Breeding Biology I Flashcards
Life History
Life History
Changes in physiological traits and behaviors throughout the course of a lifetime
What is life history in an evolutionary context?
How do individuals maximize the number of genes contributed to future generations?
What does life history research focus on?
Processes that affect the schedule of survival and reproduction
What are life history traits?
- Adaptive evolutionary responses
- Determine potential limits to variation in traits (ex: all petrels are constrained to lay one egg despite environmental conditions)
What life history traits are specific to seabirds?
- Few offspring / small clutch size
- Large adult size
- Late age maturity
- Long-lived
- High parental care
What are life-table traits?
- Indicative of an individual’s performance
- Consequences of how life history traits interact with the environment (ex: some species the number of eggs laid varies between individuals each year)
What are some challenges with studying life history in seabirds?
- Requires long periods of time
- Expensive
- Important parts of the population are not accessible to study (ex: young birds remain at sea until they first breed)
- Human life spans are not much longer in comparison
Do juveniles spend more energy on growth or reproduction?
Growth
Do adults spend more energy on growth or reproduction?
Reproduction
(This is the energy that is left over after energy spent in order to maintain a healthy body condition)
What is a life-history strategy (goal) and what are some examples?
Combination of traits utilized to maximize lifetime reproductive success ex:
1. Fitness strategies
2. Survivorship strategies
Fitness
The ability of an individual to survive, reproduce and propagate genes
Fecundity
The number of offspring produced by an individual
Reproductive value
The expected reproduction of an individual from their current age onward given that they have survived to that current age (ex: reproductive vale = higher in young adults)
What are strategies utilized to maximize fitness?
- Resource allocation to:
1. Self
2. Offspring
3. Gender (male vs. female) - Reproductive vs. self-maintenance
- Produce few offspring of high fitness
- Produce many offspring of low fitness
What are the three types of survivorship strategies?
- Type I: Die old (survivorship = high)
- Type II: Death rate = constant across age (survivorship = low but not specific to reproductive stage)
- Type III: Die early in life (survivorship = low)
What is R selection?
- Type III
- Short life span
- Grow fast
- Mature fast
- High fecundity
- No parental care
What is K selection?
- Type I
- Long life span
- Mature late
- Low fecundity
- High parental care
Are R and K appropriate for categorizing ALL survivorship strategies?
- No
- Convenient, but inadequate
- There is a wide variety of traits (some species may overlap between strategies)
What are the two ends of the reproductive frequency spectrum?
- Semelparous: One and done (ex: salmon)
- Iteroparous: Repeat performers (ex: albatrosses)
What are the two ends of the reproductive spectrum in regards to the number and size of offspring?
- Many small offspring (ex: salmon = thousands of small eggs)
- Few large offspring (ex: albatrosses = 1 big egg)
What are some life-history trade-offs (constraints)?
- Energetic
- Physiological
- Functional
- Environmental
How does the environmental stability affect r-selected species?
- Environment is unstable
- Opportunist strategy
How does the environmental stability affect k-selected species?
- Environment is stable
- “Good competitor” strategy
- Reproductive risk = spread across multiple efforts (both parents look after the young)
How does parental care affect mating systems?
- Biparental care: Monogamy = favored
- Precocial / receive strong maternal care: Polygamy = favored
- Male investment is unnecessary: Polygynous harems = favored
