to sound waves. Gives it possibility to respond to ultrasound from bats. ect in butterflies Certain moths can evade the bats, they can turn more rapidly. If ba consume moth at can't turn fast enough it can't How did bats respond to this? To the moths Stealth sonar, produce sonar but at much lower volumes Moths detect the bats at a much closer distance and is much hard Bats developed beam broadening, they spray out sound, like a shotg range of areas, so if moth turns they don't lose sight of it der to evade gun not a sniper so can detect wide Lots of different moths - very diverse Some of variations have evolved in response to bat predation Top left moth - is aposematic, ( repelling colour ) and ma Below that is okay to eat, but mimics the moth above wit Below that ( black one ) - also can't eat, also mimics Bottom one - produces massive wall of sound, jammin akes a harsh noise to put bats off them th sound itn produces s this sound ng the sonar of bats Bottom one - produces massive wall of sound, jammin On top of slide there are predictions of models - expose bats t Predict that if moth is control moth - bats will just eat it no But if you give loud jamming of sound ( can also be seen as away ), expect bats to initially have low success but then g If it was just pure jamming without startle they stay bad If there is a warning signal - they may begin eating moths b Experiments of different moths basically Did so with 2 different bat species, red bat is better at learnin ng the sonar of bats to different treatments and see response ormally s startling the bat with the sound to get get better as it gets used to sound but eventually learn to avoid ng Did so with 2 different bat species, red bat is better at learnin Bats have buzz when they get close called terminal buzz Normally just regular clicking and then has approach phase and te The moth does clicking to prevent this terminal buzz approach cat ng erminao buzz tching so bats never catch them really Other moths do different things m Many grew big tails, thought was sexually selected but is actua Deflect attention of bat from body of moth and concentrate ally anti bat e on tail