2.4 a) Sex and Behaviour - Parental Investment

Question 1

In animals, ___ are always more numerous than ___.

Answer 1

sperm, eggs

Question 2

The production of eggs (with their ___ size and ___ store) requires far more ___ ___ than sperm production.
Which sex has the greater investment?

Answer 2

large, energy, energy investment.
Females

Question 3

Aside from greater energy investment into gametes, what other investment do females have…
For non-mammals?
For mammals?

Answer 3

egg structure.
gestation/uterus

Question 4

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

Answer 4

production, survival

Question 5

Parental behaviour can be classified into two groups, based on the level of ___ ___ and number of ___ produced.
What are they?

Answer 5

parental investment, offspring.
r-selected
k-selected
(r = ribbit ribbit = frog)

Question 6

What are the six traits of r selected species?

Answer 6

1. smaller
2. short lifespan
3. limited parental care, leading to low survival rate of offspring
4. offspring mature rapidly
5. reproduce early in lifespan, often only once
6. produce lots of offspring

Question 7

What are the six traits of k selected species?

Answer 7

1. larger
2. longer lifespan
3. high level of parental care, leading to high survival rate of offspring
4. offspring mature slowly
5. reproduce later in lifespan, can reproduce many times
6. produce few, larger offspring

Question 8

r-selected species do be:
1. (smaller/larger)
2. (long/short lifespan)
3. (limited/extensive parental care)
4. (low/high offspring survival rate)
5. (mature slowly/rapidly)
6. (reproduce early/late in lifespan)
7. (reproduce only once/many times)
8. (have tons of babies/not many)

Answer 8

1. smaller
2. short lifespan
3. limited parental care
4. low offspring survival rate
5. mature more rapidly
6. reproduce early
7. reproduce only once
8. tons of babies

Question 9

r-selection tends to occur in ___ ___, where the species has not reached its ___ ___.

Answer 9

unstable environments, reproductive capacity.

Question 10

k-selection tends to occur in ___ environments.

Answer 10

stable

Question 11

Benefits of External Fertilisation… (1)

Answer 11

large number of offspring can be produced

Question 12

Costs of External Fertilisation… (2)

Answer 12

many gametes predated or not fertilised.
no parental care, so few offspring survive

Question 13

Benefits of Internal Fertilisation… (3)

Answer 13

Higher chance of successful fertilisation
fewer eggs needed
higher survival rate of offspring due to increased protection of being retained internally

Question 14

Costs of Internal Fertilisation… (2)

Answer 14

a mate must be located.
requires direct transfer of gametes