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- https://bio.libretexts.org/Courses/Gettysburg_College/01%3A_Ecology_for_All/08%3A_Life_Histories/8.02%3A_Semelparity_versus_IteroparityOne class of models that tries to explain the differential evolution of semelparity and iteroparity examines the shape of the trade-off between offspring produced and offspring forgone (offspring that...One class of models that tries to explain the differential evolution of semelparity and iteroparity examines the shape of the trade-off between offspring produced and offspring forgone (offspring that will not be produced). In the first graph, the marginal cost of offspring produced is decreasing (each additional offspring is less "expensive" than the average of all previous offspring) and the marginal cost of offspring forgone is increasing.
- https://bio.libretexts.org/Workbench/General_Ecology_Ecology/Chapter_8%3A_Life_Histories/4%3A_Semelparity_versus_IteroparityIn this situation, the organism only devotes a portion of its resources to reproduction, and uses the rest of its resources on growth and survivorship so that it can reproduce again in the future [6] ...In this situation, the organism only devotes a portion of its resources to reproduction, and uses the rest of its resources on growth and survivorship so that it can reproduce again in the future [6] . However, it is also possible (second graph) for the marginal cost of offspring produced to increase, and for the marginal cost of offspring forgone to decrease.
- https://bio.libretexts.org/Courses/Gettysburg_College/01%3A_Ecology_for_All/08%3A_Life_Histories/8.01%3A_What_is_life_historyOptimality is important for the study of life history theory because it serves as the basis for many of the models used, which work from the assumption that natural selection, as it works on a life hi...Optimality is important for the study of life history theory because it serves as the basis for many of the models used, which work from the assumption that natural selection, as it works on a life history traits, is moving towards the most optimal group of traits and use of energy (Stearns, 1976).
- https://bio.libretexts.org/Courses/Gettysburg_College/01%3A_Ecology_for_All/10%3A_Population_modeling/10.07%3A_Life_TablesLife tables are a classic technique used to understand how populations change. By determining the life span of individuals in a population and how many offspring they produce human demographers and e...Life tables are a classic technique used to understand how populations change. By determining the life span of individuals in a population and how many offspring they produce human demographers and ecologists can summarize key aspects of a population, such as average life span, generation time, and growth rate. This allows comparisons between different populations and species.
- https://bio.libretexts.org/Courses/Citrus_College/Citrus_College_General_Biology_Textbook/15%3A_Population_and_Community_Ecology/15.02%3A_Population_Demographics_and_DynamicsPopulations are individuals of a species that live in a particular habitat. Ecologists measure characteristics of populations: size, density, and distribution pattern. Life tables are useful to calcul...Populations are individuals of a species that live in a particular habitat. Ecologists measure characteristics of populations: size, density, and distribution pattern. Life tables are useful to calculate life expectancies of individual population members. Survivorship curves show the number of individuals surviving at each age interval plotted versus time.
- https://bio.libretexts.org/Workbench/General_Ecology_Ecology/Chapter_8%3A_Life_Histories/1%3A_What_is_life_historyFor example, "optimal investment in offspring is where the decrease in total number of offspring is equaled by the increase of the number who survive". [7] Optimality is important for the study of lif...For example, "optimal investment in offspring is where the decrease in total number of offspring is equaled by the increase of the number who survive". [7] Optimality is important for the study of life history theory because it serves as the basis for many of the models used, which work from the assumption that natural selection, as it works on a life history traits, is moving towards the most optimal group of traits and use of energy.
- https://bio.libretexts.org/Workbench/General_Ecology_Ecology/Chapter_10%3A_Population_modeling/10.5%3A_Life_TablesLife tables are a classic technique used to understand how populations change. By determining the life span of individuals in a population and how many offspring they produce human demographers and e...Life tables are a classic technique used to understand how populations change. By determining the life span of individuals in a population and how many offspring they produce human demographers and ecologists can summarize key aspects of a population, such as average life span, generation time, and growth rate. This allows comparisons between different populations and species.
