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Chapter 3 Communities, Biomes and Ecosystems

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Title: Chapter 3 Communities, Biomes and Ecosystems


1
Chapter 3 Communities, Biomes and Ecosystems
2
1. Life in a community
3
  • Every ecosystem has a tendency to change from
    simple to complex. A final , stable community
    will become established ( climax community)
  • What grows and survives varies

4
Limiting Factors
  • Factors that affect an organisms ability to
    survive in its environment.
  • (any condition that keeps the size of a
    population from increasing)
  • May be abiotic or biotic
  • Fig. 3.1 trees at timberline

5
Tolerance
  • All organisms have a range of tolerance for
    different conditions.

6
Tolerance
  • Ability to withstand fluctuations in A or B
    Factors.

7
Ecological Succession
  • 2 kinds
  • Primary
  • Secondary

8
Ecological Succession
  • Change in the composition of species that make up
    a community over time.
  • Orderly
  • Natural
  • Occurs in stages
  • Can take decades or centuries

9
2. Types of Ecological Succession
  • 1. Primary succession
  • The collinization of barren land.

10
Primary Succession
  • First lifeOn barren rock or ice.
  • Such as newly formed volcanic island. sand
    dune
  • First org. to establish
  • Pioneer Species
  • Often are Lichens
  • (bacteria fungus, OR algae fungus)

11
Lichens
12
Pioneer Species
  • First plants on Barren rocks.
  • Lichens, small plants with brief life cycles
  • Improve conditions.

13
Primary Succession continued
  • Soil develops gradually
  • grasses overtake the lichens then ferns then
    shrubs and trees.
  • Eventually the land
  • is colonized by plants that become the main
    vegetation.
  • ..The Climax Community

14
Succession
15
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16
2. Secondary Succession
  • Occurs after
  • existing community cleared by a disturbance.
  • Occurs where
  • the soil is intact
  • For example following a fire

17
Secondary
18
Eventually
  • A stable community is established.a Climax
    Community
  • Influenced by 2 factors
  • Temperature
  • And
  • Rainfall

19
Climax Community
  • Stable array of species that persists relatively
    unchanged over time.

20
Stages of Secondary Succession
21
Forests
22
Hot Spots
  • Portions of biomes that show the greatest
    biodiversity
  • Conservationists are working to inventory and
    protect these regions
  • 24 hot spots hold more than half of all
    terrestrial species

23
Fig. 44.6, p. 760
24
Biomes
  • Terrestrial
  • Aquatic
  • Marine
  • Estuary
  • Freshwater

25
3.2 Terrestrial Biomes
  • Climate results from uneven heating
  • The average weather conditions in an area
  • Latitude
  • More direct sunlight at equator
  • Elevation
  • Ocean currents
  • Land masses

26
Major Terrestrial Biomes
  • Characterized by Latitude and Climate
  • Tundra
  • Boreal Forest (Tiaga) (pine trees)
  • Temperate Forest ( deciduous trees)
  • Temperate woodland and shrubland ( example
    chaparrel)
  • Temperate Grassland
  • Desert
  • Tropical Savanna
  • Tropical Dry ( Seasonal) Forest
  • Tropical Rain Forest

27
Tundra
  • The tundra is cold year-roundit has short cool
    summers and long, severe winters.  Drainage is
    poor
  • permafrost
  • little precipitation, about 4 to 10 inches per
    year, and what it does receive is usually in the
    form of snow or ice.    There is little diversity
    of species.  Plant life is dominated by mosses,
    grasses, and sedges

28
Tundra
  • Below polar ice caps
  • Treeless
  • Permafrost
  • Shallow-rooted vegetation
  • Plants are low, cushiony mats
  • lichens
  • Cold and dark most of the year

29
A,b arctic c is alpine
Fig. 44.19, p. 771
30
Boreal Forest (Taiga)
  • Below Tundra
  • Pine trees
  • Short, moist summers
  • Moose, deer

31
The Taiga
  • Also know as boreal forests, the taiga is
    dominated by conifers (cone-bearing plants), most
    of which are evergreen (bear leaves throughout
    the year).  The taiga has cold winters and warm
    summers. 
  • The soil is acidic and mineral-poor.  It is
    covered by a deep layer of partially-decomposed
    conifer needles.

