Population Ecology

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Population Ecology - Presentation Transcript

  1. Population Ecology
  2. Tuna Tracker In The News
  3. Ecology
    • Study of the interactions between organisms and the environment
    • Study of the physical and biological variables governing the distribution & growth of living things
  4. Population
    • Individuals of a given species occurring at one place at one time
    • Population ecology
      • Study of population growth & interactions
  5. Population Size
    • (births + immigrants) – (deaths + emmigrants) = Population change
    • Immigration – movement into a population
    • Emigration – movement out of a population
  6. Growth Rate
    • Subtract death rate from birth rate
    • r = b – d
      • r is growth rate
      • b is birth rate
      • d is death rate
    • Population growth = rN
      • N = initial population size
  7. Exponential Growth
    • Rate of increase remains constant
    • Population size soon increases greatly
    • Can only occur under ideal conditions
    • This type of growth cannot continue forever
  8. Exponential Growth of a Bacteria
  9. Carrying Capacity
    • Indefinite exponential growth is limited
    • Shortages of growth factors will limit population growth
    • Carrying capacity = maximum number that can be supported in a particular environment
  10. Sigmoid Growth Curve
    • Initial exponential growth and subsequent stabilization at carrying capacity
  11. Boom & Bust Cycle
    • Sometimes populations do not level off
    • Exponential growth with a sudden die-off
  12. Population Size & Ability to Survive
    • Very small populations are less able to survive than large populations
      • Random events can wipe out small populations
      • Small populations have less genetic variability
  13. Population Density
    • Number of organisms per unit area
    • Density influences survival
  14. Dispersion
    • Way that individuals are arranged
    • Three patterns
      • Uniform
      • Random
      • Clumped
  15. Uniform Distribution
    • Individuals evenly spaced
    • Often results from territoriality
    • Also plants with allelopathy
  16. Random Distribution
    • Lacking definite order
    • Individuals do not influence others growth
  17. Clumped Distribution
    • Individuals form clusters
    • Clumping due to interaction of individuals
  18. Density Dependent Factors
    • Factors that affect a population only if its density changes
    • Types of density dependent factors
      • Competition
      • Predation
      • Parasitism
  19. Competition
    • Interaction among organisms for the same resources
      • Food
      • Living space
    • Regulates population size & is a driving force of evolutionary change
  20. Competition Types
    • Intraspecific – among the same species
    • Interspecific – between species
  21. Predation
    • One species will kill & eat another
    • Interactions maintain natural populations
    • More prey results in more predators
    • Less prey reduces predator numbers
  22. Parasitism
    • One species living at the expense of another
    • Regulates populations by weakening or killing
  23. Density-Dependent Factors & Boom & Bust Cycles
    • Example:
      • Lemmings have large increases & declines
      • Lemming populations increase, then predators increase
      • Then, lemming populations are mostly eliminated causing predator populations to decrease because of lack of food
      • Then, lemming populations can increase….
  24.  
  25. Density-Independent Factors
    • Operates regardless of population density
    • Includes factors such as weather & physical disruptions
    • A certain percentage of the population will die due to the event
  26. Survivorship
    • Age distribution
      • Proportion of individuals that survive to an age category
      • Differs greatly from species to species
  27. Mortality vs. Survivorship
    • Mortality – death rate
    • Survivorship – proportion of an original population that survives to a certain age
  28. Type I Survivorship
    • Low infant mortality
    • Small number of offspring, parental care
    • Most survive to an old age
  29. Type II Survivorship
    • Often reproduce asexually
    • Mortality is constant over lifespan
  30. Type III Survivorship
    • High infant mortality
    • Those that survive are likely to live to old age
    • No parental care, high reproductive rate
  31. Demography
    • Statistical study of human population
    • Human population is in exponential growth
  32. Human Population Growth has Different Patterns
    • Stable population
      • Remains the same
      • Same number entering reproductive age as at end of reproductive age
    • Population pyramid
      • Graphic representation of population age
      • Shows patterns in population change
  33.  
  34. Population Growth in Developed Countries
  35. Population Growth in Developing Countries
  36. World Population distribution
  37. Share of the World Population
  38.  
