32 Questions
What is the term for over one act of reproduction during a lifetime?
Iteroparity
Which species are known to exhibit semelparity?
Antechinus, Phascogale, and Dasykaluta
What is the term for the physiological mechanism leading to death in the northern quoll?
Different than in other four genera
What happens to the reproductive output of females as they age?
It declines
What was observed in the long-term study on Isle of Rhum on red deer?
A correlation between population density and fecundity
What happens to the mortality rates of milk hinds?
They increase with age
What is the term for the strategy of investing everything in one last attempt at reproduction?
Terminal investment strategy
Which group of females suckle their young more than prime age females?
Old lactating females
What is the primary goal of natural selection regarding the costs and benefits of a behaviour?
To minimize costs and maximize benefits
What is the term for the highest milk fat content of any known mammal?
Grey seal trait
What is the primary advantage of giving birth to precocial young, as seen in cavies?
Improved pup survival rate
What is the energy cost of lactation in terms of basal metabolic rate (BMR)?
2.5-5.0 times BMR
What is the term for a single act of reproduction during a lifetime?
Semelparity
What is the primary disadvantage of altricial young, as seen in house mice?
Increased vulnerability to predators
What is the energy cost of gestation in terms of basal metabolic rate (BMR)?
1.2-1.5 times BMR
What is the primary trade-off in reproductive investment strategies?
Number of breeding attempts versus longevity
What is the primary definition of benefits in the context of behaviour?
How a behaviour increases inclusive fitness
What is the primary reason for selection to maximize benefits while minimizing costs?
To optimize an individual's reproductive success
What is the primary characteristic of reproductive strategies?
They are any adaptation associated with the production of an individual's own offspring or the young of another individual
What is the primary reason why grey seal pups have a high milk fat content?
To allow the pup to quickly gain fat in a short period of time
What is the primary difference between cavies and house mice in terms of their young?
Cavies give birth to precocial young, while house mice give birth to altricial young
What is the primary consequence of breeding on an individual's longevity?
It decreases an individual's longevity
What is the primary trade-off associated with reproductive investment strategies?
How many breeding attempts to make versus how much energy to invest in each attempt
What is the primary consequence of reproduction on an individual's energy reserves?
It decreases an individual's energy reserves, requiring the individual to increase energy intake or utilize fat reserves
What is the key difference between iteroparity and semelparity?
Iteroparity is a strategy of investing in future reproduction, whereas semelparity is a strategy of investing in current reproduction.
What is the phenomenon where reproductive output declines with age?
Reproductive senescence
Why do milk hinds have lower fecundity in the following year?
Because they fail to accumulate fat reserves
What is the term for the strategy of investing everything in one last attempt at reproduction, typically at the end of an individual's expected natural lifespan?
Terminal investment strategy
What is the relationship between population density and fecundity in red deer?
Fecundity decreases with population density
Why do very old females suckle their young more than prime age females?
Because they are more likely to die soon and invest in current reproduction
What is the primary difference between the two facultatively semelparous species mentioned in the text?
One species has a different physiological mechanism leading to death
What is the primary finding of the long-term study on Isle of Rhum on red deer females?
Red deer females that raise a calf successfully have a higher mortality rate
Study Notes
Costs and Benefits of Behaviour
- Every behaviour has associated costs and benefits, where benefits increase inclusive fitness and costs reduce it.
- Selection acts to maximize benefits while minimizing costs, leading to optimal behaviours that give the greatest reward relative to cost.
Reproductive Investment Strategies
- Reproductive strategies refer to morphological, physiological, or behavioural adaptations associated with producing offspring or caring for another's young.
- Examples include genitalia morphology, mating behaviour, gestation period, litter size and sex ratio, lactation period, milk composition, and offspring care.
Reproductive Strategies in Different Species
- Grey seal:
- Gives birth on land, vulnerable to predators
- High milk fat content to fatten pup quickly
- One pup per litter, once a year
- Cavy/guinea pig:
- Gives birth to precocial young
- Female mass: 700g, litter size: 1-6, pup mass: 70g
- Pregnancy lasts 65 days, total litter mass equivalent to 40% of female mass
- House mouse:
- Gives birth to altricial young
- Female mass: 25g, litter size: 4-15, pup mass: 1.5g
- Pregnancy lasts 19 days, total litter mass equivalent to 60% of female mass
Reproductive Trade-Offs
- Basic trade-off: how many breeding attempts in a lifetime?
- Reproduction is energetically expensive: gestation (1.2-1.5 times BMR), lactation (2.5-5.0 times BMR)
- Females must increase energy intake or utilize fat reserves
- Breeding lowers longevity
Semelparity and Iteroparity
- Semelparity: single act of reproduction in a lifetime (e.g., Antechinus, Phascogale, Dasykaluta species)
- Iteroparity: multiple acts of reproduction in a lifetime
- Facultative semelparity: occurs in some populations of two other genera, and the northern quoll (different physiological mechanism leading to death)
Case Study: Red Deer
- Long-term study on Isle of Rhum illustrates costs and trade-offs associated with reproduction
- Females categorized by reproductive experience and costs
- Fecundity, fat reserves, mortality rates, and age-dependent fecundity rates are affected by reproductive costs
- Population density and age interact to affect reproductive outcomes
- Terminal investment strategy: old females invest everything in one last breeding attempt
Costs and Benefits of Behaviour
- Every behaviour has associated costs and benefits, where benefits increase inclusive fitness and costs reduce it.
- Selection acts to maximize benefits while minimizing costs, leading to optimal behaviours that give the greatest reward relative to cost.
Reproductive Investment Strategies
- Reproductive strategies refer to morphological, physiological, or behavioural adaptations associated with producing offspring or caring for another's young.
- Examples include genitalia morphology, mating behaviour, gestation period, litter size and sex ratio, lactation period, milk composition, and offspring care.
Reproductive Strategies in Different Species
- Grey seal:
- Gives birth on land, vulnerable to predators
- High milk fat content to fatten pup quickly
- One pup per litter, once a year
- Cavy/guinea pig:
- Gives birth to precocial young
- Female mass: 700g, litter size: 1-6, pup mass: 70g
- Pregnancy lasts 65 days, total litter mass equivalent to 40% of female mass
- House mouse:
- Gives birth to altricial young
- Female mass: 25g, litter size: 4-15, pup mass: 1.5g
- Pregnancy lasts 19 days, total litter mass equivalent to 60% of female mass
Reproductive Trade-Offs
- Basic trade-off: how many breeding attempts in a lifetime?
- Reproduction is energetically expensive: gestation (1.2-1.5 times BMR), lactation (2.5-5.0 times BMR)
- Females must increase energy intake or utilize fat reserves
- Breeding lowers longevity
Semelparity and Iteroparity
- Semelparity: single act of reproduction in a lifetime (e.g., Antechinus, Phascogale, Dasykaluta species)
- Iteroparity: multiple acts of reproduction in a lifetime
- Facultative semelparity: occurs in some populations of two other genera, and the northern quoll (different physiological mechanism leading to death)
Case Study: Red Deer
- Long-term study on Isle of Rhum illustrates costs and trade-offs associated with reproduction
- Females categorized by reproductive experience and costs
- Fecundity, fat reserves, mortality rates, and age-dependent fecundity rates are affected by reproductive costs
- Population density and age interact to affect reproductive outcomes
- Terminal investment strategy: old females invest everything in one last breeding attempt
Understand the principles of behaviour in the context of evolution, including the costs and benefits of behaviour and reproductive investment strategies.
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