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Biology
Ecology
Chapters 2-5
Ecology
Topics
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Essential Questions
1.
What is ecology? What do ecologists study?
Introduction to
Ecology
2.
Compare and contrast biotic and abiotic factors.
What is their importance in an ecosystem?
Abiotic & Biotic
factors of an
Ecosystem
3.
Identify and describe the following symbiotic
relationships: mutualism, commensalisms, and
parasitism.
4.
Describe the relationship of a predator to its
prey.
Predator/ Prey
Relationships
Symbiotic
Relationships
Ecology – Key Terms
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Ecology
Abiotic
Biotic
Population
Community
Ecosystem
Habitat
Niche
Predator
Prey
Symbiosis
Commensalism
Parasitism
Mutualism
Organism
Biosphere
Organizing key terms:
Organization
Living v. nonliving
Relationships
Biosphere
Biotic (living)
Symbiosis:
Mutualism (+/+)
Commensalism
(+/0)
Parasitism (+/-)
Abiotic (nonliving)
Ecosystem
Community
Predator
Prey
Population
Organism
(species)
Habitat
(location)
Niche
(role / job)
What is Ecology?
Ecology is the study of the interactions of living organisms with one
another and with their nonliving environment of matter and energy; study of
the structure and functions of nature
What roles do insects
play?
Ecosystem Organization Overview
Biosphere- Zone of earth where life is found.
Sometimes called the ecosphere
Ecosystems- Community of different species
interacting with one another and with the chemical
and physical factors making up its nonliving
environment
Communities- Populations of all species living and
interacting in an area at a particular time
Populations- Group of individual organisms of the
same species living in a particular area
Organisms Any form of life (species)- group of
organisms that resemble one another in
appearance, behavior, chemical makeup and
processes, and genetic structure.
What are the Characteristics of Life?
Biotic – living components of an ecosystem
Abiotic – Nonliving component of an ecosystem
All things living have the following
specific properties:
Known species
1,412,000
Other animals
281,000
Cellular organization
Metabolism
Homeostasis
Reproduction
Fungi
69,000
Insects
751,000
Prokaryotes
4,800
Heredity
About 1.4 million species have
been identified, but estimates
of number of species range
from 3.6 million to 100 million
Plants
248,400
Protists
57,700
Ecosystem
Components
The major components of
ecosystems are abiotic
(nonliving) water, air,
nutrients, solar energy, and
biotic (living) plants,
animals, and microbes.
Niche – How organisms
interact with each other
within a community. An
organism role in the
ecosystem
Habitat is the place
where a population or an
individual organism
usually lives
Major Biomes and the Role of Climate
The amount of energy
received and
topography of a region
determines climate.
Terrestrial parts of the
biosphere are classified
as biomes, areas such
as deserts, forests, and
grasslands.
Temperature, precipitation and topography
(abiotic factors) determine the vegetation (plants)
and the animals they will support
Aquatic life zones
describe the many
different areas found in
a water environment,
such as freshwater or
marine life zones (coral
reefs, coastal estuaries,
deep ocean).
Biomes of the World
Polar
Temperate
Tropic of
Cancer
Equator
Tropics
Tropic of
Capricorn
Arctic tundra (polar grasslands)
Desert
Boreal forest (taiga), evergreen coniferous
forest (e.g., montane coniferous forest)
Tropical rain forest,
tropical evergreen forest
Semidesert,
arid grassland
Mountains
(complex zonation)
Temperate deciduous forest
Tropical deciduous forest
Ice
Temperate grassland
Tropical scrub forest
Dry woodlands and
shrublands (chaparral)
Tropical savanna,
thorn forest
Tropical Rainforest
Deserts
Deciduous Forest
Tundra
Grassland
Taiga
Aquatic Life Zones-Marine and freshwater portions of the biosphere. Examples include
freshwater life zones (such as lakes and streams) and ocean or marine life zones
Sun
Sea level
0
50
Euphotic Zone
100
Estuarine
Zone
Continental
shelf
Photosynthesis
Open Sea
Depth in
meters
200
500
Bathyal Zone
1,000
Twilight
High tide
Low tide
Coastal Zone
1,500
2,000
3,000
Marine Life Zones
4,000
5,000
10,000
Darkness
Abyssal Zone
Relationships
Symbiotic Species Interactions:
Mutualism (+/+)
Pollination mutualism
Insects
Nutritional mutualism
Hermit crabs and Anemones
Monkeys and Deer
Gut inhabitant mutualism
Cellulose digesting protozoa
Parasitism (+/-)
Parasite – organisms feeding on or in
another species
Host – organisms fed on by parasites
External parasites
Internal parasites
Commensalism (+/0)
Species interaction that benefits
one and has little or no effect on
the other.
