Within the camera trap grid, Meredith has simulated “lion” activity by conducting playbacks of lion roars at a subset of camera sites. Short-term behavioral changes are rarely investigated, and little information is available on the factors that select for short- over long-term avoidance nor the time-scale (i.e., hours, days, weeks) of these responses. Prey could obtain additional foraging opportunities by utilizing more of the landscape, while suffering compensatory costs from devoting additional time and energy to predator detection and defense. Prey may compensate for these inabilities - or supplement their broad-scale responses - by instead avoiding areas that predators have frequented within the previous few hours or days. Landscape-level antipredator behaviors may not manifest if prey cannot predict predator activity patterns or are unable to pay the fitness costs of avoiding predators long-term. Itasca Biological Station and Laboratories.Biochemistry, Molecular Biology and Biophysics.Population Unit Organizer.doc Population Dynamics.ppt Population Dynamics (1). How are the patterns of lynx and hare populations linked?īelow you will find the links to the Population Dynamics Unit Organizer and the slide presentation What is a logistic graph and how does one find the carrying capacity on it?ħ. What is an exponential growth curve and what does it represent?Ħ. What is the difference between density dependent and density independent limiting factors?ĥ. What are the four variables that control population size?Ģ. You are not expected to do the mathematical calculations but you should be familiar with the graphs and what they portray.ġ. More specifically this shows the impact of the plague on the human population in the middle ages and the follow on recovery and growth.ħ. This video of populations from Bozeman Science does an excellent job of explaining the material related to population dynamics. The following graph shows the impact of disease on population size. Play the predator - prey game by clicking on the image below:Ħ. Here is an interesting video that showcases both animals in their native habitat. Carrying capacity here is a range based on predator and prey sinusoidal population curves.ĥ. The lynx and hare predator prey population case study is widely taught. Without enough food, the predator population also declines. As the predator population increases, the prey population decreases. As the population of prey increases, predators have more food, are healthier and can give birth to and sustain more offspring. Population curves for predator prey are often sinusoidal. The predator prey relationship is an example of a density dependent factor. These factors include earthquakes, fires, floods and seasonal changes that trigger migrations to and from an ecosystem.ĭensity dependent factors are factors that are a function of population size such as disease, food availability, mate availability, etc.Ĥ. Limiting factors fall into one of two categories: density independent factors and density dependent factors.ĭensity independent factors are factors that impact a population's size regardless of the size of the population. Ecologists determine the carrying capacity of an ecosystem by identifying the limiting factors that impact population size. the number of individual organisms of a species that the ecosystem can support.ģ. The steady state size of the population defines the ecosystem's carrying capacity for that species, i.e. As the population approaches its steady state, the growth rate slows. This is the period of fastest growth rate. After ten to eleven generations the growth rate accelerates, becoming exponential. which in turn reflects the limitations imposed on the population by factors within the ecosystem. The graph below shows population growth as it reaches steady state. Within an ecosystem, growth does not continue unchecked. The graph below illustrates this exponential growth.Ģ. In a twenty four hour period (72 reproductive events), one bacteria gives rise to 4,722,366,482,869,645,213,696 individuals. For example, fast growing bacteria divide every 20 min. Assuming organisms reproduce at a fixed rate, population size doubles at each reproductive event. Unconstrained population growth is exponential (see graph below). When the rates of increase and decrease are equal, the population size is constant and we say the population is in a steady state. The rates of birth and immigration increase the population size while the rates of death and emigration decrease the population size. Their size is controlled by four (4) parameters. Species populations in an ecosystem are dynamic. ( back to Honors Biology Table of Contents 2020-21)ġ.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |