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Understand population dynamics through exponential and logistic growth models, carrying capacity, quadrat sampling, mark and recapture method, mutualism, biomes, keystone species, and ecological succession in this informative quiz review.
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EXPONENTIALGROWTH • BIRTH RATE >DEATH RATE • POPULATION STARTS OUT SLOWLY THEN INCREASES RAPIDLY • J-SHAPED CURVE • CANNOT KEEP GROWING LIKE THIS DUE TO LACK OF RESOURCES
LOGISTIC GROWTH • POPULATION GROWTH BEGINS FAST BUT LEVELS OFF WHEN RESOURCES (food, space, air, etc.) ARE USED UP & CARRYINGCAPACITY IS REACHED • CARRYING CAPACITY = # OF ORGANISMS ECOSYSTEM CAN SUPPORT • S-SHAPED CURVE
At what level do the deer reach the CARRYING CAPACITY of this island? Carrying capacity is around 80 deer – the number at which it levels out.
Quadrat Sampling • Scientists use a quadrat (a set measuring area) to sample organisms in a large area. • This method is best used for organisms that experience little to no movement.
Suppose the following field is divided into 10 cm x 10 cm quadrats. 1) What would be the DENSITY of Buttercups in quadrat B? 2) What would be the DENSITY of Dandelions using ALL selected quadrats (A-E)? 3) Using this DENSITY, how many Dandelions would you predict are in the whole field?
Suppose the following field is divided into 10 cm x 10 cm quadrats. 1) What would be the DENSITY of Buttercups in quadrat B? • Density = # organisms/Area • # buttercups in quadrat B = 2 • Area of quadrat B = 10cmX10cm = 100cm2 • Density = 2/100 cm2 or reduced to 1/50 cm2
Suppose the following field is divided into 10 cm x 10 cm quadrats. 2) What would be the DENSITY of Dandelions using ALL selected quadrats (A-E)? • Density = # organisms/Area • # dandelions = 8 • Area of quadrat A-E = 100cm2 x 5 = 500 cm2 • Density = 8/500 cm2 or reduced to 2/125 cm2
3. Using this density, how many dandelions are in the entire field? • You must first determine the area of all quadrats • = 100 cm2 X 25 quadrats = 2500cm 2 • Then create a proportion with the density you determined from the previous question. • 2 x __________ = ___________ • 125cm2 2500cm 2 • X= 40
Mark and Recapture Scientists capture, mark, and release a certain number of individuals in a species. Some time later, they recapture organisms of the same species. Using a formula that compares the number of recaptured animals that were marked to those that are not provides an estimate of the population size. This method is best used when sampling animals that move, are relatively easy to capture, don’t molt or shed frequently, and don’t experience excessive immigration or emigration.
Commensalism (+/0)One organism benefits while the other is unaffected
BIOMES - Major ecosystems that occur over large areas of Earth with similar biotic and abiotic factors and:
TAIGA– Northern coniferous (Boreal) forest – (think Christmas trees)
KEYSTONE SPECIES • A species vital to the success of the ecosystem
SUCCESSION • Change in an ecosystem over time
Climax Community • A mature, stable ecosystem that will change very little • Lots of biodiversity (different species of organisms)