  39. Interactions Within Communities
  40. Parasites Lost In The News
  41. Community
    • Grouping of populations living together in a particular area at a particular time
  42. Abiotic Factors
    • Nonliving factors within the environment
      • Air
      • Water
      • Rocks
    • Abiotic factors affect living (biotic) factors
  43. Ecosystem
    • Biotic & abiotic factors in a certain area
    • Community along with abiotic factors
  44. Habitat
    • Space within an area where an organism lives
    • Each organism plays a certain role
  45. Niche
    • Two ways of defining
      • An organism’s role in the environment
      • Organism’s use of biotic & abiotic resources
  46. Competition
    • Organisms that live near one another strive to obtain the same limited resource
    • Competitive exclusion principal
      • If 2 species are competing with one another for the same limited resource , the species able to use the resource most efficiently will eventually eliminate the other species
  47. Competition in Nature
    • Sage & grass both need the same soil nutrients
    • Sage out competes grass by secreting toxic chemicals
  48. Barnacle Competition
    • Balanus & chthamalus
      • Both live in the intertidal zone
      • This intertidal zone is their niche
  49. Fundamental Niche
    • Chthamalus can live out of water longer than Balanus
    • Fundamental niche
      • Everywhere a species can inhabit
  50. Realized Niche
    • When both species are present
      • Each actually lives where it competes best
      • This defines their realized niche
  51. Predation
    • Predator – kills & eats another species
    • Prey – eaten by another species
    • Predator-prey relationships affect each other’s populations
    • Several outcomes are possible
  52. Predator-Prey Example
    • Didnium – the predator
    • Paramecium – the prey
    • Predator & prey introduced into new environment
  53. Outcome 1
    • Predator exterminates prey
    • Predator then dies due to lack of food
  54. Outcome 2
    • Some prey hide in sediment
    • Predator eats those in clear fluid
    • Predator dies because it cannot find more food
  55. Outcome 3
    • Prey is introduced in successive intervals
    • Predator-prey follow cyclical pattern
  56. Plant –Herbivore Coevolutioin
    • Plants develop defenses against being eaten
    • Natural selection chooses animals able to feed on plants with new defenses
  57. Protective Adaptation
    • Some animals have adapted to eating plants that are toxic
    • Some (like monarch butterfly) are able to store toxins from food
    • Stored toxin protects the animal from predation
  58. Protective Coloration
    • Some highly poisonous organisms advertise with bright colors
    • Warning coloration is effective defense
  59. Mimicry
    • Unprotected species have come to resemble harmful or distasteful species
      • Batesian mimicry
      • Example: grasshopper that looks like a tiger beetle
  60. Mimicry
    • Protective coloration of different animals come to resemble each other
    • Both posses similar defenses
      • Mullerian mimicry
      • Example: Monarch & Viceroy butterflies
  61. Camouflage
    • Animal blends into its surroundings
    • Not seen by predators
    • Example: cabbage butterfly caterpillar
  62. Camouflage
  63. Symbiosis
    • One organism lives with another
    • Three types
      • Commensalism
      • Mutualism
      • Parasitism
  64. Termite Gut Symbiosis
  65. Commensalism
    • One species benefits
    • The other species neither benefits or is harmed
    • Examples: barnacles living on whales
  66. Mutualism
    • Both species benefit from relationship
    • Example: clownfish & anemones
  67. Mutualism
    • Red billed oxpeckers & impala
  68. Parasitism
    • One species benefits
    • One species is harmed
    • Example: humans & hookworms
  69. Plant Parasitism
  70. Succession
    • Change in communities over time
    • Generally linked to disturbance
  71. Primary Succession
    • Starts on surfaces not previously supporting organisms
    • Soil must accumulate
    • Pioneer community becomes established
      • Usually plants able to grow under harsh conditions
  72. Primary Succession
    • Pioneer community paves way for growth & development of native vegetation
    • Plant community changes through time
    • Eventually a climax community establishes
  73. Primary Succession Mount St. Hellens
  74. Succession of a Pond
  75. Secondary Succession
    • Areas with soil have been disturbed
    • Community does not start from no soil stage
    • Common due to human activity
  76.  