32
Temperate Deciduous Forest
  • Four distinct seasons
  • Hot in the summer to below freezing in the
    winter. 
  • Rain is plentiful
  • Deciduous trees -drop their leaves in the autumn,
  • Broad-leaf deciduous trees
  • 4 seasonshot summers, cold winters
  • Deer, rabbits, squirrels, oak trees, maple trees

33
Tropical Rain Forest
  • Warm, uniform temps
  • Large amounts of rain throughout the year (
    125-660 cm/yr)
  • Vertically layered
  • epiphytes

34
Tropical rainforest
  • Highest species diversity (species rich
  • Amazon rainforests produce about
  • 40 of the world's oxygen
  • One in four pharmaceuticals comes from a plant in
    the tropical rainforests

35
Tropical Rainforest
  • Plants grow rapidly /use up nutrients.
  • This results is a soil that is poor. 
  • The tropical rainforest is Dense/not much
    sunlight reaches the forest floor. 
  • Adaptations
  • Specialized roots help hold up plants in the
    shallow soil
  • some plants climb on others to reach the sunlight
  • smooth bark and smooth or waxy flowers speed the
    run off of water
  • plants have shallow roots to help capture
    nutrients from the top level of soil.

36
Fig. 44.6, p. 760
37
Grassland
  • Extremely rich soil
  • b/c grasses die off annually
  • Well-suited to agriculture
  • The Breadbasket of the World
  • 2 General Kinds

38
Temperate Grassland
  • Fertile soil
  • Thick cover of grasses
  • No trees
  • Maintained by periodic fires and animal grazing

39
Tropical Savanna
  • Grasses and Scattered Trees
  • Africa, s. America, Australia
  • Hot rainy summers
  • Winters- cool dry

40
Deserts
  • All continents except Europe
  • Annual rate of evaporation exceeds rate of
    precipitation
  • Less than 26 centimeters annual rainfall
  • One third of land surface
  • Nocturnal animals
  • Plants adapted

41
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42
Desert
  • Some plant adaptations.
  • Some plants, called succulents, store water in
    their stems or leaves
  • Long root systems.
  • Waxy coating on stems and leaves help reduce
    water loss.
  • Flowers that open
  • Nocturnal animals

43
Aquatic Ecosystems
  • Grouped based upon abiotic factors
  • Freshwater
  • Transitional
  • marine

44
Freshwater
  • Rivers Streams
  • Water movement varies
  • More plants where water is slow
  • Fish feed here

45
Lakes ponds
  • Bodies of standing freshwater
  • Temperature varies with season
  • So does oxygen nutrients
  • Highest in Autumn and Spring

46
Transition Aquatic Ecosystems
  • Estuary

47
Estuary
  • Partially enclosed area where saltwater and
    freshwater mix
  • High species diversity
  • Important spawning area and nurseries
  • Dominated by salt-tolerant plants-algae, seaweed,
    marsh grass
  • Lots of waterfowl feed and migrating
  • Examples are Chesapeake Bay, San Francisco Bay,
    salt marshes of New England

48
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49
Marine Biomes
  • Zonation
  • Photic Zone
  • Aphotic Zone

50
Marine Biomes
  • Estuaries
  • Effects of Tides
  • Intertidal Zone
  • Animal adaptations here
  • In the Light
  • In the Dark

51
Alpine Tundra
  • Occurs at high elevations throughout the world
  • No underlying permafrost
  • Plants are low, cushions or mats as in arctic
    tundra

52
Chapter 4 Population Biology
  • How do populations grow?
  • What factors inhibit the growth of populations

53
4.1 Population DynamicsLearning Objectives
  • Population Dynamics
  • What is a population?
  • Compare patterns of Population growth
  • 2 Models
  • 1. Exponential Growththe J-curve
  • 2. Logistic Growth-The S-Curve
  • Describe life-history pattern and compare this to
    graphic representations
  • Be able to make predictions as to the effect of
    environmental factors on population growth.

54
  • How fast do populations grow?

55
Population Growth Rate
  • How Fast the population is growing
  • 2 most important
  • Birth Rate Natality
  • Death Rate Fatality
  • also
  • Immigration
  • Emigration

56
Exponential Growth
  • Unchecked growth
  • When no limits are put on the growth rate
  • J-shaped Curve
  • All populations grow at this rate until some
    limiting factor slows the growth rate.

