Lecture 2 (1b) - Alternative Parental Strategies

Question 1

Alternative parental strategies

Answer 1

• r- and K- selected modes of reproduction
• the maternal burden of embryonic and neonatal nutrition
• parental priorities
• shared care: increasing the parental contribution of males

Question 2

Modes of reproduction

Species can be:

Answer 2

• r-selected
• K-selected

Question 3

r-selected species

Answer 3

• reproduce and develop rapidly
• highly prolific
  
  • eg polytocus
• **little/no parental ** investment
  
  • eg most insects

Question 4

K-selected species

Answer 4

• reproduce and develop slowly
• few offspring
  
  • eg monotocus
• **high **level of parental investment
  
  • eg humans

Question 5

Balancing investment

Answer 5

Question 6

What’s the biological basis of the inverse correlation between the number of offspring and the level of parental investment?

Answer 6

• environment at “carrying capacity” so can only accommodate limited number of offspring - sufficient resources in parent to invest in increased care for young
• need to ensure limited number of offspring survive
• resource demands of increased parental care limit the number of offspring that can be produced

Question 7

Burdens that fall to the mother

Answer 7

• embryo nutrition
• neonatal nutrition
• post-weaning nutrition

Question 8

Embryo nutrition

burden falls to mother

Answer 8

• oviparous / ovovivoparous
  
  • oviparous - animals that give birth to embryos inside eggs
  • ovoviviparous - conceive an egg but retain the egg inside (monotremes)
  • oviparous - animals that lay eggs, with little or no other embryonic development within the mother
  • ovoviviparous - embryos develop inside eggs that are retained within the mother’s body until they are ready to hatch
  • the embryo is nourished by the egg yolk - the mother’s energy goes to producing rich egg yolk that’s rich in proteins and lipids
• viviparous - give birth to live young that develop inside the body of the parent
  
  • mother has to nourish the baby with maternal proteins, carbs, lipids, all secreted from the reproductive tract (uterus in humans)

Question 9

Neonatal nutrition (born)

burden falls to mother

Answer 9

mammals

• mother must forage to produce sufficient food for her to make milk, which is more food that she would take just to survive
• lactogenesis = synthesis of milk proteins
• lactation = release of this

non-mammals

• don’t have to produce milk but must forage for 2, bring back whatever it is that the baby requires

Question 10

Post-weaning nutrition

(mammals only)

Answer 10

• usually mother that secures first “solids” for infants post-weaning