  77. Ecosystems
  78. Food of the Sea In The News
  79. Ecosystem
    • Includes abiotic environment & community
    • Types of organisms of an ecosystem
      • Producers
      • Consumers
      • Decomposers
  80. Producers
    • Make their own food
    • Base of the food chain
    • Plants & photosynthetic protists
  81. Consumers
    • Heterotrophs – feed on other organisms
    • Kill & eat their food
  82. Decomposers
    • Special group of consumers
    • Nourishment from dead matter
    • Recyclers
  83. An Ecosystem
  84. Ecosystem Boundaries
    • May or may not be distinct
  85. Transfer of Nutrients
    • Ultimate source of most energy is the sun
    • Green plants capture energy from the sun
    • Consumers eat producers & other consumers
    • Detritivores convert organic materials to nutrients usable by plants
  86. Trophic Levels
    • Feeding levels & transfer of energy
      • Producer
      • Primary consumer – feed on producer
      • Secondary consumer – eat primary consumer
      • Tertiary consumer – eat secondary consumer
  87. Food Chain
  88. Food Web
    • Many species do not strictly feed on one trophic level
    • Interactions become more complicated
    • Food web – group of interwoven food chains
  89.  
  90. Energy Flow Through Ecosystems
    • Most energy is lost & does not transfer to the next trophic level
    • Higher trophic levels must have fewer individuals
      • Next highest trophic level has about 1/10 th the number of individuals, biomass & energy
  91. Flow of Energy
  92. Numbers in Trophic Levels
  93. Biomass in Trophic Levels
  94. Energy in Trophic Levels
  95. Obtaining Substances for Life
    • Materials cycle through ecosystems
    • Reservoir –area with most of a material
    • Examples of ecosystem cycles
      • Water (hydrologic cycle)
      • Nitrogen
      • Phosphorus
      • Oxygen
      • Carbon
  96. Water Cycle
    • Most living things are primarily water
    • Life’s chemical reactions require water
    • 90% of water that reaches atmosphere comes from plant transpiration
    • Atmospheric water condenses
  97.  
  98. Water Cycle
    • Plants take up about 1000 kg of water to produce 1 kg of biomass
    • Groundwater provides ¼ of water used by humans in U.S.
    • 2% of U.S. groundwater is polluted
      • Industry
      • Pesticides
  99. Carbon Cycle
    • CO 2 found in atmosphere & oceans
    • Producers & some consumers incorporate carbon into organic molecules
    • Animals & combustion return carbon to atmosphere
  100.  
  101. Oxygen Cycling
    • Plants use CO 2 , release O 2
    • Consumers use O 2 , release CO 2
    • Some CO 2 is liberated by decomposition
  102.  
  103. Nitrogen Cycle
    • Important plant nutrient
    • Atmosphere is reservoir
    • Nitrogen fixing bacteria convert N 2 to ammonia
  104.  
  105. Phosphorus Cycle
    • Required plant nutrient
    • Soil has only small amounts
    • Animals obtain phosphorus by eating plants
  106.  
  107. End chapter 40
  108. Biomes & Life Zones
  109. Food for Thought In The News
  110. Biomes
    • Large ecosystems occurring over wide areas of land within specific climatic regions
    • Support communities of characteristic organisms
  111. Patterns that Determine Biomes
    • Amount of solar radiation
    • Global atmospheric circulation
    • Features of the earth (topography)
  112. Solar Energy
    • Some parts of earth receive more energy
    • Greater latitude, colder climate
  113. Circulation Patterns
    • Differential heating creates six coils of rising & falling air
    • Rotation of earth deflects winds
      • Trade winds of equator
      • Westerlies of middle latitudes
  114. Precipitation
    • Warm air rises & is cooled
    • Cool air holds less moisture
    • Warm air absorbs available moisture
  115. Shadow Effect
    • Air traveling up a mountain is cooled
      • Precipitation forms
      • Windward side is moist
      • Leeward side is arid
  116. Ocean Circulation
    • Ocean moves in great spiral patterns
    • These surface currents affect climate
      • Redistribute heat
  117. Climatic Regions Classify Biomes
    • Tropical rain forest
    • Savannas
    • Deserts
    • Temperate grasslands
    • Temperate deciduous forests
    • Taiga
    • Tundra
  118.  
  119. Elevation & Biomes
  120. Tropical Rain forests
    • High temperature & rainfall
      • 200 – 450cm/yr (80 – 175 in/yr)
      • Average 25 º C (77º F)
    • Found on both sides of the equator
  121. Rain Forests
    • Extensive canopy of plants
      • 2% of light reaches forest floor
      • Plants do not grow well on forest floor
    • Epiphytes grow on trees
    • Giant diversity of life
    • Poor soils, do not support agriculture
  122.  