57
Exponential Growth
  • Fastest rate of growth, under ideal conditions.
  • Unchecked Growth
  • Initially slow, then speeds up and remains rapid.
  • The larger the population becomes, the faster it
    grows!
  • J-Curve (if graphed the rate)
  • Examples Houseflies, Bacteria

58
Exponential Growthunlimited resources
59
Exponential growth J-CurveThe larger the
population gets, the faster it grows.
  • Aphidsplentiful food, room.

60
What limits population growth?
  • Limiting Factors
  • food, predation, disease, lack of space
  • Carrying Capacity
  • Maximum of a species an environment supports
    indefinitely.

61
Logistic Growth S-shaped curve
  • Pop. growth rate slows or stops at the
    populations carrying capacity.
  • Occurs when number of births is less than deaths
    OR when emigration exceeds immigration.

carrying capacity
Time
62
Copy this picture into your notes, including
labeling.(K is usually used to reference
carrying capacity
63
Reproductive Pattern
  • Reproductive pattern
  • Determines a populations growth.
  • 2 generalized patterns
  • rate-strategy ( r-strategy)
  • K-strategy

64
Reproductive Patterns
  • R-Strategy Rate Strategists
  • This is an adaptation to living in where
    fluctuations in biotic or abiotic factors occurs
  • Example mosquitoes
  • Changeable or unpredictable environments.
  • Populations are controlled by Density-Independent
    factors
  • Organisms characteristics
  • Small body size
  • Short life span
  • Mature rapidly
  • Reproduce early
  • Large numbers of offspring
  • Few survive

65
K-Strategists
  • Live in predictable environments
  • So, the carrying capacity of the environment
    changes little from year to year.
  • Example elephants and most large mammals, trees
  • Organisms characteristics
  • Stable environment
  • Slow rate of reproduction
  • Produce few offspring
  • Many survive
  • Offspring mature slowly
  • Care for their young
  • Maintain pop. sizes at or near carrying capacity
  • Populations controlled by Density-dependent
    factors

66
Population Dispersal Patterns
  • The pattern of spacing of individuals within an
    area.
  • 3 main patterns of dispersal
  • Uniform black bears ( territorial)
    fish-schools (safety good for predation)
  • Clumped Most common pattern
  • herds of grazing animals, such as American Bison
  • Random dandelions

67
How organisms are dispersedclumped most common
68
Population Density
  • The NUMBER of individuals in a given area.

69
2 Kinds of Limiting Factors related to dispersal
patterns.
  • 1. Density-dependent Factors
  • Often biotic factors
  • Exert a greater influence the larger the
    population gets.
  • EX disease, parasites, competition, predators
  • 2. Density Independent Factors
  • Affect a population regardless of their density
  • Most are abiotic factors
  • Ex Volcano, temperature, storms

70
  • ..\Bio 1\World Population.htm

71
1999
1975
domestication of plants, animals 9000 B.C.
(about 11,000 years ago)
agriculturally based urban societies
beginning of industrial, scientific revolutions
Fig. 40.9, p. 695
72
Chapter 5 Biodiversity and Conservation
73
  • Biodiversity
  • Genetic diversity
  • Species diversity
  • Ecosystem diversity

74
Dead as a Dodo
  • Flightless bird that lived on the island of
    Mauritius
  • Killed off by Europeans
  • Once the dodo was extinct, a tree native to
    Mauritius stopped reproducing

75
Biodiversity Extinction
  • 90 percent of all species that have ever lived
    are now extinct
  • Biodiversity is greater than ever
  • Current range of biodiversity is the result of
    past extinctions and recoveries

76
Importance of Biodiversity
77
5.2 Threats to Biodiversity
  • Extinction Rates
  • Background Extinction
  • Mass Extinctions

78
Humans and Mammalian Diversity
  • Humans began hunting mammals about 2 million
    years ago
  • About 11,000 years ago, they began to drastically
    reduce mammalian habitats
  • Of the 4,500 living mammal species, 300 (6.7
    percent) are endangered

