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Chapter 3: The Biosphere
What is ecology?
Ecology
•
–study of interactions
among organisms,
between organisms, and their environment
•
–
Life depends on other living things and natural
resources (air, water, land)
Levels of Organization
1. Species
living thing
Levels of Organization
2. Population
•
of
of individuals
species in an area.
Levels of Organization
•
3. Community
that live together in an area.
• Several populations interacting together.
Levels of Organization
4. Ecosystem
• Collection of all
organisms
(
)
in a particular
place together with
the
(physical)
environment.
Levels of Organization
5. Biomes
•
of
with similar climate and communities.
Levels of Organization
6. Biosphere
• The highest
level of
organization.
• The portion of
the
that supports
life.
Levels of Organization
Biotic and Abiotic Factors
• Biotic –
– Plants, Animals ,Mold, Fungi,
Bacteria, Protist
• Abiotic –
– Sunlight, soil, wind, water,
temperature
Ecological Methods
1.
–
1st step to designing an
experiment
2.
–
test hypotheses
3.
–
make models based on
observation & experiment
• Helps make future predictions
3.1 Review
1. Many populations together is called a…
2. Combination of biotic and abiotic factors in an
environment make up the…
3. What’s the different between biotic and abiotic?
3.2 ENERGY FLOW
(Autotrophs and Heterotrophs)
• One of the most important factors
to determine capacity to sustain life is
Energy Flow
Autotrophs (
)
• Trap light energy to produce food
– Plants
– Some protists
– Some bacteria
•
–
Converts light into chemical energy
6CO2 + 6H2O SUN
•
C6H12O6 + 6O2
–
Converts chemical energy into carbohydrates
Heterotrophs (
• Must acquire energy from
other organisms
– Herbivores –
– Carnivores – animals
–
– both
–
–
eat dead plants & animals
– Decomposers – break down
organic matter
)
3.2 Review
1. Another name for autotroph is…
2. What are the two processes autotrophs use to
make energy?
3. What are the four types of –vores?
3.3 Energy Flow in
Ecosystems
• Food Chains and Food Webs
Food Chains and Food Webs
SUN
Autotrophs
Heterotroph
1. Food
– shows
energy transfer
2. Food
– shows possibilities
of energy transfer
Trophic Levels
• Trophic Levels –
in a food chain/web
T Level 2
T Level 1
Ecological Pyramids
• Ecological Pyramids – shows relative amount of
energy at each level (
)
•
– total amount of living tissue
within a trophic level
3.3 Review
1. Which is more complex – food chain or web?
2. Grass  rabbit  fox  alligator – Which is T2?
3. What is biomass?
4.2 Niches and Community
Interactions
Tolerance
Species ability to survive and reproduce under a
of environmental
.
Intolerance Zone
Habitat
• General place an organism
• Determined by species
.
.
Niche
the
of physical and biological
in which a species lives and
the species
what it
needs to survive and reproduce.
Niches
•
– Things needed for
– Plants- sunlight, water and soil nutrients
– Animals- nesting, space, shelter, food, places to feed
•
resources–
required for survival.
factors
– Ex- amphibians lose and absorb water through skin::must
live in moist places.
•
resources–
factors
required for survival.
– E.g. when/how reproduces, food, way obtains food.
Competition
• Different organisms attempting to use
resources.
•
resources at
time and place =
–
–
specific competition-same species competing
specific competition- different
species competing
What do you think these two
males are fighting over?
Competitive Exclusion Principle
the
two species can occupy exactly
at the same time.
-One species will win
and survive.
-One will lose and die.
Dividing Resources
• Helps determine the
and
of species in a
community and the
niche each species
occupies.
Predation, Herbivory, and Keystone
Species
Predation
Where one animal (the
captures and feeds on
another animal (the
)
)
Predation
• Predators affect
of
population
and determine the places prey can
.
– E.g. birds can play important role in regulating
mouse population sizes
Herbivores
• Herbivory - Animal (herbivore) feeds on
(plants)
• Affect
and
of
.
• E.g- Many white-tailed
deer are eliminating
their favorite
food plants across US.
Keystone Species
• A
species that can
change
in a community
• Ex- Sea otters eat large amounts of sea urchins,
which eat kelp.
• Sea otters almost
by hunting; urchins
population
; ate all the kelp.
