Sub 6: Defence against Predation

Question 1

what is crypsis?

Answer 1

allows prey to merge into its background

Question 2

what is disruptive colouration?

Answer 2

pattern breaks up the outline of the prey so that the body shape cannot be distinguished clearly by predators

Question 3

what is aposematism?

Answer 3

aposematic organisms deter predators through the use of bold or conspicuous patterns combined with distasteful or toxic nature

Question 4

what are the two types of mimicry?

Answer 4

batesian and mullerian

Question 5

what is batesian mimicry?

Answer 5

when an edible or harmless species mimics an aposematic species in order to avoid being eaten

Question 6

why is the number of mimics usually lower than the models?

Answer 6

if the mimics became too common then the predator will not learn to avoid the aposematic colouration since the prey is usually harmless

Question 7

what is mullein mimicry?

Answer 7

two or more aposematic species convergently evolved to have the same or similar warning signals - gives each species an additional advantage as it exaggerates the warning signal

Question 8

what is grazing?

Answer 8

involves removal of only part of each prey item and their impact os damaging but not lethal, allowing regrowth to occur.

Question 9

describe the effect of low intensity grazing

Answer 9

the most competitive grass species flourish at the expense of others. few number of different species

Question 10

describe the effect of moderate intensity grazing

Answer 10

strongest competitors are kept in check so a wider variety of less vigorous species grow as well. many different species

Question 11

describe the effect of high intensity grazing

Answer 11

many species are unable to recover from frequent grazing. only the few species able to cope will survive. few number of different species

Question 12

what are basal meristems?

Answer 12

growing points on plants that are close to the ground to avoid grazing by herbivores, aerial meristems are the opposite