79
  • Extinction
  • Endangered Species
  • Threatened
  • Introduced Species

80
Endangered Species
  • An endemic species that is extremely vulnerable
    to extinction
  • Endemic means a species originated in one
    geographic region and is found nowhere else

81
Threatened Regions
Critically endangered species
Threatened species
Relatively stable species populations intact
82
Indicator Species
  • Species that provide warning of changes in
    habitat and impending widespread loss of
    biodiversity
  • Example
  • Migratory birds that breed in N. America and
    winter over in tropical forests
  • Study found populations are plummeting as a
    result of deforestation, habitat fragmentation

83
Factors that Threaten Biodiversity
  • Habitat LossNumber one
  • Tropical Rain Forest
  • Coral Reefs
  • Overexploitation
  • Habitat Fragmentation
  • Pollution
  • Biological Magnification
  • Acis Precipitation
  • Eutrophication (cultural)

84
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85
DDT in Food Webs
  • Synthetic pesticide banned in the United States
    since 1970s.
  • Top carnivore birds accumulated DDT in their
    tissues.

86
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87
Shells are soft, crack, babies die.
88
DDT banned in US in 1972!
89
Habitat Loss Threats to Coral Reefs
  • Natural threats, such as hurricanes
  • Man-made threats
  • Water pollution, oil spills
  • Dredging
  • Dynamite and cyanide fishing
  • Coral bleaching

90
Habitat Loss
  • In the U.S.
  • 98 percent of tallgrass prairies are gone
  • 50 percent of wetlands have been destroyed

91
Coral Bleaching
  • Reef-building corals have photosynthetic,
    dinoflagellate symbionts
  • When stressed, corals expel the protistans
  • If the stress persists, the coral will die,
    leaving only its bleached hard parts behind
  • Coral bleaching may be an effect of global
    warming and increased sea temperatures

92
Habitat Fragmentation
  • Habitats are chopped up into patches
  • Three effects
  • Increases habitat edges
  • Decreases number of individuals that can be
    supported may be too few to allow breeding
  • Decreases the area in which individuals can find
    food or other resources

93
Habitat Degradation
94
Introduced Species
  • Species that have been introduced into a habitat
  • either deliberately or accidentally
  • No natural enemies or controls
  • Can outcompete native species
  • Play a role in 70 percent of cases where endemic
    species are threatened

95
Nile Perch in East Africa
  • Nile perch were introduced into Lake Victoria as
    a food source
  • This predator ate native cichlids drove many
    species to extinction
  • Now Nile perch species is close to crashing

96
Rabbits in Australia
  • Rabbits were introduced for food and hunting
  • Without predators, their numbers soared
  • Attempts at control using fences or viruses have
    thus far been unsuccessful

97
Kudzu in Georgia
  • Imported for erosion control
  • No natural herbivores, pathogens, or competitors
  • Grows over landscapes and cannot be dug up or
    burned out
  • May turn out to have some commercial use

98
5.3 Conservating Biology
99
Rachel Carson
  • Oceanographer and marine biologist
  • Published Silent Spring in 1962
  • Described the harmful effects of pesticides on
    songbirds and other species
  • Book helped launch the environmental movement

100
Conservation Biology
  • Systematic study of biodiversity
  • Works to elucidate the evolutionary and
    ecological origins of biodiversity
  • Attempts to identify ways to maintain
    biodiversity for the good of human populations

101
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102
Density-Dependent Controls
  • Logistic growth equation deals with
    density-dependent controls
  • Limiting factors become more intense as
    population size increases
  • Disease, competition, parasites, toxic
    effects of waste products

103
Density-Independent Controls
  • Factors that affect population growth regardless
    of population density.
  • Natural disasters or climate changes affect large
    and small populations alike

104
Age Structure Diagrams
  • Show age distribution of a population

SLOW GROWTH
ZERO GROWTH
NEGATIVE GROWTH
RAPID GROWTH
105
Pollutants
  • Substances with which an ecosystem has had no
    prior evolutionary experience.
  • No adaptive mechanisms are in place to deal with
    them

106
Air Pollutants
  • Carbon oxides
  • Sulfur oxides
  • Nitrogen oxides
  • Volatile organic compounds
  • Photochemical oxidants
  • Suspended particles

