Population dynamics
 Populations of organisms experience
exponential growth
 As the population gets larger, it grows
fas...
Carrying Capacity
 Limiting factors cause populations to
stop increasing
 When a population has stabilized, it has
reach...
NumberofYeastCells
Time (hours)
Carrying capacity
 If population falls below carrying
capacity, the population will increase.
 If population is above carrying
capacity, i...
Ranges of population
growth patterns
Reproduce very quickly over short
period of time
 Enables organisms to survive in
ch...
Slow reproduction, producing a few
young
 Organisms live in balanced, stable
environment
 Organism usually is long-lived...
Limits to Population
Growth
Density-dependent factors
 Increasing effect as population
increases
 Disease, parasites, fo...
Density-independent factors
 Not influenced by population size
 Affect all populations
 Usually abiotic factors
 Tempe...
Characteristics of Population Growth
0
Exponential
growth
J curve S curve
Population
Time
DISEASE
SPACE
PREDATORS
FOOD
Car...
Which interval in the diagram below
represents the population reaching
equilibrium near carrying capacity?
Factors that help maintain
balance in ecosystem
Competition
 Organisms strive for (want or need)
same thing (share niche)...
Predation
 One organism kills and eats another
 Removes less-fit members from
population
 Prevents overpopulation
 Pre...
http://www.bbc.co.uk/schools/gcsebit
esize/science/ocr_gateway_pre_2011/
environment/2_compete_or_die2.sht
ml
Predator-prey relationship
 Predation affects population size
 Populations of predators and prey
fluctuate (change) toge...
 Both predator and prey experience
changes in numbers.
 1.       predators ↑, prey ↓
 2.       prey ↓, predators ↓
 3....
Effects of crowding and
stress
Crowding usually causes stress in
organisms
 Aggression
 Decrease in parental care
 Decr...
Human population growth 
DemographyDemography
 Study of human population growthStudy of human population growth
 Worldwi...
 Humans able to reduceHumans able to reduce
environmental effects and controlenvironmental effects and control
limiting f...
•Increase food production
•Control disease organisms
Growth rate
 Difference between birth rate and deathDifference between birth rate and death
raterate
 If births increase...
 What would happen to the population size ifWhat would happen to the population size if
the birth rate was greater than t...
Life expectancyLife expectancy
 Live longer with better nutritionLive longer with better nutrition
and health care (lower...
Fertility rateFertility rate
 Number of offspring produced byNumber of offspring produced by
femalefemale
McCaughey Septuplets
Octomom
Age and population growth
Age structureAge structure
 Number of people at different age levelsNumber of people at differe...
Age Distribution
U.S. Population Rwandan Population
Males MalesFemales Females
Age Distribution
Stable – about
same amount in
each group
Gr...
Increasing, decreasing or stable
population?
Increasing population – wide base
Increasing, decreasing or stable
population?
Stable – about same in age groups
Could decrease slightly because
there are f...
Impact of Human Population IncreaseImpact of Human Population Increase
 More resources are consumed (used)More resources ...
Impact of Human Population IncreaseImpact of Human Population Increase
 Fewer resources for future generationsFewer resou...
Impact of Human Population IncreaseImpact of Human Population Increase
 Urban development (building) leads toUrban develo...
Impact of Human Population IncreaseImpact of Human Population Increase
 Increased fertilizer and pesticide use toIncrease...
Biodiversity
 Number of different species that live inNumber of different species that live in
an areaan area
 Richest e...
How much biodiversity?
Very little – only two species
None – only one species
Lots of biodiversity –
many different specie...
 Larger islands have more biodiversityLarger islands have more biodiversity
than smaller islands, or isolated areas.than ...
 Affects predator-prey relationshipsAffects predator-prey relationships
 Brings stability to ecosystemBrings stability t...
Threats to Biodiversity
1.1. Habitat lossHabitat loss
 Habitat is gone, no longer availableHabitat is gone, no longer ava...