Example: Small plants growing
in shade of larger plants or
Hermit crab and Rag worm
Lifecycle of a Parasite
Symbiosis Overview
The head of the
tapeworm is called a
scolex, and is equipped
with hooks and suckers
which are used for
attaching to the intestinal
wall of the host. Adult
tapeworms, some
reaching a length of 15
feet, are parasites in the
guts of animals and
absorb nutrients across
their body surface. The
structures behind the
head are called
proglottids.
Species Interactions – Predation / prey
Prey Acquisition
Example: Killer Whales
Predator Avoidance
Camouflage
Span worm
Deceptive
Behavior
Wandering leaf insect
When touched, the
snake caterpillar
changes shape to look
like the head of a snake
Deceptive
Look
Chemical
Warfare
Hind wings of Io moth
resemble eyes of a
much larger animal
Poison dart frog
Mimicry
Bombardier beetle
Foul-tasting monarch
Butterfly
Viceroy butterfly
mimicsmonarch butterfly
Ecology
Topics
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Essential Questions
5.
Explain the ways in which energy flows through
an ecosystem.
6.
What role does the carbon cycle play in
photosynthesis and cellular respiration?
7.
How are communities influenced? What are the
major limiting factors that influence carrying
capacity?
8.
What do population growth graphs look like?
Can you identify them?
Ecosystem
energy flow
Cycles in an
ecosystem
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Limiting Factors
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Population
Growth Graphs
Ecology – Key Terms
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Autotrophs / Producer
Photosynthesis
Heterotrophs / Consumer
Cellular Respiration
Decomposer / Consumer
Food Chain
Food Web
Energy Pyramid
Biomass
Limiting Factor
Biotic Potential
Environmental Resistance
Carrying Capacity
Logistic Growth
Exponential Growth
Natural Capital: Sustaining Life of Earth Flow of Energy to and
from the Earth
From the sun to the Earth
Remote Sensing
One-way flow of energy from Sun
Cycling of Crucial Elements
Gravity
Ecosystem Components
Glucose and other organic compounds are broken down and energy
released by the process of aerobic respiration, the use of oxygen to
convert organic matter back to carbon dioxide and water. This process
is a net chemical change to that of photosynthesis.
Photosynthesis: CO2 + H2O
Carbon
dioxide
water
CO2 + H2O
Light
C6H12O6 + O2
Glucose
sugar
oxygen
C6H12O6 + O2 Aerobic Respiration
“Cellular Respiration”
Some decomposers are able to break down organic compounds without
using oxygen. This process is called anaerobic respiration, or
fermentation. The end products are compounds such as methane gas,
ethyl alcohol, acetic acid, and hydrogen sulfide.
Matter is recycled; there is a one-way
flow of energy.
Food Chains and Energy Flow in Ecosystems
Food chains and food webs
help us understand how
eaters, the eaten, and the
decomposed are
interconnected in an
ecosystem.
The sequence of organisms as
they are eaten is a food chain.
Food webs are complex
networks of interconnected
food chains. They are maps of
life's interdependence.
Trophic levels are feeding levels for organisms within an ecosystem,(1) Producers
belong to the first trophic level. (2) Primary consumers belong to the second trophic
level.(3)Secondary consumers belong to the (4) third trophic level.Detritivores and
decomposers process detritus from all trophic levels.
Energy flow in a food web/chain decreases at each succeeding organism in a chain or
web. The dry weight of all organic matter within the organisms of a food chain/web is
called biomass.
