Cohort survival and net reproduction
A cohort life table follows individuals born together.
Key knowledge
A cohort life table follows individuals born together. Its survival fraction l_x is the fraction reaching age x; conditional interval survival is p_x=l_{x+1}/l_x where l_x>0. With daughters per surviving female m_x at specified birth-pulse ages, R₀=Σ_{x≥1}l_xm_x is expected lifetime daughters per newborn female. A cross-sectional age count is not automatically a cohort survival curve.
Values and equations
p_x=l_{x+1}/l_x; R₀=Σ_{x≥1}l_xm_x
- x
- discrete age in the stated census interval age interval
- l_x,p_x
- survival from birth and conditional next-interval survival 1
- m_x
- daughters at the age-x birth pulse per surviving female 1
- R₀
- expected lifetime daughters per newborn female 1
Conditions and scope
- Specify observation, sex and reproductive timing conventions; complete survival tracking or an appropriate censoring model is needed.
- The demographic reference model ignores density dependence, migration and mate limitation. R₀ is reproduction over a lifetime, rather than a per-time growth rate or the number of grandchildren.
Sources · 2
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
- Lectures on Theoretical Ecology, §§5.1 and6.1: census conventions, survival and Euler–LotkaStephen P. Ellner — Cornell University (2009)Reference guide · PDF
- The evolution of life histories in spatially heterogeneous environments, equation1 and its homogeneous-environment limitsTadeusz J. Kawecki and Stephen C. Stearns (1993)Reference guide · PDF
Evidence and review
Read Ellner§5.1 life-table definitions and warning about pre-/post-breeding census mixtures, and§6.1 survival/reproduction interpretation; original Kawecki–Stearns equation1 conditions constrain homogeneous age-based inference. No empirical cohort data are fabricated.
2026-10-10 · Independent AI editorial review: All six exact compact records, equations/variables/conditions and eighteen origin edges, plus actual bounded primary sections/abstracts listed below. This is independent AI editorial review, not laboratory validation or whole-Biology revalidation. Receipt: biology-quantitative-independent-review.1.
Entry details
Permanent link to this entry ↗- Record identity
- uni-bio-cohort-life-table
- Revision
- core.1
- Structured reference record
- University core expansion