  123. Savannas
    • Areas near the equator
    • High temperature, moderate rainfall
      • 90 – 150 cm/yr (35 – 60 in/yr)
  124. Savannas
    • Open grasslands, scattered shrubs & trees
    • Supports large number of grazing herbivores
    • Large number of plant eating invertebrates
  125.  
  126. Termite Mounds of Australia
  127. Deserts
    • Low precipitation
      • 25 cm/yr (10 in/yr) or less
    • 20 to 30 degrees north & south of equator
  128. Deserts
    • Organisms with adaptations
    • High diversity, small populations
    • Many nocturnal animals
  129.  
  130. Temperate Deciduous Forests
    • Distinct seasons
    • Trees are deciduous
    • Precipitation moderate
      • 75 – 150 cm/yr (30 – 60 in/yr)
  131. Temperate Deciduous Forests
    • Upper canopy of dominant trees
    • Animal life abundant in trees & forest floor
    • Includes many human population centers
  132.  
  133. Temperate Grasslands
    • Includes prairies & steppes
    • 25 – 75 cm/yr (10 – 30 in/yr) of precipitation
  134. Temperate Grasslands
    • Large quantities of perennial grass
    • No trees
    • Grazing animals & burrowing rodents
    • Rich soils
    • Many areas converted to agriculture
  135.  
  136. Taiga
    • Long cold winters
    • Little precipitation
      • Most is in summer
      • Plants go through life cycle in short amount of time
  137. Taiga
    • Cone bearing trees common
    • Many large mammals
  138.  
  139. Tundra
    • Found at the top of the world
    • Permanent ice
    • Low precipitation like deserts
  140. Tundra
    • Life is apparent in short summer
    • Grasses & sedges
  141. Fresh-water Ecosystems
    • Intertwined with terrestrial ecosystems
    • Includes only 2% of earth
    • Ponds & lakes, rivers & Streams
    • Different water depths have different communities
  142. Life Zones of a Lake
  143. Rivers & Streams
    • Characterized as an open ecosystem
    • Nutrients washed into water
      • Feeds heterotrophs
      • Autotrophs rare
  144. Estuaries
    • Freshwater meets saltwater
    • Producers are mostly algae & phytoplankton
    • Nutrients abundant
    • High diversity of organisms
  145.  
  146. Oceans
    • Covers nearly ¾ of Earth
    • Variety of habitats
      • Intertidal zone
      • Neritic zone
      • Open sea zone
  147. Intertidal Zone
    • Harsh environment for life
    • Tide rolls in & out
    • Abundant light for photosynthesis
      • Variety of producers
    • Different habitats based on substrate
      • Rocky shore
      • Sandy shore
  148. Rocky Shore
  149. Sandy Shore
  150. Neritic Zone
    • On continental shelf
    • Abundant plant & animal life
    • Includes coral reefs
  151. Open-sea Zone
    • Beyond continental shelf
    • Many diverse forms of life
  152. Regions of Open-sea
    • Photic
      • Light penetrates
      • Supports phytoplankton
    • Mesopelagic
      • No photosynthetic organisms
      • Water pressure increases
  153. Regions of Open-sea
    • Abyssal
      • Deep water
    • Benthos
      • Sea floor bottom
  154.  
  155. The Biosphere
  156. Shark Test In The News Click here to view video
  157. The Biosphere
    • The global ecosystem
    • Includes all life on Earth
  158. Nonrenewable Resources
    • Formed at a rate more slowly than they are consumed
    • Examples:
      • Coal
      • Oil
      • Copper
      • Iron
  159. Fuel Resources
    • Fossil fuels (nonrenewable)
      • Coal
      • Oil
      • Natural gas
    • Currently 77% of worlds energy supply
      • Coal 20%
      • Oil 36%
      • Natural gas 21%
  160. Nuclear Power
    • Nonrenewable, but large supplies
    • 2.2 lbs. produces as much electricity as 2200 tons of coal
    • Problems
      • Cost of building power plants
      • Disposal of radioactive waste
  161. Mineral Resources
    • Inorganic
    • Occur naturally
    • Present in fixed amounts
    • Supplies will eventually be used
  162.  
