Topic 20 -Coevolution

Question 1

Lynx show a preference for

Answer 1

snowshoe hair, they make a good model for a simple predator prey interaction

Question 2

How did the Hudson Bay Company help model lynx and snowshoe hare

Answer 2

yearly data on the number of lynx and hare furs harvested by trappers, large regular cycles every 10 years

N of predator and prey species are highly synchronized, predator trails N by 1-2 years

Question 3

Lotka-Volterra Models (1920s)

Answer 3

foundation for understanding predator-prey population oscillations

differential equations (dN/dt) express the rate of non-linear growth of broth predator-prey populations

Question 4

P

Answer 4

Predator Population size

Question 5

H

Answer 5

prey population size

Question 6

Underlying principle of Lotka-Volterra model

Answer 6

populations sizes of predators and prey are linked through the density-dependent influences each species has on the others birth and death rates

Question 7

Natural selection can act on traits within both populations for predator in prey. Predators exert a ….

predators must….

Answer 7

selection pressure on prey species to produce better adapted prey

capture prey or they will not survive leading to better predators

Question 8

Predator and prey are in an arms race with prey…

Answer 8

one step ahead of predators to avoid going extinct

Question 9

Red Queen hypothesis

Answer 9

co-evolutionary arms race

the prey/predator faces an ever adapting predator/prey

“have to run (evolve) in order to stay in the same place”

Question 10

Prey adaptations (4)

Answer 10

Detect predators
Avoid being seen
Prevent attack
Escape once attacked

Question 11

Detect predators

Answer 11

Alarm calling/signal
warnings of wasted effort to predator
ex slotting/pronking of an antelope

Question 12

Avoid being seen

Answer 12

Hiding/remaining still

engaging in “risky” behaviours at a different time of day

camouflage

Question 13

Prevent attack (5) and 3 examples

Answer 13

make self unpalatable 
Aposematic colouration
Mimicry 
startle display
social defense 
ex tail flagging in ground squirrels 
ex broken leg display killdeer (protect young)
ex lizard push ups

Question 14

Escape once attacked

Answer 14

produce noxious chemicals
produce a distraction
play dead

Question 15

Herbivory is distinct from carnivory because

Answer 15

herbivores typically do not kill the plants they eat

can remove the bark, leaves, stems, roots, sap or seeds, influences a plants ability to grow, survive and reproduce

Question 16

herbivores tend to prefer _______ tissues -lower quantities of structural components that are hard to digest

Answer 16

young

Question 17

plants are sessile and can not run away, therefore they produce deterrents that may be

Answer 17

physical -needles
chemical -poison ivy
behavioral -release a compound that will attract a predator to the herbivore

Question 18

predators may use different adaptations to catch prey such as (4)

Answer 18

cryptic colouration to avoid detection or blur outlines from prey

aggressive mimicry to resemble prey

cooperative behavior to take down larger prey

chemical attacks like poisons and toxins to deliberate or kill prey

Question 19

examples of co evolution

Answer 19

garter snake tolerates tetrodotoxin produced by rough skinned newt

beetles that disarm explosive capabilities of tropical plants