2. Habitat fragmentation2. Habitat fragmentation
 Habitat divided into smaller partsHabitat divided into smaller parts
3. Habitat degradation3. Habitat degradation
 Quality of habitat is lessenedQuality of habitat is lessened
 Water, land ...
4.4. Introduction of exotics (non-nativeIntroduction of exotics (non-native
species or invasive species)species or invasiv...
Kudzu
Melaleuca Trees from Australia
living in Florida Everglades
The Everglades are not supposed
to be a forest!!
Zebra
M...
Gypsy Moth
Conservation Biology
Protects biodiversity by preserving speciesProtects biodiversity by preserving species
 Habitat pres...
Human Activities
Threatening Environment
Rainforest burning and destructionRainforest burning and destruction
 increases ...
Pesticide usePesticide use
PestsPests
developdevelop
resistance toresistance to
pesticidepesticide
Pesticide killsPestic...
 Can be harmful to other organismsCan be harmful to other organisms
 Rachel Carson – increased publicRachel Carson – inc...
Bioaccumulation/Biomagnification
 Pesticides accumulate in higherPesticides accumulate in higher
quantities farther up fo...
Also called
biomagnification
or
bioaccumulation
Biocontrol
 Alternative to pesticidesAlternative to pesticides
 Biological (live) organisms control pestsBiological (liv...
 The first biocontrol insects against melaleuca inThe first biocontrol insects against melaleuca in
Florida were put to w...
Introduction of Bull frogs in the Arizona Desert
Effect of introducing bull frogs to the Arizona desert ecosystem
Saving the native Arizona Leopard Frog
Cycles in nature
 Abiotic (nonliving) substances moveAbiotic (nonliving) substances move
through biotic (living) and abio...
Chemical Cycles
Water cycle
CondensationCondensation
 Water vaporWater vapor →→ liquid waterliquid water
EvaporationEvaporation
 Liquid ...
Bellringer
Draw a plant (autotroph) on a sheet ofDraw a plant (autotroph) on a sheet of
paper.paper.
Be sure your drawing ...
Stomata are found on plant leaves.
Draw some on your picture.
Plant leaf viewed under microscope
Now trace the
path of wat...
 Transpiration (involves livingTranspiration (involves living
plants)plants)
Loss of water through plantLoss of water th...
 Destruction of rainforest affectsDestruction of rainforest affects
water cyclewater cycle
 Cutting trees prevents trans...
The Water Cycle
Acid Rain
 Nitrous oxides (NONitrous oxides (NOxx) and sulfur) and sulfur
oxides (SOoxides (SO22))
 Released by burning ...
Acid Rain
Carbon cycle
 requires bacteria to cycle nutrients (sorequires bacteria to cycle nutrients (so
does the nitrogen cycle)do...
ADDSADDS
ADDS
REMOVESADDS
ADDS
CO
2
 PlantsPlants removeremove COCO22 from atmospherefrom atmosphere
by photosynthesisby photosynthesis
 Water + carbon diox...
 Fewer plants to remove COFewer plants to remove CO22 fromfrom
atmosphereatmosphere
 Levels of COLevels of CO22 will be ...
Natural Sources of CO2
 VolcanoesVolcanoes
 OceansOceans
 Cellular respirationCellular respiration
 Oxygen + glucose +...
1. Now, what about carbon dioxide and
oxygen?
2. Draw arrows and label the gas that plants
take in through their stomata.
...
Chemical Cycles
Nitrogen cycle
 Atmosphere is greatest source (78%) ofAtmosphere is greatest source (78%) of
nitrogen gas (Nnitrogen gas ...
N2
N2
N2
N2
N2
N2
N2
N2
N2
 AirAir →→ nitrogen fixing bacterianitrogen fixing bacteria →→ plantplant
→→ animalanimal
 Nitrogen fixing bacteria are ...
