Unit 2: Organisms and evolution KA 2.4: Sex and Behaviour

Question 1

benefits of internal fertilisation (4)

Answer 1

-protection, egg is less vulnerable
-higher chance of fertilisation
-fewer eggs needed
-higher offspring survival rate

Question 2

cons of internal fertilisation (2)

Answer 2

-a mate must be located, which requires energy consumption
-requires direct transfer of gametes from one partner to another

Question 3

benefits of external fertilisation (1)

Answer 3

-potential for large amount of offspring to be produced

Question 4

cons of external fertilisation (3)

Answer 4

-many gametes predated or not fertilised
-none or limited parental care
-few offspring survive

Question 5

age of maturation in K selected species compared to r selected

Answer 5

older age

Question 6

breeding frequency in K selected species compared to r selected

Answer 6

reproduce slower

Question 7

number of offspring in K selected species compared to r selected

Answer 7

few offspring are produced

Question 8

size of offspring in K selected species compared to r selected

Answer 8

offspring are usually larger

Question 9

mortality rates in K selected species compared to r selected

Answer 9

mortality rates are generally low as most offspring survive

Question 10

level of parental care in in K selected species compared to r selected

Answer 10

higher level oof parental care

Question 11

type of environment which favours k selected specues

Answer 11

stable environments

Question 12

type of environment that favours r selected species more

Answer 12

unstable environments where the reproductive capacity has not been reached

Question 13

what is the mating of a pair of animals to the exclusion of all others called

Answer 13

monogamy

Question 14

what is it called when individuals have more that one mate

Answer 14

polygamy

Question 15

what is polygyny

Answer 15

one male mates exclusively with a group of females

Question 16

what is polyandry

Answer 16

one female mates with a number of males in the same breeding season

Question 17

what is a sign stimulus

Answer 17

a trigger that provokes a behavioural response

Question 18

what is a fixed action pattern

Answer 18

an instinctive behavioural sequence that is relatively invariant within the species and almost inevitably runs to completion

fixed action patterns are a series of sign stimuli followed by a response

Question 19

define the term honest signal

Answer 19

honest signals can indicate favourable alleles that increase the chances of survival of offspring (fitness) or a low parasite burden indicating a healthy individual

Question 20

describe how male-male rivalry can effect access to females

Answer 20

large size or weaponry increases access to females through conflict (real or ritualised)

Question 21

define sexual selection

Answer 21

sexual selection selects for characteristics that have little to benefit other that to increase chance of reproduction

Question 22

what is female choice

Answer 22

the female assesses the honest signals from each displaying male.

by assessing the honest signals of the male, the improves her own fitness and reproductive success by ensuring her offspring will have favourable alleles and so a higher fitness