Lecture fourteen Flashcards
Age Class
Group of individuals born at roughly the same time
Age Structure
Number of different age classes and number of individuals in each age class
Cohort
Individuals that make up an age class
Birth Rate
Number of female offspring produced per female in a particular age class
Why is birth rate concerned primarily with females?
It is limited by the number of females, difficult to quantify the contribution of each male
Death Rate
Number of females that die per age class in the population
Survivorship Curve
Number of individuals alive vs. age
Type I Curve
Low mortality when young, humans
Type II Curve
Equal survival through life, birds
Type III Curve
High mortality when young, fish
Age Pyramid
Snapshot of an population age structure at some point in time
Life Table
Tabulation of birth and death of each age class in a population
Cohort Life Table
Dynamic, follows one cohort from birth to death
Static Life Table
Time specific, snapshot of the population at one point in time
What do life tables allow us to quantify?
Whether the size of a population is increasing, stable, or decreasing
What is x?
Age class
What is nx?
Total number of individuals at each age x
What is Fx?
Total number of offspring produced at each age class
What is lx?
Proportion of the original cohort surviving from birth to age x
What is dx?
Proportion of the original cohort dying during each age class
Can dx be summed?
Yes
What is qx?
Age specific mortality rate. Indicates intensity of mortality at a certain age
Can qx be summed?
No
What is bx?
Age specific birth rate
