Sexual Reproduction

Question 1

What are the 2 phases of life

Answer 1

Vegetative - animal grows or maintains itself

Reproductive - animal engages in activity designed to replicate itself

Question 2

What is characteristic of an r species?

Answer 2

• small body size
• short lifespan
• short gestation
• large litter
• rapid rate of development
• short birth interval
• variable pop(n) size

Question 3

What is characteristic of k species?

Answer 3

• large body size
• long lifespan
• long gestation
• single offspring
• slow rate of development
• long birth interval
• stable pop(n) size

Question 4

How do animals change from reproductive to vegetative stage and back again? (3 types)

Answer 4

1. Incorporation - reproductive habits incorporated into vegetative lifestyle phase (e.g. shoals of fish, parasitic males & self fertilising bisexuals)
2. Separation - complete separation of vegetative and reproductive lifestyle phases (bees & salmon)
3. Alteration - switches between vegetative and reproductive lifestyle phases (most animals and mostly seasonally, frog vs sheep & courtship behaviours/ brood care behaviours)

Question 5

What are the 3 methods of gamete transfer?

Answer 5

1. Spermatophore - males produce packaged sperm to be used by the females when required (e.g. stick insects)
2. Quasi copulation - no female penetration but attempt at close deposition of gametes (e.g. frogs)
3. True copulation - deposition of sperm into female tract (e.g. Llamas)

Question 6

How does duration, timing and frequency of copulation change between species?

Answer 6

1. Duration - usually short particularly in prey animals
   (rabbits - seconds, bulls - seconds, boars - minutes, dogs - minutes)
2. Frequency - depends on the species, individual, health& stamina and availability of females
3. Timing - usually coincidenet with ovulation
   except bats for sperm storage and humans for pleasure

Question 7

How does the reproductive strategy change between species (e.g. number of mates)?

Answer 7

1. Monogamy - paired stable mating (geese)
2. Promiscuity - indiscriminate mating within a group (chimpanzees)
3. Polygamy - individual has more than one mate
   a. ) Polyandry - female has many males (bees)
   b. ) Polygyny - male has many females (deer)