Unit 3 Lecture 16 Flashcards
What does life history mean?
Patter of investment into Growth, maintenance, and reproduction
- history of events during a life that are related to births and deaths
Energy captured could be converted into 3 different things:
- Growth
- Maintenance
- Reproduction
What is life history trait?
The events themselves or the rates that quantify the transition
- Specific ways organisms manage growth, maintenance, and reproduction to maximize lifetime reproductive success (fitness)
What are the two steps of survival?
- Survival to first breeding
- Chance of dying (survival)
What are the 2 steps of Growth?
- Size at first breeding
- Adult size
What are the 6 steps of reproduction?
- Juvenile
- Age at first breeding (α)
- Adult
- Reproduction (fecundity)
- Reproductive interval
- Lifespan
Give an example of life history
- offspring number and size
- growth rate
- size at maturity
- age at maturity
- offspring size and number
- parental care
- Number of breeding attempts
- Life span (dead)
Name some reasons why life history traits are important and interesting
- Vary a lot among organisms
- Targets of strong selection (can evolve rapidly i.e. heritable variation)
- Directly affect population growth/dynamics
- Trade-offs
What is the purpose of a trade-off
Making a decision that is going to maximize your fitness
- does NOT tell you which is the best decision
What is quality v. quantity tradeoff?
Has to do with offspring size/quality and number of offspring you produce
- number of seeds produced per plant and the average seed mass (negative relationship)
- trade off on whether you choose to have very small seeds and overwhelming the environment with your seeds, to put more out there than your predators could eat ORRRR having just a few seeds making them really well provisioned (plant version of parental care)
Explain the trade-off in lizards?
- Variation in number of eggs per nest in lizards
- Depending on where the lizard is located, that will impact the number of eggs and the mean egg size
What does life history strategy mean?
How you allocate energy
Explain the quality-quantity trade-off in human hunter-gatherers
Higher fertility –> lower offspring size at age 5; Lower fertility –> higher offspring size at age 5
Explain the experiment on the Lesser Black-backed Gull
- Ruedi Nager removed each egg from the nest of this gull
- When he did this, he can get females to lay more eggs than she normally would (if you took an egg away from her)
- He could make different females lay normal number or increase number of eggs
- Then he had a different female foster the clutch of eggs that were laid
- Observed probability that chicks from those eggs survived to independence
He did this experiment with multiple different females to get a range of different clutch sizes and had them mothered by different mothers
Explain the experimental evidence from the Black-backed gull
When you had fewer eggs laid, fewer offspring died
- isn’t due to the mom NOT actually taking care of the eggs properly
- seems to be a trade off that the more eggs the bird was forced to lay, the lower quality the eggs were i.e. lower survival