Lecture 7: age pop. Flashcards
(22 cards)
What is age structure?
A: The number of individuals in each age class of a population.
What is a cohort?
A: A group of individuals born during the same time period (age class).
Why do life tables focus on females?
A: Because birth rate depends on the number of females, and it’s hard to determine male contribution
What are the three types of survivorship curves?
Type I (low mortality when young), Type Il (equal survival at all ages), Type III (high mortality when young).
What is a life table?
describes the mortality and survival patterns of a population
Q: What are the two types of life tables?
A: Cohort (dynamic) and static (time-specific).
Q: What is Ix?
A: The proportion of the original cohort surviving to age x
What is dx?.
A: The proportion of the cohort dying between age x and x
Q: What is qx?
A: The age-specific mortality rate
What is bx?.
A: The average number of offspring per surviving individual in an age class
What is Ro (net reproductive rate)?
A: The sum of Ix x bx across all age classes. Ro > 1 = growing population,
Ro < 1 = declining.
What is genetic structure?
The distribution of genetic variation within and among populations.
What is gene flow?
: The exchange of genetic material between populations.
How do you quantify genetic variation?
By the proportion of heterozygotes in a population.
What reduces genetic variation in small populations?
Genetic drift and inbreeding.
What is genetic drift?
Random changes in allele frequencies, more impactful in small populations.
What is inbreeding?
Mating between relatives, increases homozygosity and risks harmful traits
What is inbreeding depression?
Reduced fitness and survival due to expression of harmful recessive alleles.
What is effective population size?
The number of individuals who actually reproduce and pass genes on.
What is minimum viable population (MVP)?
The smallest population size needed to ensure long-term survival.
Q: What is a Population Viability Analysis (PVA)?
A tool to estimate the likelihood that a species will persist for a set time (e.g., 95% chance over 500 years).
age class
group of individuals that are the same age in a population.