Human Impact on Environment
 Human population growingHuman population growing
exponentially due to advances inexponential...
Tracking Human Impact
1. Global warming
 COCO22 increase in atmosphereincrease in atmosphere
traps heat from suntraps heat from sun
 COCO22 re...
Global Warming and Ocean Pollution
2. Use of Pesticides
 Can harm unintended organismsCan harm unintended organisms
 Bioaccumulation/BiomagnificationBioacc...
3. Humans affect Biodiversity
 Habitat loss (gone)Habitat loss (gone)
 Habitat fragmentation (smallerHabitat fragmentati...
Population Sampling
 Uses a small part of a larger populationUses a small part of a larger population
to estimate the siz...
How to do a Random Sample
 Divide larger area into equally sizedDivide larger area into equally sized
smaller areas.small...
 Average the number of organisms byAverage the number of organisms by
dividing the total organisms counted individing the...
Populations to cycles 2015
Populations to cycles 2015
Populations to cycles 2015
Populations to cycles 2015
Populations to cycles 2015
Populations to cycles 2015
Populations to cycles 2015
Populations to cycles 2015
Populations to cycles 2015
Populations to cycles 2015
Populations to cycles 2015
Populations to cycles 2015
Populations to cycles 2015
Populations to cycles 2015
Populations to cycles 2015
Populations to cycles 2015
Populations to cycles 2015
Populations to cycles 2015
of 103

Populations to cycles 2015

pops
Published on: Mar 4, 2016
Published in: Education      
Source: www.slideshare.net


Transcripts - Populations to cycles 2015

  • 1. Population dynamics  Populations of organisms experience exponential growth  As the population gets larger, it grows faster.  Leads to population “explosions”  Results in J-shaped curve
  • 2. Carrying Capacity  Limiting factors cause populations to stop increasing  When a population has stabilized, it has reached carrying capacity  Carrying capacity is the number of organisms of one species an environment can support indefinitely
  • 3. NumberofYeastCells Time (hours) Carrying capacity
  • 4.  If population falls below carrying capacity, the population will increase.  If population is above carrying capacity, it will decrease.
  • 5. Ranges of population growth patterns Reproduce very quickly over short period of time  Enables organisms to survive in changing, unstable habitat  Organism usually short-lived  Mosquitoes, flies, bacteria
  • 6. Slow reproduction, producing a few young  Organisms live in balanced, stable environment  Organism usually is long-lived  Elephant, human
  • 7. Limits to Population Growth Density-dependent factors  Increasing effect as population increases  Disease, parasites, food, space, competition
  • 8. Density-independent factors  Not influenced by population size  Affect all populations  Usually abiotic factors  Temperature, storms, floods, drought, habitat disruption (usually from humans building)
  • 9. Characteristics of Population Growth 0 Exponential growth J curve S curve Population Time DISEASE SPACE PREDATORS FOOD Carrying capacity
  • 10. Which interval in the diagram below represents the population reaching equilibrium near carrying capacity?
  • 11. Factors that help maintain balance in ecosystem Competition  Organisms strive for (want or need) same thing (share niche)  Resources (food, water, territory) are limited  Plants and animals must “compete” for resources.  Density-dependent
  • 12. Predation  One organism kills and eats another  Removes less-fit members from population  Prevents overpopulation  Predator-prey relationship
  • 13. http://www.bbc.co.uk/schools/gcsebit esize/science/ocr_gateway_pre_2011/ environment/2_compete_or_die2.sht ml
  • 14. Predator-prey relationship  Predation affects population size  Populations of predators and prey fluctuate (change) together
  • 15.  Both predator and prey experience changes in numbers.  1.       predators ↑, prey ↓  2.       prey ↓, predators ↓  3.       predators ↓, prey ↑  4. prey ↑, predators ↑  Important for health of natural population
  • 16. Effects of crowding and stress Crowding usually causes stress in organisms  Aggression  Decrease in parental care  Decrease in fertility  Decreased resistance to disease  Occurs over carrying capacity
  • 17. Human population growth  DemographyDemography  Study of human population growthStudy of human population growth  Worldwide human population hasWorldwide human population has increased exponentiallyincreased exponentially   Very Dense Population!
