https://www.khanacademy.org/science/ap-biology/ecology-ap/energy-flow-through-ecosystems/v/organism-life-history-and-fecundity 2023-06-22T09:47:49.118446933Z Life history strategies and fecundity Species exhibit diverse life histories, lifespans, and reproduction rates, as seen in elephants, rabbits, and salmon. Fecundity measures reproduction rate, while semelparity and iteroparity describe single or multiple reproductive events. Natural selection influences these traits based on factors like energy availability, predation, and disease, leading species to make trade-offs between growth, reproduction, and survival. video https://cdn.kastatic.org/googleusercontent/JDiuemvnwTbYw_p4pibZqdwvKLuYD2VBHIx0j291i5Z7Z3fhmKKnnQzMwNOj9PZAUUikuQ-JmfJYuTSxftY1i7d1 Life history strategies and fecundity Species exhibit diverse life histories, lifespans, and reproduction rates, as seen in elephants, rabbits, and salmon. Fecundity measures reproduction rate, while semelparity and iteroparity describe single or multiple reproductive events. Natural selection influences these traits based on factors like energy availability, predation, and disease, leading species to make trade-offs between growth, reproduction, and survival. https://cdn.kastatic.org/ka-youtube-converted/mAdUjImDx58.mp4/mAdUjImDx58.mp4 707 Population growth and human impact on ecosystems https://www.khanacademy.org/science/ap-biology/ecology-ap/population-ecology-ap/a/hs-population-ecology-review 2025-03-13T12:19:34.272335663Z Population ecology review article https://www.khanacademy.org/science/ap-biology/ecology-ap/population-ecology-ap/v/density-dependent-and-density-independent-population-regulation 2024-05-06T19:22:43.24334365Z Population regulation There are two types of population regulation: density-dependent and density-independent. Density-dependent factors, like competition for resources, predation, disease, and waste accumulation, limit population growth based on population density. Density-independent factors, such as natural disasters, affect populations regardless of density. Understanding these factors helps us consider human population growth and potential carrying capacity. Sal Khan video https://cdn.kastatic.org/googleusercontent/aowVW739U5AOhvKG8kQdvlwy8fNmRKnQqcx1yn1OXju_YjMV2JFSLAKXaL840jkOZMn8_rg_1RC7BYhwvGCJQyiY Population regulation There are two types of population regulation: density-dependent and density-independent. Density-dependent factors, like competition for resources, predation, disease, and waste accumulation, limit population growth based on population density. Density-independent factors, such as natural disasters, affect populations regardless of density. Understanding these factors helps us consider human population growth and potential carrying capacity. https://cdn.kastatic.org/ka-youtube-converted/6IS_M6CX7FE.mp4/6IS_M6CX7FE.mp4 633 Population growth and human impact on ecosystems https://www.khanacademy.org/science/biology/ecology/population-ecology/a/population-size-density-and-dispersal 2024-05-06T19:22:43.24334365Z Population size, density, & dispersal What an ecological population is. How scientists define and measure population size, density, and distribution in space. article https://www.khanacademy.org/science/ap-biology/ecology-ap/population-ecology-ap/v/population-growth-rate-based-on-birth-and-death-rates 2023-06-22T09:47:49.118446933Z Population growth rate based on birth and death rates Calculating population growth rate is simpler than it seems. By comparing birth and death rates, we can intuitively find the growth rate. Here, we show the formula to calculate population growth rate, using calculus notation. Although this formula may look intimidating, it represents a straightforward concept, making it easy to grasp and apply in biology. video https://cdn.kastatic.org/googleusercontent/0xXeNPbJyaMTIuCZD2GzsRUI-qCoZ9FZReuvuMlccLkSpvceCF99cSKenjero96QjZIR2QxyuAYcQiNHJnaldEf6MA Population growth rate based on birth and death rates Calculating population growth rate is simpler than it seems. By comparing birth and death rates, we can intuitively find the growth rate. Here, we show the formula to calculate population growth rate, using calculus notation. Although this formula may look intimidating, it represents a straightforward concept, making it easy to grasp and apply in biology. https://cdn.kastatic.org/ka-youtube-converted/R2yPeLJsPOo.mp4/R2yPeLJsPOo.mp4 194 Population growth and human impact on ecosystems https://www.khanacademy.org/science/ap-biology/ecology-ap/disruptions-to-ecosystems/a/hs-human-impact-on-ecosystems-review 2021-04-29T08:01:14Z Human impact on ecosystems review article