• Other organisms also
.
Symbioses
Any relationship in which
species live
together
• Three main classes:
1. Mutualism
2. Parasitism
3. Commensalism
Mutualism
• Relationship in which
species
• E.g. – Sea anemone and clownfish
• Sea anemone-offers shelter; clownfish protects for
preditors.
Parasitism
Relationship where one
organism lives
another organisms and
.
Commensalism
Relationship where
organism
and the
harmed or helped
_
is
4.2 Review
1. What could be a physical and biological resource
for a flower?
2. When does competition occur?
3. Ants protecting a tree that gives the ants shelter
is an example of…
Chapter 5
Populations
5-1
How Populations Grow
How Populations Grow
• Characteristics of Populations
• 4 important characteristics of a
population
–Geographic
–
–Growth
–
structure
Geographic Distribution
–Geographic distribution –
by a population.
–Ranges can vary enormously
in
Population Density
• Population Density - number of
individuals
.
• This picture shows the population density
of people.
Populations Growth
• Three factors affect population size:
– number of
– number of
– number of individuals that
the population.
* Simply put, a population will increase or decrease in size
depending on how many individuals are added to it or
removed from it
Immigration & Emigration
•
–movement of individuals
an area
• causes growth.
•
–movement of individuals
of an area
• causes decrease.
Age Structure
•
of males and females of
a population contains.
• Age structure greatly effects reproduction
Exponential Growth
• Exponential growth – When the
generation is
than the generation
.
• Population size will increase if there is
abundant
and
, and
protected from predators and disease
• Under ideal conditions with unlimited
.
Logistic Growth
• Logistic growth- occurs when growth
following
a period of exponential growth.
• As
,
the growth of a population slows or stops.
• The general, S-shaped curve of this growth
pattern, is called
growth.
Carrying Capacity

number of
individuals of a particular species that a
given environment can
.
1. List the four characteristics of population.
2. What factors can change a population's size?
3. What is carrying capacity?
5.2 Limits to
Growth
•
factor – factor that controls
the
of a population.
– Density dependent
– Density independent
• Limiting factors
the
capacity of an
environment for a species.
Density- Dependent
Factors
• Limit size when the
individuals reach a certain
1.
space, sunlight, etc.
2. Predation and
populations cycle up and down
of
for food, water,
–
Wolf/Moose graph
Moose
Wolves
Density- Dependent Factors
Continued
3.
– the
the
population, the easier it spreads
4.
from overcrowding –
can lower birth rates, higher death rates, can
cause parents to neglect young, lead to
emigration
Density -Independent
Factors
• Affect all populations
and density
• Weather,
,
seasonal change, human interventions (dams,
logging, housing developments)
1. What are the two types of limiting factors?
2. What are the four density-dependent factors?
3. Define density-independent factors.
5.3 - Historical Overview
– For most of human existence, the population
grew slowly because life was harsh. Food was
hard to find. Predators and diseases were
common and life-threatening.
Historical Overview
– Limiting factors kept human death rates
.
Until fairly recently, only
the children
in the world
to adulthood.
– Because death rates were so high,
families had
children, just to make
sure that
would survive.
Exponential Human
Population Growth
– As civilization
life became
population began to
,
, and the human
more rapidly.
• What types of things made life easier?
The Predictions of Malthus
– Exponential growth
continue
– Two centuries ago, English economist Thomas
Malthus suggested that only
,
and disease could limit human population growth.
– Malthus’s work was vitally important to the thinking
of Charles
.
The Demographic Transition
– Three stages
– Stage I, birthrates and death
for most of history.
are
The Demographic Transition
– In Stage II, advances in nutrition, sanitation,
and medicine lead to
.
– Birthrates remain
• Births exceed deaths
• Population
exponentially.
The Demographic Transition
– During Stage III, as
and living
standards
, families have fewer
children; population growth
.
– When the birthrate
death rate,
growth stops.
The Demographic Transition
– So far, the United States, Japan, and Europe have
the demographic transition.
– Parts of South America, Africa, and Asia are passing
through
.
– A large part of ongoing human population growth is
happening in only ten countries, with
in the lead.
1. What are three things Malthus suggested
would decrease population size?
2. Which demographic stage has advances that
result in higher birthrates and lower death
rates?
3. In Stage III, why would families have fewer
children?