2.4a Parental Investment

Question 1

Males egg production: number and energy store

Answer 1

large number of gametes produced, and small energy store.

Question 2

Females egg production: number and energy store

Answer 2

small number of gametes produced, and large energy store.

Question 3

Female investment

Answer 3

Usually more females who invest more parental investment in most species.

Females also have investment in the egg structure in non-mammals or in the uterus and during gestation in mammals.

Question 4

What does parental Investment increase?

Answer 4

Parental investment is costly but increases the probability of production and survival of young.

Question 5

Classification of parenting

Answer 5

r (little) to k (lots), it is based on the level of parental investment in offspring and number of offspring produced.

Question 6

Characteristics of r-selected species

Answer 6

smaller;

have a shorter generation time;

mature more rapidly;

reproduce earlier in their lifetime, often only once; produce a larger number of
smaller offspring;
each of which receives only a
smaller energy input;

limited parental care;

most offspring will not reach adulthood.

Question 7

Characteristics of k-selected species

Answer 7

larger and live longer;

mature more slowly;

can reproduce many time in their lifetime;

produce relatively few, larger offspring;

high level of parental care;

many offspring have a high probability of surviving to adulthood.

Question 8

when does r-selection and k-selection occur:

Answer 8

r-selection tends to occur in unstable environments where the species has not reached its reproductive capacity, where as k-selection tends to occur in stable environments.

Question 9

External fertilizations

Answer 9

benefits: very large numbers of offspring can be produced

Costs: many gametes predated or not fertilized; no or limited parental care; few offspring survive.

Question 10

Internal fertilizations

Answer 10

Benefits: increased chance of successful fertilisation; fewer eggs needed; offspring can be retained internally for protection an/or development; higher offspring survival rate

costs: a mate must be located which requires energy expenditure; requires direct transfer of gametes from one partner to another.