Transcript big idea 4 ecology concepts

Ecology
AP Biology
Ecology
• Scientific study of the interactions
between organisms and their
environment
Levels of Study
• Organism
– Individual
– 1 turtle
Levels of Study
• Population
• Individuals of
the same
species living in
the same area
• All the turtles of
the same
species
Levels of Study
• Community
• All the organisms
living in an area
• All the turtles,
plants, insects,
algae, bacteria
Levels of Study
• Ecosystem
• All the organisms
and all the
abiotic factors
• All the organisms
& the soil, water,
gases, minerals
Levels of Study
• Biosphere
• All the
organisms & all
the abiotic
factors on
Earth
• Earth
Abiotic Factors
• Nonliving
• Temperature
• Climate
• Soil type
• Rainfall
• Gases
• Minerals
Biotic Factors
• Living
• Predators
• Parasites
• Herbivores
• Carnivores
• Decomposers
Biomes
• Tropical rainforest
• Tall trees
• High temperature
• Heavy rainfall
Biomes
•
•
•
•
•
•
Savannas
Tropical
Grasslands
Scattered trees
High temperature
Less rainfall than
tropical rain forest
Biomes
• Temperate grasslands
• Grasses
• Seasonal droughts
• Occasional fires
• Lower temperature &
less rainfall than
savannas
Biomes
• Deciduous forests
• Deciduous trees
• Oak, maple
• Warm summers
• Cold winters
• Moderate rainfall
Biomes
• Taiga
• Coniferous forests
• Pines & firs
• Cold winters
• Heavy snowfall
Biomes
• Tundra
• Grasses & sedges
• Very cold winters
• Permafrost
• High winds
• Little rain
Population Ecology
• Refer to written notes as you go
through the slides
Population
• Definition:
– Group of individuals:
• Of same species
• Living in same area
• Using the same resources
• Responding to same stimuli
Population Characteristics
• Density
• Number of
individuals per unit
area or volume
Population Characteristics
• Dispersal Patterns
• Spacing between
individuals
• Clumped
• Uniform
• Random
Population Characteristics
• Dispersal Patterns
• Clumped
Population Characteristics
• Dispersal Patterns
• Uniform
Population Characteristics
• Dispersal Patterns
• Random (ferns)
Population Characteristics
• Demographics
• Study of vital statistics
• Age structure
– Groupings by age
– Graphed
• Sex ratio
– % of females
compared to males
Analyze the following graphs
• Determine what is causing the
various demographic trends in
each country
Population Characteristics
Survivorship Curves
• Graph of # of survivors vs. relative age
Survivorship Curves
• Type I
• Most
survive to
middle
age
• Humans
Survivorship Curves
• Type II
• Likelihood
of death
same at
any age
• Squirrel
Survivorship Curves
• Type III
• Most die
young
• Oyster
Limiting Factors – add to notes
at bottom of page 2
• Prevent population from reaching
biotic potential
• Types
– Density dependent
– Density independent
Limiting Factors
• Density dependent
• Effect becomes more intense with
increased density
• Examples
–
–
–
–
Parasites & diseases
Competition for resources
Toxic effect of waste products
Predation
Limiting Factors
• Density independent
• Occur independently of density
• Examples:
– Natural disasters
– Climate extremes
Population Growth Models
• Exponential Growth
• Change in # of individuals (N) over
time (t) is equal to the growth rate (r)
times the number of individuals (N)
N
 rN
t
Population Growth Models
• Exponential Growth
• J-shaped curve
Population Growth Models
• Logistic Growth
• When limiting factors restrict size of
population to carrying capacity
• Carrying capacity (K) = max. # of
individuals of a population that can be
sustained by the habitat
N
KN
 rN 

t
 K 
Population Growth Models
• Logistic Growth
• Sigmoid (S) shaped curve
Life-History Strategies
•
•
•
•
r-selected species
Exhibit rapid growth (J-curve)
Examples – grasses, insects
Characterized by opportunistic species
– Quickly invade habitat
– Quickly reproduce
– Then die
• Produce many offspring that are small, mature
quickly, require little parental care
Life-History Strategies
• k-selected species
• Population size remains relatively
constant
• Example - humans
• Produce small number of relatively
large offspring that require extensive
parental care
• Reproduction occurs repeatedly during
lifetime
Community Ecology
• Defintion
– An assemblage of populations
interacting with one another within
the same environment
– Use the following slides as reference
for question 2
Community Interactions
• Interspecific Competition
• Competition between different species
• When 2 species compete for same
resources one will be more successful
• To survive, the less successful species
– Must use slightly different resources
– Must use resources during different
time of day
Community Interactions
• Predation
• Any animal that totally or partly
consumes a plant or animal
• True predator kills and eats another
animal
• Parasite lives in and off a host
• Herbivore is an animal that eats plants
Community Interactions
• Symbiosis
• Two species that live together in close
contact
• Types
– Mutualism
– Commensalism
– Parasitism
Community Interactions
• Mutualism
• Both species benefit from relationship
• Examples
– Bacteria in root nodules
– Lichens – algae & fungus living
together
Community Interactions
• Commensalism
• One species benefits
while the other is
neither harmed nor
helped
• Examples
– Birds building nests in
trees
– Egrets that eat
insects around cattle
Community Interactions
• Parasitism
• One species benefits while the other is
harmed
