2l- Parental investment

Question 1

What are characteristics of a female egg gamete?

Answer 1

• bigger
• nutrient filled
• more expensive to produce
• limited in number and produced infrequently
• if fertilised, there are greater costs to the female

Question 2

There is greater investment from females than from males, what forms does this take in mammals and in non-mammals?

Answer 2

mammals- investment in the uterus and in gestation

non-mammals- investment in egg structure

Question 3

Parental investment is costly, but why is it necessary?

Answer 3

It increases the probability of production and survival of young

Question 4

What is the classification of r-selected and k-selected organisms based on?

Answer 4

Level of parental investment in offspring and number of offspring produced

Question 5

What are characteristics of r-selected species?

Answer 5

• 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 receive a smaller
  energy output)
• limited parental care
• most offspring will not reach adulthood

Question 6

What are characteristics of k-selected species?

Answer 6

• larger
• live longer
• mature more slowly
• can reproduce many times in their lifetime
• produce relatively few but larger offspring
• high level of parental care
• many offspring have a high probability of surviving to adulthood

Question 7

What are characteristics of the male sperm gamete?

Answer 7

• small
• have no nutrients
• cheap to produce
• continuously made throughout life

Question 8

Where does r-selection tend to occur?

Answer 8

In unstable environments where the species has not reached its reproductive capacity

Question 9

Where does k-selection tend to occur?

Answer 9

In stable environments

Question 10

When does internal fertilisation occur?

Answer 10

When the male and female gametes fuse inside the body

Question 11

When does external fertilisation occur?

Answer 11

When the male and female gametes fuse outside the body

Question 12

What is a benefit of external fertilisation?

Answer 12

• very large numbers of offspring can be produced

Question 13

What are some costs of external fertilisation?

Answer 13

• many gametes predated or not fertilised
• no or limited parental care
• few offspring survive

Question 14

What are some benefits of internal fertilisation?

Answer 14

• increased chances of successful fertilisation
• fewer eggs needed
• offspring can be retained internally for protection and/or development
• higher offspring survival rate

Question 15

What are some costs of internal fertilisation?

Answer 15

• a mate must be located which requires energy expenditure

- requires direct transfer of gametes from one partner to another