1. Population Dynamics Chapter 35

2. Population Dynamics Key concepts include: interactions within and among populations including carrying capacities, limiting factors, and growth curves;

3. Population: all the individuals of a species that live together in an area

4. Three Key Features of Populations Size Density Dispersion  (clumped, even/uniform, random)

5. Three Key Features of Populations 1. Size: number of individuals in an area

6. Estimating Population Mark – Recapture – used to estimate animal population

7. Mark Recapture Capture an initial sample, count and mark them Release the marked individuals Capture and count another sample count marked individuals recaptured

8. Formula (1 st sample x 2 nd sample) Number recaptured

9. Example: Mark - Recapture 100 ants are captured, marked and released. 90 ants are captured in the 2 nd sample. 8 of the ants in the 2 nd sample were marked. 100 x 90 = 9000=1125 ants 8 8

10. Sample Plot – used to estimate plant populations

11. Sample Plot Randomly chosen plots are selected and populations counted and averaged. Randomly chosen plots are selected and populations counted and averaged. The average is used to estimate the total population The average is used to estimate the total population

12. Example 6 4 8 2 3 8+4+6+3+2 = 23 23 = 4.6 5 4.6 x 100 = 460

13. Three Key Features of Populations 2. Density: measurement of population per unit area or unit volume Formula: Dp= N S Pop. Density = # of individuals ÷ unit of space

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18. Three Key Features of Populations 3. Dispersion: describes their spacing relative to each other  clumped  even or uniform  random

19. clumped even (uniform) random

20. Population Dispersion

24. Exponential Growth ideal, unregulated population growth Produces a J shaped curve

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26. After 4 days, $ 0.16 vs. $ 20,000

27. After 8 days, $ 2.55 vs. $ 40,000

28. 9 2.565,000 10 5.125,000 11 10.245,000 1220.485,000 Total$40.95$60,000 Total$40.95$60,000 1340.965,000 1481.925,000 15163.845,000 16327.685,000 Total$655.35$80,000 Total$655.35$80,000

29. 17 655.365,000 181310.725,000 192621.445,000 205242.885,000 Total$10,485.75 $100,000 Total$10,485.75 $100,000

30. 2110,485.765,000 2220,971.525,000 2341,943.045,000 2483,886.085,000 Total $167,772.15$120,000 Total $167,772.15$120,000

31. 25167,772.165,000 26335,544.325,000 27671,088.645,000 281,342,177.285,000 292,684,354.565,000 305,368,709.125,000 Total$10,737,418.23$150,000 Total$10,737,418.23$150,000

33. Factors that affect populations Limiting factor- any biotic or abiotic factor that restricts the existence of organisms in a specific environment.  EX.- Amount of water Amount of food Temperature

34. Factors that limit populations Density-dependent factors- Biotic factors in the environment that have an increasing effect as population size increases Ex. disease competition (food supply) parasites predators

35. Density-independent factors- Abiotic factors in the environment that affect populations regardless of their density Ex. temperature fire habitat destruction drought Factors that affect density

36. Carrying Capacity- the maximum population size that can be supported by the available resources There can only be as many organisms as the environmental resources can support

37. Logistic Growth Ideal growth that is slowed by limiting factors as the population increases Produces an S shaped curve

38. Carrying Capacity Carrying Capacity (k) NumberNumber Time J-shaped curve (exponential growth) S-shaped curve (logistic growth)

41. Boom and Bust Cycles Some populations fluctuate with regularity

43. Life History The series of events from birth, through reproduction to death

44. 2 Life History Patterns 1. R Strategists  short life span  small body size  reproduce quickly  have many offspring  little parental care  Ex: cockroaches, weeds, bacteria

45. R strategist These organisms produce as many offspring as possible. Invest little in each offspring. In good conditions, populations explode Good strategy for unpredictable environments

47. 2 Life History Patterns 2. K Strategists  long life span  large body size  reproduce slowly  have few young  provides parental care  Ex: humans, elephants

48. K strategists These organisms produce few offspring and invest resources, time and their own safety to ensure survival of offspring Good strategy for stability K= carrying capacity

50. Demography the statistical study of populations, make predictions about how a population will change

51. 1. Immigration- movement of individuals into a population 2. Emigration- movement of individuals out of a population Movement of Populations

52. Immigration Emigration Natality Mortality Population + + - - Factors That Affect Future Population Growth

53. Key Features of Populations Growth Rate: Birth Rate (natality) - Death Rate (mortality) How many individuals are born vs. how many die Birth rate (b) − death rate (d) = rate of natural increase (r).