  • 18.  Humans able to reduceHumans able to reduce environmental effects and controlenvironmental effects and control limiting factorslimiting factors Eliminate competing organismsEliminate competing organisms
  • 19. •Increase food production
  • 20. •Control disease organisms
  • 21. Growth rate  Difference between birth rate and deathDifference between birth rate and death raterate  If births increase and deaths decreaseIf births increase and deaths decrease then population growsthen population grows
  • 22.  What would happen to the population size ifWhat would happen to the population size if the birth rate was greater than the deaththe birth rate was greater than the death rate?rate?  What would happen to the population size ifWhat would happen to the population size if the birth rate was lower than the death rate?the birth rate was lower than the death rate?  What would happen to the population size ifWhat would happen to the population size if the birth rate was equal to the death rate?the birth rate was equal to the death rate?
  • 23. Life expectancyLife expectancy  Live longer with better nutritionLive longer with better nutrition and health care (lowers deathand health care (lowers death rate)rate)  Health and size of humans hasHealth and size of humans has increased over time due toincreased over time due to improved nutritionimproved nutrition
  • 24. Fertility rateFertility rate  Number of offspring produced byNumber of offspring produced by femalefemale
  • 25. McCaughey Septuplets
  • 26. Octomom
  • 27. Age and population growth Age structureAge structure  Number of people at different age levelsNumber of people at different age levels  Rapid growth countries have ageRapid growth countries have age structure with wide basestructure with wide base  Stable populations have equal amountsStable populations have equal amounts in each age groupin each age group
  • 28. Age Distribution
  • 29. U.S. Population Rwandan Population Males MalesFemales Females Age Distribution Stable – about same amount in each group Growing – wide at base Most of population is young and will enter reproductive age Number of those giving birth will increase over time
  • 30. Increasing, decreasing or stable population? Increasing population – wide base
  • 31. Increasing, decreasing or stable population? Stable – about same in age groups Could decrease slightly because there are fewer young children who will eventually reproduce
  • 32. Impact of Human Population IncreaseImpact of Human Population Increase  More resources are consumed (used)More resources are consumed (used)  More fossil fuels are burned whichMore fossil fuels are burned which causes increased COcauses increased CO22 levels and acidlevels and acid rainrain
  • 33. Impact of Human Population IncreaseImpact of Human Population Increase  Fewer resources for future generationsFewer resources for future generations  Deforestation –trees are cut down andDeforestation –trees are cut down and land clearedland cleared
  • 34. Impact of Human Population IncreaseImpact of Human Population Increase  Urban development (building) leads toUrban development (building) leads to habitat destruction, water runoff, and soilhabitat destruction, water runoff, and soil erosion.erosion.
