Unit 2 - section 4

Question 1

Compare sperm and eggs

Answer 1

Sperm smaller and more numerous

Eggs have larger food store and are a greater energy investment

Question 2

Which gamete requires the most parental investment?

Answer 2

Eggs

Question 3

What is the problem faced by sessile organisms in terms of sex?

Answer 3

Not able to move together to mate

Question 4

Examples of how sessile organisms over come not being able to move to mate

Answer 4

Barnacles - hermaphroditic, long penis extends to next barnacle abc swaps sperm

Coral - eggs and sperm released simultaneously into water

Flowering plants - pollination, insects gametes from one flowering plant to another

Question 5

What are the costs and benefits of external fertilisation?

Answer 5

Costs
Energy used to produce lots of gametes
High mortality rate of gametes
Timing difficult although use day length and chemical signals

Benefits
Little energy investment in parental care
Good survival numbers due to large number of gametes produced

Question 6

What are the costs and benefits of internal fertilisation?

Answer 6

Costs
More energy invested per egg produced
Lot of energy invested in parental care
Protection must be given to developing embryos

Benefits
Fewer egg cells are produced
High rate of reproductive success
Low mortality rate of offspring

Question 7

What is parental care?

Answer 7

The energy parents invest into the survival of their offspring

Question 8

Why do animals invest energy in parental care?

Answer 8

It increases the probability of production and survival of young

Question 9

Describe R-selected parental care

Answer 9

Develop rapidly 
Smaller in size as an adult
Many small offspring 
Have a short generation time 
Example fish

Question 10

Describe K-selected parental care

Answer 10

Develop slowly 
Larger in size as an adult 
Few large offspring 
Have long generation time
Example elephants

Question 11

What are the restrictions with the terms K-selected and R-selected?

Answer 11

Many organisms are difficult to place into distinct groups
Trees live for a long time but produce massive numbers of offspring mammalian males R-type whereas females tend to be K-type

Question 12

How have reproductive strategies evolved and what is the premise optimal reproduction is based on?

Answer 12

Have evolved to maximise reproductive success

Optimal reproduction is based on the premise of a trade off in terms of the number and quality of current offspring versus potential future offspring

Question 13

What is polygamy?

Answer 13

Promiscuous short-lived interactions for the purpose of reproducing

Question 14

What is monogamy?

Answer 14

Having long term reactions with one partner

Question 15

What is sexual dimorphism?

Answer 15

When males and females look distinctly different

Question 16

What is the cause of sexual dimorphism?

Answer 16

Sexual selection

Question 17

What are the two ways males can gain access to females?

Answer 17

Male-male rivalry: use their strength, size or other characteristics to beat other males and impress females

Sneaking: sneak past dominant male to mate with female

Question 18

Compare the markings, structure and behaviours of males to females

Answer 18

Females are usually more inconspicuous than males

Males will display behaviour to try and attract a mate eg have a tidy nest

Question 19

What is female choice?

Answer 19

The female assesses honest signals of the fitness of males

Question 20

What are two ways fitness can be assessed on males?

Answer 20

Parasite abundance

Good genes

Question 21

Describe how leaking species uses alternative strategies for successful reproduction

Answer 21

It is common in species where male only provide sperm
Males display at a lek and the females choose from the displaying males
Satellite males may try and sneak a chance at reproducing rather than face aggression

Question 22

What is reversed sexual dimorphism?

Answer 22

When the female is larger and more conspicuous than the male

Occurs when males have large distances to travel so it makes sense for the to be smaller in terms of energy expenses

Question 23

What is species specific sign stimuli?

Answer 23

Animals often use signals that only other members of the same species understand to signal they are ready to mate. It ensures animals are most fertile when they mate improving reproductive success

Question 24

What is the role of fixed action pattern responses?

Answer 24

They attract females and can entice aggression in other males. They increase fitness by increasing the chance of successful mating

Question 25

What is imprinting?

Answer 25

An irreversible, rapid developmental process in young birds where they fixate on a large object and expect protection from it. It may impact their mating choice later in life