Life History Flashcards
What is the definition of life history?
The lifetime pattern of growth, development and reproduction of an organism
Life history characteristics are traits that affect and are reflected in the life table of an organism.
What are some key life history characteristics?
- When to mature/reproduce
- What kind of mating strategy
- Lifespan
These characteristics influence the survival and reproductive success of organisms.
What is the maximum length of male and female pilot whales?
- Males: up to 7m
- Females: up to 5.5m
This demonstrates sexual dimorphism in pilot whales.
What is the weight range for male and female pilot whales?
- Males: up to 2,300kg
- Females: up to 1,300kg
Weight differences are significant between sexes.
What is the lifespan of male and female pilot whales?
- Males: ~40 years
- Females: ~60 years
Lifespan varies significantly by sex in this species.
At what age do male and female pilot whales mature sexually?
- Males: around 8 years
- Females: around 13 years
Maturity age impacts reproductive strategies.
What is fitness in the context of life history?
The genetic contribution by an individual’s descendants to future generations
Fitness is a critical measure of evolutionary success.
What does reproductive effort involve?
Tradeoffs
Organisms must balance efforts in reproduction and survival.
What is a negative correlation in life history traits?
An inverse relationship among various traits
Improving one trait may negatively impact another.
What are the characteristics of slow life history?
- Low adult mortality
- Slower development
- Late maturity
- Lower fecundity
These traits are often seen in long-lived species.
What are the characteristics of fast life history?
- High adult mortality
- Faster development
- Early maturity
- Higher fecundity
Fast life history traits often favor rapid reproduction.
What do r-selected species typically exhibit?
- Short-lived
- High fecundity
- Rapid development
- Small body size
- Low offspring survival
- Minimal parental care
- Not resource-limited
- Good colonizers
Examples include weeds and insects.
What do K-selected species typically exhibit?
- Long-lived
- Slow growth
- Competitive
- Delayed and repeated reproduction
- Larger body size
- Parental care
- Resource-limited
- Poor colonizers
Examples include whales and humans.
What is the r-K selection theory?
Life history characteristics reflect adaptations to variable and stable conditions
Although it has been replaced by the life-history paradigm, many themes remain relevant.
What is the significance of genetic differences in r-K dichotomy?
Genetic differences via natural selection contribute to the r-K dichotomy
This highlights the evolutionary pressures shaping life history traits.
What are hermaphrodites?
Organisms that possess both male and female organs
Examples include certain plants and earthworms.
What is monogamy?
A lasting bond between one male and one female
It is most prevalent among birds and rare among mammals.
What is polygyny?
An individual male controls or gains access to multiple females
This strategy can enhance reproductive success for males.
What is polyandry?
Females call the shots in mating arrangements
This is less common but can lead to unique social structures.
What is sexual selection?
The process where certain traits increase an individual’s chances of mating
Traits may be costly, such as size in male killer whales impacting hunting efficiency.
