Diversity of
reproductive
strategies
, Diversity of reproductive strategies
Reproductive strategies in animals
Ensure continued existence of species, successful reproduction is essential. Animals use
rvarious reproductive strategies to increase reproductive success in different environments.
Reproductive strategy: way species budgets energy expenditure to produce viable offspring.
Two main types of reproductive strategies:
r-strategy (concave curve)
K-strategy (convex curve)
r-strategy
Animals expend more energy in producing many offspring, but little in
parental care.
Many offspring die before adulthood, enough survive to continue species.
(Eg. leatherback turtles)
K-strategy
Animals produce fewer offspring, expend much energy for parental care.
Offspring have better chance of surviving to adulthood.
(Eg. elephants, lions).
Survivorship curves illustrate number of organisms survive at different stages of life span.
K- and r-strategy animals show distinctly different survivorship curves.
Reproductive strategies are discussed:
- Courtship - Ovipary, Ovovivipary & Vivipary - Amniotic egg
- External & Internal fertilisation - Precocial & Altricial development - Parental care
Courtship
Behavioural patterns of male & female animals, leading to mating & ultimately reproduction.
Ensures both sexes ready for mating.
Identify mating partners of same species, prevent unsuccessful mating with different species,
waste of energy. (Male use energy for courtship, female save for laying eggs)
Choose suitable mating partner. Females choose bigger, stronger, attractive physical features,
result in more & healthier offspring.
reproductive
strategies
, Diversity of reproductive strategies
Reproductive strategies in animals
Ensure continued existence of species, successful reproduction is essential. Animals use
rvarious reproductive strategies to increase reproductive success in different environments.
Reproductive strategy: way species budgets energy expenditure to produce viable offspring.
Two main types of reproductive strategies:
r-strategy (concave curve)
K-strategy (convex curve)
r-strategy
Animals expend more energy in producing many offspring, but little in
parental care.
Many offspring die before adulthood, enough survive to continue species.
(Eg. leatherback turtles)
K-strategy
Animals produce fewer offspring, expend much energy for parental care.
Offspring have better chance of surviving to adulthood.
(Eg. elephants, lions).
Survivorship curves illustrate number of organisms survive at different stages of life span.
K- and r-strategy animals show distinctly different survivorship curves.
Reproductive strategies are discussed:
- Courtship - Ovipary, Ovovivipary & Vivipary - Amniotic egg
- External & Internal fertilisation - Precocial & Altricial development - Parental care
Courtship
Behavioural patterns of male & female animals, leading to mating & ultimately reproduction.
Ensures both sexes ready for mating.
Identify mating partners of same species, prevent unsuccessful mating with different species,
waste of energy. (Male use energy for courtship, female save for laying eggs)
Choose suitable mating partner. Females choose bigger, stronger, attractive physical features,
result in more & healthier offspring.
