![Page 1: Unit 3 Human Population and Carrying Capacity](https://reader036.vdocuments.us/reader036/viewer/2022081511/56816692550346895dda709d/html5/thumbnails/1.jpg)
Unit 3 Human Population and Carrying Capacity
![Page 2: Unit 3 Human Population and Carrying Capacity](https://reader036.vdocuments.us/reader036/viewer/2022081511/56816692550346895dda709d/html5/thumbnails/2.jpg)
Population Dynamicsis the study of how populations change in size, density and age distribution.
Size- total number of individualsDensity- number of individuals in a certain space( spatial distribution)Age distribution- the proportion of individuals of each age in a population
![Page 3: Unit 3 Human Population and Carrying Capacity](https://reader036.vdocuments.us/reader036/viewer/2022081511/56816692550346895dda709d/html5/thumbnails/3.jpg)
Four Factors affecting Population size?
How do populations increase or decrease?
![Page 4: Unit 3 Human Population and Carrying Capacity](https://reader036.vdocuments.us/reader036/viewer/2022081511/56816692550346895dda709d/html5/thumbnails/4.jpg)
Immigration: movement of individuals of a species into a country or an area
Emigration: movement of individuals of a species out of a country or area
![Page 5: Unit 3 Human Population and Carrying Capacity](https://reader036.vdocuments.us/reader036/viewer/2022081511/56816692550346895dda709d/html5/thumbnails/5.jpg)
Natality – birthrate
Mortality- deathrate
![Page 6: Unit 3 Human Population and Carrying Capacity](https://reader036.vdocuments.us/reader036/viewer/2022081511/56816692550346895dda709d/html5/thumbnails/6.jpg)
Population Change=(Natality+Immigration)-(Mortality+Emigration
![Page 7: Unit 3 Human Population and Carrying Capacity](https://reader036.vdocuments.us/reader036/viewer/2022081511/56816692550346895dda709d/html5/thumbnails/7.jpg)
Exponential GrowthA population with few or no resource limitations grows exponentially.Rate 1% - 2%Examine the data: starts slowly and gradually increases Invasive speciesWhooping crane p.169
![Page 8: Unit 3 Human Population and Carrying Capacity](https://reader036.vdocuments.us/reader036/viewer/2022081511/56816692550346895dda709d/html5/thumbnails/8.jpg)
However, this is not true for most populations.
Together biotic potential (essentially how fast they can reproduce without the environment having an impact) and environmental resistance (environmental limits that affect population growth) determine a carrying capacity for a population.
Carrying capacity (K) - the maximum population of a particular species that a given habitat can support.
![Page 9: Unit 3 Human Population and Carrying Capacity](https://reader036.vdocuments.us/reader036/viewer/2022081511/56816692550346895dda709d/html5/thumbnails/9.jpg)
Fig. 9-4
![Page 10: Unit 3 Human Population and Carrying Capacity](https://reader036.vdocuments.us/reader036/viewer/2022081511/56816692550346895dda709d/html5/thumbnails/10.jpg)
Logistic Growthinvolves rapid exponential growth followed by a steady decline in population growth until the population size levels off.This occurs because the population encounters environmental resistance and its rate of growth decreases as it approaches the carrying capacity.After leveling off, the population fluctuates slightly above and below the carrying capacity.
![Page 11: Unit 3 Human Population and Carrying Capacity](https://reader036.vdocuments.us/reader036/viewer/2022081511/56816692550346895dda709d/html5/thumbnails/11.jpg)
Fig. 9-5
Overshoot- when organisms use up their resources and temporarily exceed their carrying capacity
This happens because of a reproductive time lag: the period needed for the birthrate to drop and the deathrate to rise as a result of resource overconsumption.
![Page 12: Unit 3 Human Population and Carrying Capacity](https://reader036.vdocuments.us/reader036/viewer/2022081511/56816692550346895dda709d/html5/thumbnails/12.jpg)
Fig. 9-6
A dieback or crash occurs unless a switch to an alternate resources or leaves the area.Reindeer introduced on an island in Alaska had no alternate resource and the death of the herd.
