Download UNIT 6 PART 1 ORGANIZATION IN THE BIOSPHERE

UNIT 6 PART 1: ORGANIZATION
IN THE BIOSPHERE
• The biosphere is
the part of earth
where living things
exist.
• It is about 20 km
thick from the
ocean floor through
part of the
atmosphere.
• Includes land, sea,
and air.
1
Ecology
The branch of biology
that deals with the
interactions among
living things and their
environment.
ENVIRONMENT
LIVING
THINGS
2
Biotic Factors
• All living things in the environment and
their effects on each other
Eats fish
• Bird
Uses grass for nest
• Fish
Eats insects
Eaten by bird, man
• Man
Eats fish
Mows grass
• Trees Provide shade
Drop leaves
• Plants
Provide food
and oxygen
• Insects Eaten by fish
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Abiotic Factors
• Nonliving things in the environment that
determine what types of organisms can
survive there
AMOUNT
OF LIGHT
AMOUNT OF
WATER
TEMPERATURE
TYPE OF
SOIL
4
Organization of Living Things
• Population- all the
individuals of one
species in an area
• Community- all the
populations in an area
• Ecosystem- the
community and the
environment: all living
(biotic) and nonliving
(abiotic) things
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• Variety in a biological
community is called
biodiversity.
• The greater the
biodiversity, the
more stable the
ecosystem.
– A rain forest has
high biodiversity
– A tundra has low
biodiversity
• Loss of biodiversity
may cause the
ecosystem to
collapse.
Biodiversity
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Limiting Factors and Adaptations
• Some things can limit
the growth of a
population:
–
–
–
–
–
–
Food
Water
Disease
Light
Competition
Predation
• Because of variations,
some individuals will be
better adapted to
survive and reproduce
than others.
• These are called
limiting factors.
7
Carrying Capacity
• When conditions are
good populations
increase.
• Limiting factors control the size of a
population causing growth to slow or reach
equilibrium (birth rate = death rate).
• The maximum population size that an
ecosystem can support (zero growth) is
called the carrying capacity.
8
Types of Organisms
• Autotrophs
(Producers) make
their own food by
photosynthesis or
chemosynthesis.
• Green plants and
some bacteria
• Heterotrophs
(Consumers) eat other
organisms.
• Herbivores eat plants.
• Carnivores eat animals.
– Predators
– Scavengers
• Omnivores eat both.
• Decomposers eat
remains of dead
organisms.
– Fungi
– Bacteria
9
Habitat and Niche
• Each organism has a
particular part of the
environment where it
lives- its habitat.
– Squirrel – tree
– Fox – den
– Rabbit - hole
• An organism’s role in
the ecosystem (its
‘job’) is its niche.
• This includes how,
where, when it feeds,
reproduces, what it
eats, where it lives.
• Habitat is part of
niche.
• Each species has its
own niche.
10
Competition
• Competition occurs when niches overlap.
– Eating the same food
– Reproducing at the same time
• Interspecific competition occurs between
members of different species.
– Squirrels and chipmunks both eat pine seeds.
• Intraspecific competition occurs between
members of the same species.
– Choosing mates
11
ENERGY AND NUTRIENTS IN AN
ECOSYSTEM
• Energy does not cycle through an ecosystem
but must be constantly supplied because it
gets used by organisms. Much of it is lost as
heat.
• Energy comes from the sun and is made
available to all organisms by the producers.
• Other materials, like carbon, nitrogen,
oxygen, and water, do cycle between living
things and their environment.
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NUTRIENT
CYCLES
N
i
t
r
o
g
e
n
Carbon
Water
13
Food Chain
• Within an ecosystem there is a pathway of
energy flow that always begins with the
producers.
Producers  herbivores  carnivores  30
(primary, 10) (secondary, 20)
14
Food Web
• Many interconnected food chains make up
a food web.
15
Pyramid of Energy and Biomass
• In a food chain the
amount of available
energy decreases
with each higher
feeding level.
• Only 10% of the
energy in one level is
passed to the next.
• Since the total
amount of energy
decreases, the
biomass at each level
must also decrease.16
Decomposers – organisms of decay
• Break down the wastes and remains of
dead plants and animals. This changes
organic matter into inorganic matter
that can be reused by other organisms at
all levels.
• The final consumers in
every food chain:
– Fungi
– Bacteria
• They are nature’s
recyclers.
17
Symbiosis is a close relationship between
two or more different organisms that live
together where at least one benefits from the
relationship.
Mutualism
+,+
Parasitism
+,-
Commensalism
+,0
Symbiote
benefits
Symbiote
benefits
Symbiote
benefits
Host benefits
Host harmed
Host unaffected
Bees & Flowers
Leach & Fish
Robin & Tree
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Mutualism
• Both organisms benefit from the relationship:
– Termites and cellulose-digesting microorganisms
– Bees and flowers
– Lichens are an alga and a fungus
– Legumes and nitrogen-fixing bacteria
19
Commensalism
• One organism benefits and the other is
unaffected:
– Barnacles on whales
– Pilot fish and sharks
– Cattle egrets and cattle
20
Parasitism
• One organism benefits and the other is
harmed:
– Tapeworms
– Lampreys
– Mistletoe
21
Ecological Succession
• Ecosystems appear stable but they do undergo
change.
• The living things alter the environment so
species change over time: the community is
replaced.
• One community changes to another until a
stable climax community is reached. This is
ecological succession.
• The climax community stays until there is a
catastrophe such as flood or fire. Then
succession will begin again.
• The different biomes are defined by the climax
community.
22
Ecological Succession on Land
• Primary succession occurs in an area that
has no existing life, such as on a bare rock or
hardened lava.
• Secondary succession occurs in an area
that has been partially destroyed like a
cleared forest.
• The first organisms to inhabit a community are
called pioneers, such as bacteria, fungi and
lichens.
• Pioneers break down the rock and create soil
and humus.
23
Ecological Succession on Land
• Eventually grasses and small animals move
into the area as the soil improves.
• When these die, the soil becomes richer and
can support a greater variety of organisms.
• The grasses are replaced by small shrubs.
• Shrubs are replaced by the taller pines.
• After many years the pines may be replaced by
oaks, beeches or maples. These are the
dominant species that characterize a climax
community.
24
Ecological Succession on Land
25
Ecological Succession in Water
• Small ponds and lakes undergo succession
and gradually fill in.
• Sediments such as soil and leaves wash into
the pond, slowly filling it in from the edges.
• Emergent plants such as cattails and
grasses grow around the edges as the pond
gets shallower.
• Shrubs move into the newly formed soil.
• Trees replace the shrubs as the pond
shrinks.
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Ecological Succession in Water
Chap 25
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