Tropic Levels
Humans
Blue whale
Ecological efficiency is the
term that describes the
percentage of usable energy
transferred as biomass from
one trophic level to another
and ranges from 2%-40%
with 10% being typical.
Sperm whale
Killer
whale
Elephant
seal
Crabeater seal
Leopard
seal
The greater number of
trophic levels in a food chain,
the greater loss of usable
energy.
Emperor
penguin
Adélie
penguins
Petrel
Squid
Fish
Carnivorous plankton
Herbivorous
zooplankton
Krill
Phytoplankton
Ecological Pyramids
Pyramid of energy flow
The pyramid of energy flow
visualizes the loss of usable
energy through a food
chain. The lower levels of
the trophic pyramid support
more organisms. If people
eat at a lower trophic level
(fruits, vegetables, grains
directly consumed), Earth
can support more people.
There is a large loss of
energy between successive
trophic levels.
Pyramid of biomass
Compares biomass (The dry
weight of all organic matter
within the organisms of a
food chain/web) at each
trophic level
Pyramid of numbers
Compares the total number of organism at each
trophic level
Ecosystem Factors
Ecosystem characteristics include a range of
tolerance to physical and chemical
environments by the ecosystem's
populations Law of tolerance: The
distribution of a species in an ecosystem is
determined by the levels of one or more
physical or chemical factors being within the
range tolerated by that species.
Aquatic life zones can be limited by the
dissolved oxygen (DO) content in the water,
temperature, pH or by the salinity
Sugar Maple
The limiting factor principle
states that too much or too
little of any abiotic factor can
limit or prevent growth of a
population, even if all other
factors are at or near the
optimum range of tolerance.
An abiotic factor such as lack
of water or poor soil can be
understood here
The Study of Population Dynamics
Populations change in size, density, dispersion and age structure.
Population density —the number of individuals of a population that
inhabit a certain unit of land or water area.
Population dispersion —refers to how individuals of a population are
spaced within a region.
Age structure of a population is usually described as the
pre-reproductive stage, the reproductive stage and the postreproductive stage. A population with a large reproductive stage is
likely to increase, while a population with a large post-reproductive
stage is likely to decrease.
Population Size
Four variables influence/govern
population size: (1) births, (2)
deaths, (3) immigration, and (4)
emigration.
Increase in population occurs by birth
and immigration.
Decrease in population occurs by death
and emigration.
Rapidly growing populations have four
characteristics:
1. Individuals in the population reproduce early in
life.
2. Individuals have short periods between
generations.
3. Individuals have long reproductive lives.
4. Individuals produce multiple offspring each time
they reproduce.
Biotic Potential vs.
Environmental Resistance
The biotic potential max (rmax) is the population's
capacity for growth. The intrinsic rate of increase
(r) is the rate of population growth with unlimited
resources.
environmental resistance
consists of factors that limit population growth.
limiting Factors
No population can grow
indefinitely due to
limited resources such
as light, water, and
nutrients and also due
to competitors and/or
predators.
Limiting Factors Examples:
Extrinsic
Biotic – Density Dependent
Abiotic – Density Independent
Intrinsic
Social Hierarchy
Gender changing
Density-independent population
controls affect a population's size
regardless of its density. These are
abiotic factors in the community.
Density-dependent factors or
population controls have a greater
affect on the population as its
density increases. Infectious
disease is an example of densitydependent population control.
Biotic Potential v. Environmental Resistance
(Logistic Population Growth)
Environmental
resistance
Population size (N)
Carrying capacity (K)
Carrying capacity (K)
is determined by biotic
potential and environmental
resistance.
(K) is is the number of a
species individuals that can
be sustained indefinitely in a
specific space.
Biotic
potential
Exponential
growth
Time (t)
As a population reaches its
carrying capacity, its
growth rate will decrease
because resources
become more scarce.
The Role of Predation in Controlling Population Size
Interactions between
predators and their prey
change in cycles and appear
to be caused by species
interactions, but other factors
may be involved.