  • 35. Impact of Human Population IncreaseImpact of Human Population Increase  Increased fertilizer and pesticide use toIncreased fertilizer and pesticide use to meet need for more foodmeet need for more food
  • 36. Biodiversity  Number of different species that live inNumber of different species that live in an areaan area  Richest environments are in warmRichest environments are in warm areasareas
  • 37. How much biodiversity? Very little – only two species None – only one species Lots of biodiversity – many different species Lots of biodiversity – many different species
  • 38.  Larger islands have more biodiversityLarger islands have more biodiversity than smaller islands, or isolated areas.than smaller islands, or isolated areas. Most biodiversity in largest area Least biodiversity in smallest area One large area will have more biodiversity than many isolated, small areas
  • 39.  Affects predator-prey relationshipsAffects predator-prey relationships  Brings stability to ecosystemBrings stability to ecosystem Biodiversity
  • 40. Threats to Biodiversity 1.1. Habitat lossHabitat loss  Habitat is gone, no longer availableHabitat is gone, no longer available
  • 41. 2. Habitat fragmentation2. Habitat fragmentation  Habitat divided into smaller partsHabitat divided into smaller parts
  • 42. 3. Habitat degradation3. Habitat degradation  Quality of habitat is lessenedQuality of habitat is lessened  Water, land and air pollutionWater, land and air pollution
  • 43. 4.4. Introduction of exotics (non-nativeIntroduction of exotics (non-native species or invasive species)species or invasive species)  species not usually found in thespecies not usually found in the areaarea  populations of exotics “explode”populations of exotics “explode”  few competitors and predatorsfew competitors and predators in new habitatin new habitat  may take over niche andmay take over niche and replace native speciesreplace native species Fearsome Frogs Intro
  • 44. Kudzu Melaleuca Trees from Australia living in Florida Everglades The Everglades are not supposed to be a forest!! Zebra Mussels
  • 45. Gypsy Moth
  • 46. Conservation Biology Protects biodiversity by preserving speciesProtects biodiversity by preserving species  Habitat preservationHabitat preservation  CaptivityCaptivity  Reintroduction programsReintroduction programs Endangered Extinct Siberian Tiger Endangered
  • 47. Human Activities Threatening Environment Rainforest burning and destructionRainforest burning and destruction  increases COincreases CO22 in atmospherein atmosphere  COCO22 causes global warmingcauses global warming  Prevents transpirationPrevents transpiration  Water vapor entering atmosphereWater vapor entering atmosphere through plant leavesthrough plant leaves
  • 48. Pesticide usePesticide use PestsPests developdevelop resistance toresistance to pesticidepesticide Pesticide killsPesticide kills fewerfewer organismsorganisms over timeover time
  • 49.  Can be harmful to other organismsCan be harmful to other organisms  Rachel Carson – increased publicRachel Carson – increased public awareness about DDTawareness about DDT  DDT weakened bird egg shellsDDT weakened bird egg shells  Reduced number of American BaldReduced number of American Bald EaglesEagles
  • 50. Bioaccumulation/Biomagnification  Pesticides accumulate in higherPesticides accumulate in higher quantities farther up food chainquantities farther up food chain (mercury and lead)(mercury and lead)  Small amount of pesticide in CSmall amount of pesticide in C11, more in, more in CC22, even more in C, even more in C33..  Can be deadly for organisms higher upCan be deadly for organisms higher up in food chainin food chain
  • 51. Also called biomagnification or bioaccumulation
  • 52. Biocontrol  Alternative to pesticidesAlternative to pesticides  Biological (live) organisms control pestsBiological (live) organisms control pests  does not use harmful chemicalsdoes not use harmful chemicals  Ex. ladybugs control aphids; frogsEx. ladybugs control aphids; frogs control insectscontrol insects
  • 53.  The first biocontrol insects against melaleuca inThe first biocontrol insects against melaleuca in Florida were put to work in 1997, whenFlorida were put to work in 1997, when melaleuca snout beetles,melaleuca snout beetles, Oxyops vitiosa,Oxyops vitiosa, werewere released into the Everglades. In 2002, it wasreleased into the Everglades. In 2002, it was believed that the bugs, were making headway.believed that the bugs, were making headway.
