Topic 20

Question 1

Interested in 2 questions

Answer 1

• do predators reduce the size of prey populations

- do predator prey interactions cause populations to fluctuate

Question 2

Lynx show such a preference for ..

Answer 2

showshoe hares that they make a good natural model for a simple predator prey interaction

Question 3

Hudson bay company takes..

Answer 3

yearly data on the number of lynx and hare furs harvested by trappers.

Question 4

Lynx and hare species related ..

Answer 4

largely, regular cycles. N of predator and grey societies are synchronized. predator N trailed prey N by 1-2 years

Question 5

Lotka Volterra Model

Answer 5

1920, foundation for understanding predator prey populations oscillations. diff equation express the rate of non linear growth of both predator and prey poulations

Question 6

Predator populations =

Answer 6

P

Question 7

Prey popultions =

Answer 7

H

Question 8

Lotka Volterra model is an elaboration of the ..

Answer 8

logistic equation

Question 9

Underlying principle of lotka volterra model

Answer 9

population sizes of predates and prey are linked through the density dependent influences each species has on the others birth and death rates

Question 10

Prey death rates are..

Answer 10

influenced by the size of the predator population

Question 11

Predator birth rates are..

Answer 11

influenced by the size of the prey population

Question 12

Isocline

Answer 12

line of no growth of prey or predator population (dH/dt=0)

Question 13

Predators exert a ..

Answer 13

selective pressure on prey species. produces smarter, more agile, faster better prey

Question 14

Predators must capture..

Answer 14

prey or they won’t survive. produces smarter, more agile, faster better predators

Question 15

Predator and prey are in an ..

Answer 15

arms race with prey one step ahead of predators to avoid going extinct

Question 16

Red queen hypothesis

Answer 16

co evolutionary arms race, prey faces an ever adapting predator. the predator faces an every adapting prey. have to run in order to stay in the same place

Question 17

The presence of predators can..

Answer 17

• reduce prey foraging time
• modify foraging behaviour
• induce stress responses in prey

Question 18

Prey adaptations

Answer 18

• detect predators
• avoid being seen
• prevent attack
• escape once attacked

Question 19

Detect predators

Answer 19

alarm calling/signalling. warnings of wastes effort to predator. stotting/pronking of antelope. ground mole

Question 20

Avoid being seen

Answer 20

hiding or remaining still. engaging in risky behaviours at different times of day. camouflage. octopus** leaf tailed geckos adapt to which environment they were born in

Question 21

Prevent attack

Answer 21

• make self unpalatable (hedgehog/turtles).
• aposematic* bright colouration (poison frogs)
• mimicry (coral snake vs same coloured snake)
• startle displays (fake eyes to startle, try to look larger)
• social defence (larger groups intimidating)
• tail flagging in ground squirrels
• broken leg display killdeer (protect young)
• lizard push ups

Question 22

Escape once attacked

Answer 22

• produce noxious chemicals (skunks, bomb deer beetle)
• produce a distraction (squid octopus with ink, sea cucumber)
• play dead (snake produced rotting smell)

Question 23

Herbivory is district from…

Answer 23

carnivory (typically do not kill the plants they eat)

Question 24

Herbivory

Answer 24

remove leaf, bark, stems, roots, sap and seeds. influences a plants ability to grow, survive and reproduce.

Question 25

Herbivores tend to prefer..

Answer 25

young tissue because lower quantities of structure; components that are hard to digest

Question 26

Plants are sessile and cannot run/escape but avoid predation through..

Answer 26

adaptations that discourage selection by herbivores.

Question 27

Physical deterrents of plants

Answer 27

spines or thorns, thicker wax coating, sticky hairs

Question 28

Chemical deterrents of plants

Answer 28

lemons, morphine, tomato family plants can be poisonous, rosemary, chrysanthemum (insect repellent), hog weed (burns skin)

Question 29

Behavioural deterrents of plants (part of life history)

Answer 29

oak trees produce chemical that spends through environment and attracts predators of its predator. plants produce bundle of nutrients to attract predator then gets colonized and uses that as protection. encourage herbivory for seed dispersal (corn) (pollination)

Question 30

By the tenets of coevolution strategies are a direct result of..

Answer 30

prey selection pressures

Question 31

As prey have evolved effective defences, predators have developed..

Answer 31

effective hunting methods

Question 32

3 generalized hunting methods

Answer 32

- ambush - stalking - pursuit

Question 33

Ambush

Answer 33

low frequency of success but minimal energy spent

Question 34

Stalking

Answer 34

high search time but short pursuit time (lynx)

Question 35

Pursuit

Answer 35

low search time but extended pursuit time (wolves, lions)

Question 36

Predators may use adaptations to aid in their capture of prey

Answer 36

- cryptic coloration to avoid detection or blue their outlines - aggressive mimicry to resemble their prey - cooperative behaviour to take down larger prey - chemical attacks like poisons and toxins to debilitate or kill prey (komoto dragon toxic bacteria)

Question 37

Garter snake coevolution

Answer 37

tolerates tetrodotoxin produced by the rough skinned newt,

Question 38

Beetles coevolution

Answer 38

disarm explosive capabilities of some tropical plants,