• Examples
– Tapeworm inside animal
– Ticks on dog
Ecological Succession
• Def- species replacements in a
community following a
disturbance
• Primary – occurs in areas where
there is no soil formation (volcanic
eruption, glacial retreat)
• Secondary – area where soil is
present (after a fire, farmland)
• Detroit
Climax Community
• F.E. Clements – succession in a
particular area will always yield the
same type of community – this
community is called the Climax
Community
Pioneer species – the first species to
begin secondary succession (plants)
Trophic Levels
• Primary producers
• Plants
• Photosynthetic
bacteria
• Algae
Trophic Levels
• Primary consumers
• Herbivores
• Eat producers
Trophic Levels
• Secondary
consumers
• Carnivores
• Eat primary
consumers
(herbivores)
Trophic Levels
• Tertiary consumers
• Secondary
carnivores
• Eat secondary
consumers
Pyramids
• Pyramid of
numbers
• Most = producers
• Least = top level
consumers
Pyramids
• Pyramid of energy
• Most = producers
• Least = top level consumers
Pyramids
• 10% rule
• Only 10% of
energy
available at
each trophic
level is
converted
into new
biomass at
the next level
Food Chain
Food Web
Nitrogen Cycle
Water Cycle
Carbon Cycle
Human Impact
• Greenhouse effect
• Ozone depletion
• Acid rain
• Deforestation
• Pollution
• Species extinction
Chapter 48
Ecosystems & Human
Interferences
Outline
• The Nature of Ecosystems
– Biotic Components
– Autotrophs
– Heterotrophs
• Energy Flow
– Ecological Pyramids
• Global Biogeochemical Cycles
64
– Hydrologic Cycle
– Carbon Cycle
– Nitrogen Cycle
Nature of Ecosystems
• Biosphere is the organism-containing
part of the
– Atmosphere
– Hydrosphere, and
– Lithosphere
• An ecosystem is a place where
organisms interact with the physical
environment
– Ecosystems characterized by:
• Cyclical flow of materials from abiotic
environment through biotic community
and back
• One-way flow of energy
65
Ecosyste
ms
66
Biotic Components:
Autotrophs
• Producers are autotrophs
– Require only inorganic nutrients and
an outside energy source to produce
organic nutrients
– Photoautotrophs
– Chemoautrophs
67
Biotic Components:
Heterotrophs
• Consumers are heterotrophs
• Require a source of preformed organic
nutrients
– Herbivores - Feed on plants
– Carnivores - Feed on other animals
– Omnivores - Feed on plants and animals
• Decomposers are also heterotrophs
68
Biotic
Components
69
Energy Flow and
Chemical Cycling
• Nutrients pass one-way through food
chain from one level to another
– Each level retains some energy
– The rest is converted to heat, which
dissipates into the environment
• Chemicals cycle as organic nutrients
• Once used, they are returned back to
the producers by
70
– Excretion
Nature of an
Ecosystem
71
Energy
Balances
72
Grazing & Detrital
Food Webs
73
Ecological Pyramids
• A trophic level
• Composed of all the organisms
that feed at the same level in a
food chain
• Only about 10% of the energy of
one trophic level is useable to the
next trophic level
– Explains why few top carnivores can
be supported in a food web
74
Ecological
Pyramid
75
Global
Biogeochemical Cycles
• Chemical cycling may involve:
– Reservoir - Source normally
unavailable to producers
• Fossil Fuels
• Minerals
• Sediments
– Exchange Pool - Source from which
organisms generally take chemicals
• Atmosphere
• Soil
• Water
76
– Biotic Community - Chemicals remain
Model for Chemical
Cycling
77
Hydrologic Cycle
• Fresh water evaporates from
bodies of water
• Precipitation on land enters the
ground, surface waters, or aquifers
• Water eventually returns to the
oceans
78
The Hydrologic
(Water) Cycle
79
Carbon Cycle
• Atmosphere is an exchange pool
for carbon dioxide
– The total amount of carbon dioxide in
the atmosphere has been increasing
every year
– Thought to be due to fossil fuel
combustion
• Transfer Rate
80
The Carbon
Cycle
81
Greenhouse Effect
• Greenhouse gases
– Carbon dioxide, nitrous oxide, methane
– Allow sunlight to pass through
atmosphere
– Reflect infrared back to earth
– Trap heat in atmosphere
• If Earth’s temperature rises
– More water will evaporate
– More clouds will form, and
– Setting up a potential positive feedback
loop
82
Earth’s Radiation
Balances
83
Nitrogen Cycle
• Atmospheric nitrogen is fixed by
bacteria
– Make it available to plants
– Nodules on legume roots
• Nitrification - Production of nitrates
• Denitrification - Conversion of
nitrate to nitrous oxide and
nitrogen gas
– Balances nitrogen fixation
84
The Nitrogen
Cycle
85
Nitrogen and Air Pollution
• Acid Deposition
– Nitrogen oxides and sulfur dioxide are
converted to acids when they
combine with water vapor
– Acid rain dramatically reduces pH of
surface waters in some areas
– Causes heavy metals to leach out of
rocks, poisoning aquatic organisms
– Kills plants and causes fish to be unfit
for human consumption
• Smog
86
Acid
Deposition
87
Thermal
Inversion
88
Phosphorus Cycle
• Phosphorus does not enter the
atmosphere
– Sedimentary cycle
• Phosphate taken up by producers
incorporated into a variety of organic
molecules
– Can lead to water eutrophication
• Biomagnification
89
The Phosphorus
Cycle
90
Sources of Water
Pollution
91
Review
• The Nature of Ecosystems
– Biotic Components
– Autotrophs
– Heterotrophs
• Energy Flow
– Ecological Pyramids
• Global Biogeochemical Cycles
92
– Hydrologic Cycle
– Carbon Cycle
– Nitrogen Cycle
Ending Slide Chapter 48
Ecosystems & Human
Interferences