The hypothesis of top-down
control of prey by predators
may not be the only
explanation for the boomand-bust cycles seen in these
populations. This may also be
related to the food supply of
prey.
The bottom-up control
hypothesis states that plants
are consumed too rapidly by
prey for replacement to keep
up. This may lead to a crash
of herbivores, and that may
lead to a crash of higher
predators.
Fig. 9-8 p. 168
These are not mutually exclusive
hypotheses; more probably have
interaction between predation and
food supplies.
Ecology
Topics
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Human
population growth
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Biodiversity
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Impacts on the
environment
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Factors
influencing
climate
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Direct & Indirect
influence on
natural resources
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Conservation
Essential Questions
9. What factors affect the growth of human
populations?
10. What is biodiversity? Describe the importance
of it.
11. How do both the changes and the needs of a
human populations impact the environment?
12. What are the factors that influence climate?
13. How do humans directly and indirect influence
natural resources? What some practices that
can be done to improve and conserve the
natural world?
World Population and Exponential Growth
“Rule of 70”
Doubling Time
As the human
population
grows what
might be the
impact on
(1) resources use
and waste
(2) poverty
(3) loss of
biodiversity
(4) Global Climate
Change
2008
Living on interest vs. Living on principal
Living on Interest (Sustainably)
Imagine you win $1,000,000 in
the lottery
Invest the capital (1 million) at
10% interest.
You will have a sustainable
income of $100,000 per year.
Without depleting your capital
(1 million)
Living on Principal
If you spent $200,000 per year,
your 1million would be gone
early in the 7th year
If you spent $110,000 per year,
you would be bankrupt early in
the 18th year.
How would you prefer to live?
How do we live now?
Who is Overpopulated?
Population Growth
Are we living
Sustainably?
Is the problem we face
population size or resource
use?
Fig. 1-4, p. 8
return
Ecological Footprint
What is an ecological footprint?
Age of Consumption – Examples of over consumption
How have human activities affected the Earth’s biodiversity?
Humans have disturbed from 50 to 83% of the earth's land surface.
Humans use, waste, or destroy about 40% of the net primary productivity of the
planet's terrestrial ecosystems.
Planet in Peril – Battle lines (2009)
Examples / Issues:
Bush Meat / Zoonotic Viruses
Nigerian Oil Conflict
Peruvian Lead poisoning
Shark fining and Ecotourism
African Elephants
Mountain Gorillas
Planet in Peril (2007)
Thailand Species Trade
China and Cambodia
Why should we care about
biodiversity?
Preservation of biodiversity is important for
several reasons, such as intrinsic or
existence value, and also because of its
usefulness to humans (Instrumental
Value)
Instrumental value consists of use values that
benefit people for goods and services,
scientific information, recreation, and
ecological services.
Nonuse values are
(1) existence value,
(2) aesthetic value (the appreciation of wild
species, or a view for beauty alone), and
(3) bequest value (the act of leaving natural
capital for use by future generations).
What is Conservation Biology?
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Conservation biology is a multidisciplinary
science that originated in the 1970’s. Its
goal is to use emergency responses slow
down the rate destruction and degradation
Goals, strategies, and tactics for protecting
biodiversity
Climate Change and
Human Activities
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Increased use
of fossil fuels
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Global
warming
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Melting icecaps
and glaciers
Planet in Peril –
Sea Level Rise
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Rising sea level
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Deforestation
Factors Affecting the Earth’s Temperature
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Changes in solar output
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Changes in Earth’s albedo
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Moderating effect of oceans
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Clouds and water vapor
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Air pollution
Greenhouse effect
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Greenhouse gases
Loss of the Ozone Layer: Reasons
for Concern
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Increased incidence and
severity of sunburn
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Increase in eye cataracts
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Increased incidence of skin cancer
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Immune system suppression
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Increase in acid deposition
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Lower crop yields and
decline in productivity
Seasonal Ozone Layer
Thinning at the Poles
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Ozone thinning (hole)
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Polar vortex
Skin
Cancer
Endangered
planet 1990
State of the
Planet 2007
The Lorax