107
Industrial Smog
  • Gray-air smog
  • Forms over cities that burn large amounts of coal
    and heavy fuel oils mainly in developing
    countries
  • Main components are sulfur oxides and suspended
    particles

108
Photochemical smog
  • Brown-air smog
  • Forms when sunlight interacts with components
    from automobile exhaust
  • Nitrogen oxides are the main culprits
  • Hot days contribute to formation

109
Thermal Inversion
  • Weather pattern in which a layer of cool, dense
    air is trapped beneath a layer of warm air

cool air
warm inversion air
cool air
110
Acid Deposition
  • Caused by the release of sulfur and nitrogen
    oxides
  • Coal-burning power plants and motor vehicles are
    major sources

111
Ozone Thinning
  • In early spring and summer ozone layer over
    Antarctica thins
  • Seasonal loss of ozone is at highest level ever
    recorded

112
Effect of Ozone Thinning
  • Increased amount of UV radiation reaches Earths
    surface
  • UV damages DNA and negatively affects human
    health
  • UV also affects plants, lowers primary
    productivity

113
Protecting the Ozone Layer
  • CFC production has been halted in developed
    countries, will be phased out in developing
    countries
  • Methyl bromide will be phased out
  • Even with bans it will take more than 50 years
    for ozone levels to recover

114
Generating Garbage
  • Developed countries generate huge amounts of
    waste
  • Paper products account for half the total volume
  • Recycling can reduce pollutants, save energy,
    ease pressure on landfills

115
Land Use
  • Almost 21 percent of Earths land is used for
    agriculture or grazing
  • About half the Earths land is unsuitable for
    such uses
  • Remainder could be used, but at a high ecological
    cost

116
Green Revolutions
  • Improvements in crop production
  • Introduction of mechanized agriculture and
    practices requires inputs of pesticides,
    fertilizer, fossil fuel
  • Improving genetic character of crop plants can
    also improve yields

117
Deforestation
  • Removal of all trees from large tracts of land
  • 38 million acres logged each year
  • Wood is used for fuel, lumber
  • Land is cleared for grazing or crops

118
Effects of Deforestation
  • Increased leaching and soil erosion
  • Increased flooding and sedimentation of
    downstream rivers
  • Regional precipitation declines
  • Possible amplification of the greenhouse effect

119
Regions of Deforestation
  • Rates of forest loss are greatest in Brazil,
    Indonesia, Mexico, and Columbia
  • Highly mechanized logging is proceeding in
    temperate forests of the United States and Canada

120
Reversing Deforestation
  • Coalition of groups dedicated to saving Brazils
    remaining forests
  • Smokeless wood stoves have saved firewood in
    India
  • Kenyan women have planted millions of trees

121
Destroying Biodiversity
  • Tropical rainforests have the greatest variety of
    insects, most bird species
  • Some tropical forest species may prove valuable
    to humans
  • Our primate ancestors evolved in forests like the
    ones we are destroying

122
Desertification
  • Conversion of large tracts of grassland to
    desertlike conditions
  • Conversions of cropland that result in more than
    10 percent decline in productivity

123
The Dust Bowl
  • Occurred in the 1930s in the Great Plains
  • Overgrazing and prolonged drought left the ground
    bare
  • 1934 winds produced dust storms that stripped
    about 9 million acres of topsoil

124
Ongoing Desertification
  • Sahel region of Africa is undergoing rapid
    desertification
  • Causes are overgrazing, overfarming, and
    prolonged drought
  • One solution may be to substitute native
    herbivores for imported cattle

125
Water Use and Scarcity
  • Most of Earths water is too salty for human
    consumption
  • Desalinization is expensive and requires large
    energy inputs
  • Irrigation of crops is the main use of freshwater

126
Negative Effects of Irrigation
  • Salinization, mineral buildup in soil
  • Elevation of the water table and waterlogging
  • Depletion of aquifers

127
Ogallala Aquifer
  • Extends from southern South Dakota to central
    Texas
  • Major source of water for drinking and irrigation
  • Overdrafts have depleted half the water from this
    nonrenewable source

128
Water Pollutants
  • Sewage
  • Animal wastes
  • Fertilizers
  • Pesticides
  • Industrial chemicals
  • Radioactive material
  • Excess heat (thermal pollution)
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