![Page 13: Unit 3 Human Population and Carrying Capacity](https://reader036.vdocuments.us/reader036/viewer/2022081511/56816692550346895dda709d/html5/thumbnails/13.jpg)
Limiting Factor -when a particular condition or factor can be identified as a key component that limits the size of a population.
Air, water, nutrients, food, shelter, etc.
There are four categories of limiting factors:
What limits population growth?
![Page 14: Unit 3 Human Population and Carrying Capacity](https://reader036.vdocuments.us/reader036/viewer/2022081511/56816692550346895dda709d/html5/thumbnails/14.jpg)
1. Availability of Raw Materials
Plants need nitrogen and magnesium from the soil as raw materials to manufacture chlorophyll.
Adding fertilizer to the soil is a way of preventing nitrogen from being a limiting factor.
![Page 15: Unit 3 Human Population and Carrying Capacity](https://reader036.vdocuments.us/reader036/viewer/2022081511/56816692550346895dda709d/html5/thumbnails/15.jpg)
2. Availability of Energy
Plants require energy from sunlight.Animals require food energy.
Food webs can be changed.
![Page 16: Unit 3 Human Population and Carrying Capacity](https://reader036.vdocuments.us/reader036/viewer/2022081511/56816692550346895dda709d/html5/thumbnails/16.jpg)
3. Accumulation of Waste Products
commonly a limiting factor for bacteria and organisms that live in small ecosystems such as puddles, pools and petri dishes.not a limiting factor for most organisms
![Page 17: Unit 3 Human Population and Carrying Capacity](https://reader036.vdocuments.us/reader036/viewer/2022081511/56816692550346895dda709d/html5/thumbnails/17.jpg)
4. Interactions among Organisms
Since cottontail rabbits and white tailed deer eat the twigs of many species of small trees, they have a limiting effect on the size of some tree populations.
Parasites and predators cause the premature death of individuals thus limiting the size of the populations.
![Page 18: Unit 3 Human Population and Carrying Capacity](https://reader036.vdocuments.us/reader036/viewer/2022081511/56816692550346895dda709d/html5/thumbnails/18.jpg)
Factors Affecting Population Size
Fig. 9-3
![Page 19: Unit 3 Human Population and Carrying Capacity](https://reader036.vdocuments.us/reader036/viewer/2022081511/56816692550346895dda709d/html5/thumbnails/19.jpg)
Types of Population Change curves
stable- fluctuates above and below the carrying capacity
irruptive- a stable population which on occasion will explode or irrupt
cyclic- cyclical fluctuations over a defined period of time
irregular- no order the fluctuations- chaos
![Page 20: Unit 3 Human Population and Carrying Capacity](https://reader036.vdocuments.us/reader036/viewer/2022081511/56816692550346895dda709d/html5/thumbnails/20.jpg)
Natural Population Curves
Fig. 9-7
![Page 21: Unit 3 Human Population and Carrying Capacity](https://reader036.vdocuments.us/reader036/viewer/2022081511/56816692550346895dda709d/html5/thumbnails/21.jpg)
Where Might the human population be on this growth curve?
![Page 22: Unit 3 Human Population and Carrying Capacity](https://reader036.vdocuments.us/reader036/viewer/2022081511/56816692550346895dda709d/html5/thumbnails/22.jpg)
![Page 23: Unit 3 Human Population and Carrying Capacity](https://reader036.vdocuments.us/reader036/viewer/2022081511/56816692550346895dda709d/html5/thumbnails/23.jpg)
Human population
Video clip : http://www.youtube.com/watch?v=4BbkQiQyaYc
![Page 24: Unit 3 Human Population and Carrying Capacity](https://reader036.vdocuments.us/reader036/viewer/2022081511/56816692550346895dda709d/html5/thumbnails/24.jpg)
See worksheet: Applying Human Populations