Population Cycles
Population Cycles - Related Videos
09:32
Cell Cycle Analysis
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2023
Cell cycle refers to the set of events through which a cell grows, replicates its genome, and ultimately divides into two daughter cells through the process of mitosis. Because the amount of DNA in a cell shows characteristic changes throughout the cycle, techniques known as cell cycle analysis can be used to separate a population of cells according to the different phases of cell cycle they are in, based on their varying DNA content.This video will cover the principles behind cell cycle...
14:47
Population Growth - Student Protocol
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2019
Exponential Population Growth Model ExpandNOTE: In these experiments you will use computer software to simulate different types of growth models. HYPOTHESES: The experimental hypothesis might be that if we increase either R, the reproductive rate or the initial population size, NT, that this will increase the population size after 10 generations in an exponential growth model compared to unmanipulated control populations. The null hypothesis may be that populations of different R and initial...
04:45
Population Growth - Concepts
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2019
Population Models An ecological population is a group of individuals of a single species living in an area at the same time. To persist, a population must either grow or maintain its size. Population ecology is the study of how population size and age distribution change over time through interactions with other species and the environment as well as with individuals of their own species. A particularly important feature that is studied by ecologists is the rate at which a population grows or...
00:54
What are Biogeochemical Cycles?
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2019
The most common elements in organic molecules, carbon, hydrogen, oxygen, nitrogen, sulfur, and phosphorus, are only available in the ecosystem in limited amounts. Therefore, these nutrients must be recycled through both biotic and abiotic components of the ecosystem, in processes generally called biogeochemical cycles. Biogeochemical Cycles and Decomposition The matter that makes up living organisms, like water, carbon, nitrogen, sulfur and phosphorous, exist in limited quantities within the...
01:00
The Water Cycle
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2019
The Earth’s hydrosphere includes all of the areas where the storage and movement of water occurs. Since water is the basis of all living processes, the cycling of water is extremely important to ecosystem dynamics. The water cycle begins as the sun warms surface water on the land and in oceans, causing it to evaporate and enter the atmosphere as vapor. The water vapor condenses into clouds and eventually falls as precipitation in the form of rain, snow or hail. After falling back to the...
FAQs
Delayed effects of reproduction can turn population growth into a repeating pattern. When reproduction increases population size, the resulting demand for resources or exposure to predators, competitors, or disease may affect the population later rather than immediately. That lag can allow numbers to continue rising before limiting pressures dominate, producing alternating growth and decline instead of a steady approach to a fixed level.
Resource limitation, competition, predation, and disease can each strengthen or weaken population feedback. Their relative influence affects how rapidly a population increases, when decline begins, and how large the change becomes. Environmental conditions can modify these pressures as well, so the timing and amplitude of cycles may vary across populations or change as climate and other conditions shift.
Predator–prey relationships provide a biological feedback through which changes in one population can influence another. Predation can contribute to rises and falls in population size, making these interactions central to interpreting fluctuations within biological communities. Examining such dynamics helps biologists connect changes observed in wildlife populations with broader questions about regulation, community change, and ecosystem stability.
Biologists examine wildlife survey data collected across time to identify recurring changes in population size or density. They can compare when increases and declines occur, estimate the timing and amplitude of fluctuations, and evaluate whether patterns are seasonal or multi-year. Relating these observations to environmental change helps reveal how conditions influence population regulation.
Comparing cycle timing and amplitude across species shows whether populations respond similarly or differently to environmental conditions. These comparisons can reveal changes in population regulation associated with climate or other environmental shifts. They also help place individual population trends in a broader biological context, supporting interpretation of community change rather than treating each fluctuation as an isolated event.
Population-cycle studies help conservationists distinguish recurring fluctuations from broader changes that may require attention. The same information can support pest-management decisions by clarifying when populations tend to increase or decline. Because cycles also inform understanding of ecosystem stability and predator–prey dynamics, they connect monitoring results with practical strategies for managing biological communities.