54. PRE- REPRODUCTIVE REPRODUCTIVE POST- REPRODUCTIVE

55. Population of a Stable Country

59. Demographic Transition The movement from high birth and high death rate to low death rate then lower birth rate

60. Human Population Growth

63. Time unitBirthsDeaths Natural increase Year 130,013,274 56,130,242 73,883,032 Month 10,834,440 4,677,520 6,156,919 Day 356,201153,781 202,419 Hour 14,8426,408 8,434 Minute 247 107141 Second 4.11.8 2.3

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65. Chapter 36 Ecosystem Structure and Dynamics

66. Biodiversity The number of different species in a community

67. Competition Interspecific competition – two species compete for the same resource

68. Niche is how an organism makes its living, or how it uses resources  What it eats  Its habitat

69. Competitive Exclusion When two species occupy the same niche, one is displaced

70. Resource partitioning In order for two species to inhabit the same area, they divide resources

71. Symbiotic Relationships Symbiosis- two species living together 3 Types of 1. Commensalism 2. Parasitism 3. Mutualism

72. Symbiotic Relationships Commensalism- one species benefits and the other is neither harmed nor helped Ex. orchids on a tree

73. Symbiotic Relationships Commensalism- one species benefits and the other is neither harmed nor helped Ex. polar bears and cyanobacteria

74. Symbiotic Relationships Parasitism- one species benefits (parasite) and the other is harmed (host) Parasite-Host relationship

75. Symbiotic Relationships Parasitism- parasite-host Ex. lampreys, leeches, fleas, ticks, tapeworm

76. Symbiotic Relationships Mutualism- beneficial to both species Ex. cleaning birds and cleaner shrimp

77. Symbiotic Relationships Mutualism- beneficial to both species Ex. lichen

79. Type of relationship Species harmed Species benefits Species neutral Commensalism Parasitism Mutualism = 1 species

80. Trophic Levels Each link in a food chain is known as a trophic level. Trophic levels represent a feeding step in the transfer of energy and matter in an ecosystem.

81. Herbivores – eat only producers Cows, Deer, Horses, Grasshoppers Carnivores – eat only the flesh of other animals Wolves, Tigers, Bass, Orca

82. Detritovores – eat only dead organisms or wastes Vultures, Carrion Beetles Omnivores – eat both animals and plants Bears, Pigs, Humans

83. Trophic Levels Biomass- the amount of organic matter comprising a group of organisms in a habitat. As you move up a food chain, both available energy and biomass decrease. Energy is transferred upwards but is diminished with each transfer.

84. Energy Lost 90% is lost as heat 10% is passed on to the next level

85. Trophic Levels Producers- Autotrophs Primary consumers- Herbivores Secondary consumers- small carnivores Tertiary consumers- top carnivores ENERGYENERGYE E E

88. Trophic Levels Food chain- simple model that shows how matter and energy move through an ecosystem

90. Trophic Levels Food web- shows all possible feeding relationships in a community at each trophic level Represents a network of interconnected food chains

91. Food chainFood web (just 1 path of energy) (all possible energy paths)

96. Nutrient Cycles Cycling maintains homeostasis (balance) in the environment. 3 cycles to investigate:  1. Water cycle  2. Carbon cycle  3. Nitrogen cycle

97. Water cycle- Evaporation – liquid to gas Transpiration- evaporation through leaves of plants Condensation- gas to liquid Precipitation- snow, rain, etc.

98. Water cycle-

99. Carbon cycle- Photosynthesis and respiration cycle carbon and oxygen through the environment.

100. Carbon cycle-

101. Photosynthesis Energy + CO 2 + H 2 O  C 6 H 12 O 6 + O 2 Cellular Respiration C 6 H 12 O 6 + O 2  Energy + CO 2 + H 2 O

102. Nitrogen cycle- Atmospheric nitrogen (N2) makes up nearly 78%-80% of air. Organisms can not use it in that form. Lightning and bacteria convert nitrogen into usable forms.

103. Nitrogen cycle- Only in certain bacteria and industrial technologies can fix nitrogen. Nitrogen fixation -convert atmospheric nitrogen (N 2 ) into ammonium (NH 4 + ) which can be used to make organic compounds like amino acids. N 2 NH 4 +

104. Nitrogen cycle- Nitrogen-fixing bacteria: Some live in a symbiotic relationship with plants of the legume family (e.g., soybeans, clover, peanuts).

105. Some nitrogen-fixing bacteria live free in the soil. Nitrogen-fixing cyanobacteria are essential to maintaining the fertility of semi-aquatic environments like rice paddies.

107. Atmospheric nitrogen Lightning Nitrogen fixing bacteria Ammonium Nitrification by bacteria NitritesNitrates Denitrification by bacteria Plants Animals Decomposers Nitrogen Cycle

108. Toxins in food chains- While energy decreases as it moves up the food chain, toxins increase in potency. This is called biological magnification

109. Succession- a series of changes in a community in which new populations of organisms gradually replace existing ones

110. Primary succession- colonization of new sites by communities of organisms – takes place on bare rock

111. Primary succession- New bare rock comes from 2 sources:  1. volcanic lava flow cools and forms rock

112. Primary succession- New bare rock comes from 2 sources:  2. Glaciers retreat and expose rock

113. Pioneer species- the first organisms to colonize a new site  Ex: lichens are the first to colonize lava rocks

114. Primary Succession- Rock

115. Climax community- a stable, mature community that undergoes little or no succession

116. Primary succession-

117. Secondary succession- sequence of community changes that takes place when a community is disrupted by natural disaster or human actions – takes place on existing soil

118. Secondary succession- Ex:  fire

119. Secondary succession- Ex:  farming

120. Secondary succession-