Predation Flashcards
What is predation?
When one species serves as a resource for the other. There are clear asymmetric benefits.
What are the four types of predatory relationships?
Predators sensu latu, herbivores, parasites and parasitoids.
What are typical characteristics of predators?
They consume the whole prey (such as carnivores, raptors, reptiles, frogs and spiders) and remove the prey from the population. The predators are often larger than their prey - except in cooperatively hunting animals such as wild dogs.
What is herbivory?
When animals eat whole plants of parts of plants, such as ungulates, plant-eating fish and many insects.
What are parasites?
Organisms that consume parts of living prey organisms. They often attach themselves to the body of their host and fully depend on a host. They typically do NOT kill their host.
What are parasitoids?
Wasps and flies whose larvae consume the tissues of living host. The larvae typically kill the host.
What is the Lotka Volterra model?
Model for predator-prey relationships.
What is C in the lotka volterra equation for prey?
Capture efficiency.
What is a in the lotka volterra equation for predator?
reproduction conversion.
What is the equation for prey population?
dN/dt = rprey V- cVP
What is the equation for predator population?
dN/dt = acVP - dP.
What is the equilibrium point in isoclines?
Where equilibrium isoclines for predator and prey cross.
Do the models agree with actual data?
Yes - the interaction is sufficient enough to generate cycling.
Why might cycles be dampened in many natural populations?
A switch to alternative preys along with life-history traits.
What was an experiment done on waders?
Waders were excluded from some patches and after 13 days the prey densities were compared between excluded and control sites.
What was found with the wader experiment?
Predators can keep prey populations below their carrying capacity - inside the exclosure prey densities increased and outside the exclosures prey densities decreased.
What happens when prey growth increases?
Predator population increases, indicating that the prey population’s size is controlled by predators.
Why might pest biological controls be better than pesticides?
Predators numbers can be kept low to allow the prey population to grow - can be used in reverse concept as well.
What are more resources associated with?
Larger size and larger reproductive output.
What is plasticity?
The adaptability of an organism to changes in its environment or differences between its various habitats.
What was found with tiger snakes on islands (large prey) and mainland tiger snakes (small prey)?
Island population have larger jaws and it was found that there is genetic differences between the two populations for larger jaw lengths.
What can be concluded from the experiments with tiger snakes?
Predator/prey relationships can impact the evolution of species.
What does natural selection favour?
Strategies that increase resources and reduce death in prey species.
What strategies reduce death in prey species?
Traits that favour hiding, escaping, warning, fighting off predators.
What is cryptic colouration?
The avoidance of detection - colour matching to background e.g. horned lizard.
What is aposematic colouration?
The passive avoidance of predators through advertisement of toxicity through colours.
What are defense traits?
Active engagement to delay or prevent attack.
What are examples of organisms that have defense traits?
Stinging caterpillar in costa rica and bombadier beetle.
What is batesian mimicry?
A harmless species resembles a harmful species.
What is mullerian mimicry?
Several harmful or unpalatable species resemble each other such as Heliconius butterflies from S america.
What is the thought purpose of Mullerian mimicry?
Believed to amplify signal and more easily elicit avoidance.
Why might oscillations in nature be dampened?
Several prey and predator populations interact.
