Predation (DONE) Flashcards
Define predatory-prey interactions:
The ecological relationships & dynamics between predators & their prey
These interactions are a fundamental aspect of ecosystems - have effects on population dynamics, community structure & evolutionary processes
What are some examples of possible evolutionary outcomes of predator-prey interactions?
- Camouflage of prey = increased visual acuity of predators
- Escape speed = speed of pursuit
- Flocking & herding = counterstrategies (e.g. picking the slowest, oldest, weakest etc from the grp)
- Predator avoidance = trickery (e.g. mimicry)
What are the general predictions of predator-prey interactions?
- If predator invests –> greater avoidance by prey
- If prey invests –> predator not respond bc, e.g. prey density inc (cancels cost to predator)
What did Abrahams (2000) say about trade-offs in predator-prey interactions?
Investments by predators or prey (e.g. running speed) reduced other aspects of fitness
(e.g. thin bones break, lean bodies starve)
What is the main driver of adaptations in predator-prey interactions?
Coevolution, where adaptions in one species drive counter-adaptations in the other
What are some examples of predator prey strategies?
1 - Prey selection by predators –> Targeting the weakest (e.g. slowest or youngest individuals)
2 - Prey mimicry –> species like Rhagoletis pomonella mimic predators (e.g. spiders) to avoid being eaten
What is a coevolutionary arms race?
An escalating evolutionary process where predators & prey develop adaptations to outcompete each other
What is an example of a coevolutionary arms race?
Ungulates & carnivores
Ungulates evolved faster running speeds, forcing carnivores to improve hunting strategies & brain size
Case Study: Toxin Resistance in Newts and Snakes
How do newts protect themselves from predators?
They produce tetrodotoxin (TTX), a neurotoxin that paralyses predators by blocking sodium channels
Case Study: Toxin Resistance in Newts and Snakes
How have snakes (e.g. garter snakes) adapted to newt TTX?
- Evolved mutations in sodium channels that resist TTX
- Resistance incurs geographical trade-offs
–> Northern populations: minimal cost
–> Southern populations: reduces crawl speed due to resistance
Case Study: Toxin Resistance in Newts and Snakes
What experimental evidence links snake resistance to fitness trade-offs?
Resistant snakes exposed to TTX showed slower movement, demonstrating the cost of resistance
Case Study: Moths and Bats
What is echolocation & how to bats use it?
Echolocation involves emitting sound waves & analysing echoes to locate prey
Case Study: Moths and Bats
What are moth counter-adaptions to bat echolocation?
- Stealth coating = reduces sound reflection
- Sound detection = evolved “ears” to detect bat echolocation
- Evasive flight = faster, tighter manoeuvres to escape
- Jamming sonar = some moths emit sounds to interfere w echolocation (e.g. Trigona moths)
Case Study: Moths and Bats
How do bats counter adapt to moth defences?
1= Quieter echolocation calls (“whispering”)
2 = Modified calles for broader detection ranges
What is aposematic signalling?
Warning signals (e.g. bright colours or sounds) by unpalatable moths to deter predators
What is Batesian mimicry?
Palatable moths mimic unpalatable species to avoid predation
How do silk moths tails create sensory illusions?
Long tail streamers divert bat attacks away from vital body parts
What experimental evidence supports the role of long moth tails?
Longer tails increased the likelihood of escaping bat attacks
How does geographic variation affect coevolutionary dynamics?
Local conditions (e.g. toxin levels in newts) drive variation in predator-prey adaptations
What are cost-benefit trade-offs in predator-prey adaptations?
Adaptations like resistance or evasive flight often incur fitness costs, such as reduced speed or efficiency
How do sensory adaptations evolve in predator-prey interaction?
- Predators (e.g. bats) evolve echolocation
- Prey (e.g. moths) develop sound detection or stealth adaptations
What evidence supports coevolution between newts & snakes?
1 - Correlation between newt toxicity & snake resistance
2 - Resistance linked to mutations in sodium channels
What evidence supports bat-moth dynamics?
1 - Removing moth fluff increased sound reflection, confirming stealth function
2 - Longer moth tails resulted in more missed bat attacks
What factors influence predation escape probability?
Speed, agility & sensory countermeasures
(Need to check if this formula is actually needed)
What is the formula for fitness trade-offs in adaptations?
Fitness = B - C
Where B = survival benefits & C = cost of adaptation
Summary:
What do predator-prey interactions demonstrate?
The dynamic coevolution of species thru adaptations & counter-adaptations, driving biodiversity & ecological balance