  • 54. Introduction of Bull frogs in the Arizona Desert
  • 55. Effect of introducing bull frogs to the Arizona desert ecosystem
  • 56. Saving the native Arizona Leopard Frog
  • 57. Cycles in nature  Abiotic (nonliving) substances moveAbiotic (nonliving) substances move through biotic (living) and abioticthrough biotic (living) and abiotic (nonliving) parts of the environment(nonliving) parts of the environment  Water, carbon and nitrogen are in fixedWater, carbon and nitrogen are in fixed amounts on Earthamounts on Earth  They can’t be made so they must beThey can’t be made so they must be cycled (used over and over)cycled (used over and over)
  • 58. Chemical Cycles
  • 59. Water cycle CondensationCondensation  Water vaporWater vapor →→ liquid waterliquid water EvaporationEvaporation  Liquid waterLiquid water →→ water vaporwater vapor PrecipitationPrecipitation  Water returns to Earth as rain, snow,Water returns to Earth as rain, snow, sleet, hailsleet, hail
  • 60. Bellringer Draw a plant (autotroph) on a sheet ofDraw a plant (autotroph) on a sheet of paper.paper. Be sure your drawing includes theBe sure your drawing includes the following and that the parts are labeled:following and that the parts are labeled: RootsRoots StemStem LeavesLeaves Now draw a consumer somewhere onNow draw a consumer somewhere on your paper.your paper.
  • 61. Stomata are found on plant leaves. Draw some on your picture. Plant leaf viewed under microscope Now trace the path of water through the plant - transpiration
  • 62.  Transpiration (involves livingTranspiration (involves living plants)plants) Loss of water through plantLoss of water through plant leavesleaves Plants can affect water cycle;Plants can affect water cycle; water cycle can affect plantswater cycle can affect plants
  • 63.  Destruction of rainforest affectsDestruction of rainforest affects water cyclewater cycle  Cutting trees prevents transpirationCutting trees prevents transpiration  Less water into atmosphereLess water into atmosphere
  • 64. The Water Cycle
  • 65. Acid Rain  Nitrous oxides (NONitrous oxides (NOxx) and sulfur) and sulfur oxides (SOoxides (SO22))  Released by burning fossil fuelsReleased by burning fossil fuels (coal)(coal)  React with moisture in air toReact with moisture in air to become nitric and sulfuric acidbecome nitric and sulfuric acid  Acid precipitation kills plants andAcid precipitation kills plants and affects water quality because itaffects water quality because it lowers pHlowers pH
  • 66. Acid Rain
  • 67. Carbon cycle  requires bacteria to cycle nutrients (sorequires bacteria to cycle nutrients (so does the nitrogen cycle)does the nitrogen cycle)  Affected by destruction of rainforest andAffected by destruction of rainforest and burning fossil fuels (industry and cars)burning fossil fuels (industry and cars)  Burning fossil fuels and cellularBurning fossil fuels and cellular respirationrespiration ADDSADDS COCO22 to theto the atmosphereatmosphere
  • 68. ADDSADDS ADDS REMOVESADDS ADDS CO 2
  • 69.  PlantsPlants removeremove COCO22 from atmospherefrom atmosphere by photosynthesisby photosynthesis  Water + carbon dioxide + sunlight →Water + carbon dioxide + sunlight → glucose + oxygenglucose + oxygen  HH22O + COO + CO22 + sunlight → C+ sunlight → C66HH1212OO66 + O+ O22  Destruction of rainforestDestruction of rainforest  removes trees from surface ofremoves trees from surface of EarthEarth
  • 70.  Fewer plants to remove COFewer plants to remove CO22 fromfrom atmosphereatmosphere  Levels of COLevels of CO22 will be higherwill be higher  COCO22 in atmosphere causes globalin atmosphere causes global warmingwarming CO2 (greenhouse gases)
  • 71. Natural Sources of CO2  VolcanoesVolcanoes  OceansOceans  Cellular respirationCellular respiration  Oxygen + glucose + waterOxygen + glucose + water → ATP +→ ATP + carbon dioxide + watercarbon dioxide + water  OO22 + C+ C66HH1212OO66 + H+ H22O → ATP + COO → ATP + CO22 + H+ H22OO  Decomposition by bacteria and fungiDecomposition by bacteria and fungi
  • 72. 1. Now, what about carbon dioxide and oxygen? 2. Draw arrows and label the gas that plants take in through their stomata. 3. Draw arrows out of the stomata and label the gas that is produced by the plant. 4. What happened to the carbon that went in? 5. What uses the gas that is released by the plant? 6. Draw arrows out of the consumer and label the gas that is produced by the consumer. 7. What gas is produced by the consumer? 8. Where does it go?