  163. Municipal Solid Waste
    • Many things thrown away
      • Paper
      • Food waste
      • Plastics
      • Metals
      • Rubber
      • Leather
      • Textiles
      • Glass
      • Wood
  164. Municipal Solid Waste
  165. Strategies to Conserve
    • Reduce consumption
    • Reuse some items
    • Recycling
    • Buying recycled goods
  166. Renewable Resources
    • Replace themselves over time
    • Renewable energy sources
      • Solar power
      • Water power
      • Wind power
      • Geothermal energy
      • Bioenergy
  167. Solar Power
    • Use of sun for heating or to produce electricity
    • Solar cells convert energy into electricity
    • May be major source of energy by 2030
  168. Water Power
    • Falling water drives turbines to produce electricity
    • Wave power uses energy in sea waves
    • Tidal power
    • Problems: high cost & unsteady rate
  169. Wind Power
    • Wind to generate electricity
    • U.S. may generate 10-20% of energy by 2030
  170. Geothermal Energy
    • Hot water or steam from within Earth
    • Uses
      • Directly for heating
      • Converted to electricity
  171. Bioenergy
    • Using living plants to produce energy
    • Types of bioenergy
      • Burning of wood
      • Decomposition of animal waste
        • Produce methane-rich gas
        • Produce electricity
      • Ethanol production from plants
  172. Pollution
    • Threatens the biosphere
    • Substances that physically or chemically change water
    • Types of contaminants
      • Infections agents
      • Runoff, drainage & hazardous waste dumps
      • Toxic substances
      • Thermal pollution
      • Solid waste
  173. Dumping Pollutants into Water
    • Point source – where they enter water
    • Non-point source – enter in various places
      • Sediments in runoff
        • Often from agriculture
      • Mine drainings
      • Poisons leaching from hazardous dumps
      • Pesticides, herbicides, & fertilizers
  174. Toxic Dump Threatening Groundwater
  175. Toxic Substances
    • Come from many sources
    • Most do not degrade
    • Biological concentration
      • Toxins accumulate in fatty tissues
    • Biological magnification
      • Amounts increase in food chain
  176. Biological Magnification of DDT
  177. Pollution from Organic Nutrients
    • Common sources
      • Sewage treatment plants
      • Paper mills
      • Meat packing plants
    • Food for bacteria that grow in water
    • Decreases oxygen in waters
  178. Pollution from Inorganics
    • Common sources
      • Croplands
      • Laundry detergents
    • Can lead to eutrophication
      • Heavy plant growth
      • Plants die
      • Bacteria decompose plants, use oxygen
  179. Mismanagement of Solid Waste
    • Sanitary landfills help, but problems still exist
      • Space is running out
      • Groundwater contamination is possible
  180. Air Pollution Sources
  181. Burning Fossil Fuels
    • Major source of air pollution
    • Causes smog or grey air
  182. Secondary Pollutants
    • Sun causes reactions with chemicals in air
    • New pollutants are created
    • Ozone is principal secondary pollutant
      • Irritating to eyes & respiratory system
  183. Ground Level Ozone in U.S. Cities
  184. Acid Rain
    • Caused by precipitation in polluted air
    • pH of waters are lowered
  185. Acid Rain Effects
    • Acidifies lakes
      • Kills aquatic life
    • Leaching of metals
    • Eats away stone
    • Kills plants
  186. Acid Rain Effects
  187. Damage to Ozone Level
    • Ozone in stratosphere shields UV rays
    • Main source of damage is chlorofluorocarbons
  188. Deforestation
    • 2% of Earth (rainforests) has 50% of plants & animals
      • Contribute to 25% of medicines
    • Plays important role in worlds climates
  189. Deforestation
    • Population & poverty is high
    • Logging & farming efforts reduce forests
      • Poor soils do not support agriculture for long
  190. Forest Conservation
    • Reserves are a partial answer
  191. Global Warming
    • High CO 2 levels block outward heat radiation
      • Creates greenhouse effects
    • Other gases contribute
      • Methane
      • Nitrogen oxides
  192. Species Extinction
    • Factors threatening species
      • Habitat destruction
      • Pollution
      • Illegal trade
    • Results in reduction of biological diversity
  193. Value of Biological Diversity
    • Elimination of species affects other species
    • Sources of food, medicine, …
    • Less diversity in crops means more vulnerability
  194.  
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