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The storage effect is not a model for population growth (such as the Lotka–Volterra equation) itself, but is an effect that appears in non-additive models of population growth. [5] Thus, the equations shown below will work for any arbitrary model of population growth, but will only be as accurate as the original model.
When a cell population reaches a certain density, the amount of required growth factors and nutrients available to each cell becomes insufficient to allow continued cell growth. [citation needed] This is also true for other organisms because an increased density means an increase in intraspecific competition. Greater competition means an ...
Gravitational biology is the study of the effects gravity has on living organisms. Throughout the history of the Earth life has evolved to survive changing conditions, such as changes in the climate and habitat. However, one constant factor in evolution since life first began on Earth is the force of gravity.
A plant only reacts to gravity if the gravistimulation is maintained for longer than a critical amount of time, called the minimal presentation time (MPT). For many plant organs the MPT lies somewhere between 10 and 200 seconds, and therefore a clinostat should rotate on a comparable timescale in order to avoid a gravitropic response.
Disks Flown on STS-40 STS-40 Cargo Bay configuration. G-616, formally known as GAS canister #G-616: The Effect of Cosmic Radiation on Static Computer Media & Plant Seeds Exposure to Microgravity was an experiment flown on the Space Shuttle as a self-contained experiment, as part of STS-40.
Consider a population at harvested at a constant harvest level . If the population falls (due to a bad winter or illegal harvest) this will ease density-dependent population regulation and increase yield, moving the population back to , a stable equilibrium. In this case, a negative feedback loop creates stability.
The falling population growth rate as population increases can be modelled effectively with the logistic growth model. [3] The rate of change of population density eventually falls to zero, the point ecologists have termed the carrying capacity (K). However, a population can only grow to a very limited number within an environment. [3]
The weak Allee effect is a demographic Allee effect without a critical population size or density. The distinction between the two terms is based on whether or not the population in question exhibits a critical population size or density. A population exhibiting a weak Allee effect will possess a reduced per capita growth rate (directly related ...