  • 73. Chemical Cycles
  • 74. Nitrogen cycle  Atmosphere is greatest source (78%) ofAtmosphere is greatest source (78%) of nitrogen gas (Nnitrogen gas (N22))  Plants and animalsPlants and animals cannotcannot use theuse the form of nitrogen found in the airform of nitrogen found in the air  Nitrogen fixing bacteria convert nitrogenNitrogen fixing bacteria convert nitrogen compounds Ncompounds N22(in air) and ammonia into(in air) and ammonia into a form plants can use (nitrate or NOa form plants can use (nitrate or NO33)) http://www.classzone.com/books/ml_science_share/vis_ sim/em05_pg20_nitrogen/em05_pg20_nitrogen.html
  • 75. N2 N2 N2 N2 N2 N2 N2 N2 N2
  • 76.  AirAir →→ nitrogen fixing bacterianitrogen fixing bacteria →→ plantplant →→ animalanimal  Nitrogen fixing bacteria are found onNitrogen fixing bacteria are found on legumes (bean plants)legumes (bean plants)  Can be affected by fertilizer whichCan be affected by fertilizer which increases nitrates in the soilincreases nitrates in the soil soil N2 NO3
  • 77. Human Impact on Environment  Human population growingHuman population growing exponentially due to advances inexponentially due to advances in MedicineMedicine Food productionFood production  Large human population isLarge human population is affecting the environmentaffecting the environment
  • 78. Tracking Human Impact
  • 79. 1. Global warming  COCO22 increase in atmosphereincrease in atmosphere traps heat from suntraps heat from sun  COCO22 released by humanreleased by human activitiesactivities burning fossil fuelsburning fossil fuels IndustryIndustry CarsCars
  • 80. Global Warming and Ocean Pollution
  • 81. 2. Use of Pesticides  Can harm unintended organismsCan harm unintended organisms  Bioaccumulation/BiomagnificationBioaccumulation/Biomagnification causes increased amounts ofcauses increased amounts of lead and mercury in organismslead and mercury in organisms higher up in the food chainhigher up in the food chain
  • 82. 3. Humans affect Biodiversity  Habitat loss (gone)Habitat loss (gone)  Habitat fragmentation (smallerHabitat fragmentation (smaller areas)areas)  Introduction of exoticsIntroduction of exotics  Habitat degradationHabitat degradation Land pollutionLand pollution Water pollutionWater pollution Air pollutionAir pollution
  • 83. Population Sampling  Uses a small part of a larger populationUses a small part of a larger population to estimate the size of the largerto estimate the size of the larger populationpopulation  Saves timeSaves time  Saves costSaves cost  ConvenientConvenient
  • 84. How to do a Random Sample  Divide larger area into equally sizedDivide larger area into equally sized smaller areas.smaller areas.  Equally sized smaller areas are calledEqually sized smaller areas are called quadrats.quadrats.  Randomly select a quadrat (or smallerRandomly select a quadrat (or smaller area) and count the organisms found inarea) and count the organisms found in that space. Record this number.that space. Record this number.  Randomly select several more areasRandomly select several more areas and count the number of organismsand count the number of organisms found in the area and record totals.found in the area and record totals.
  • 85.  Average the number of organisms byAverage the number of organisms by dividing the total organisms counted individing the total organisms counted in the selected quadrats by the number ofthe selected quadrats by the number of quadrats counted.quadrats counted.  This average represents the averageThis average represents the average population size for each quadrat.population size for each quadrat.  The average number of organisms perThe average number of organisms per quadrat is then multiplied by thequadrat is then multiplied by the number of quadrats.number of quadrats.  This number represents the averageThis number represents the average number of organisms in the entire area.number of organisms in the entire area.