Download Chapter 3 - Kenton County Schools

3.1 – What is Ecology?
Interactions and Interdependence
• Ecology – the study of interactions among organisms and
their environment
• Oikos (ec) – Greek word meaning house
• Ology – means study of
Levels of Organization
•
The levels of organization that ecologists study include:
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Individuals
•
Species – group of similar organisms that can breed
and produce fertile offspring
•
Populations – group of individuals of the same
species that live in the same area and interbreed
•
Communities – several populations that live together
in an area
•
Ecosystem – The interaction of all the organisms and
the environment in a given area
•
Biome – a group of ecosystems that have the same
climate
•
Biosphere – part of Earth in which life exists including
land, water and atmosphere
•
It extends about 8km above the Earth’s surface to
about 11km below
•
If you could shrink earth to the size of an apple, the
biosphere would be thinner than the apple’s peel
Biotic and Abiotic Factors
•
Biotic Factors – all the living organisms in an ecosystem
•
•
Example: tree, bird, bacteria, fungi
Abiotic Factors – nonliving factors in an ecosystems
•
Example: temperature, precipitation, wind, soil, sunlight,
humidity
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Habitat – area where an organism lives including biotic and
abiotic factors
•
Niche – the role and position a species has in its
environment
•
No two species can share the same niche in the same
habitat
3.2 – Energy Flow
•
Sunlight is the main energy source for life
•
Autotrophs
•
Make their own energy
•
Convert sun energy into chemical energy
•
Also called a producer
•
Plants are the main autotrophs on land
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Algae are the main autotrophs in water
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Some autotrophs can produce food in the absence of light
•
Chemoautotrophs – organisms use chemical energy to
produce carbohydrates
•
Live in…
•
Volcanic vents
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Deep ocean
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Hot springs
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Marshes
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Heterotrophs
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Get energy from other organisms
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Unable to make its own energy
•
Also called consumers
•
Types of Heterotrophs
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Herbivores
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Eats only plants
•
Example: cows, deer, rabbits, bees,
elephants, squirrels
•
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Carnivores
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Eats only animals
•
Example: snakes, dogs, lions, crocodiles
Omnivores
•
Eats plants and animals
•
Example: humans, bears, crows
•
•
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Detrivores
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Eat decomposing bits of organic matter
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Example: mites, earthworms, snails, crabs
Decomposers
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Break down organic matter
•
Example: bacteria and fungi
Scavenger
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Ingest nonliving plants and animals
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Example: vulture, termite, beetle
Feeding Relationships
•
Food Chain – a straight line series of steps by which
energy is stored and passed on to higher trophic levels
•
Food Web – a network of crossing interlinked food chains
that shows all the possible feeding relationships at each
trophic level
•
Trophic Levels – the different feeding relationships in an
ecosystem.
•
Plants and other producers are 1st trophic level
•
Consumers make up the 2nd, 3rd, or higher trophic
levels
•
Each consumer depends on the trophic level below it
for energy
•
Energy is transferred from one trophic level to another
and is never 100%
•
At each trophic level only 10% of the energy taken in
by the organism is stored.
•
Energy is passed through no more than four or five
trophic levels
Ecological Pyramids
•
Ecological Pyramid – a diagram that shows the relative
amounts of energy or matter contained within each
trophic level in a food chain or food web
3-3 Cycles of Matter
Properties of Water
•
Water is perhaps the most important compound in living
organisms
•
Water serves as a means of material transportation in
organisms.
•
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Hydrogen bond – attraction between opposite charged
molecules (H+ O-)
•
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Ex. Blood (is mostly water)
Are important because they help hold many large
molecules such as proteins together.
Water resists changes in temperature
•
Water requires more heat to increase its temperature.
•
Water is like an insulator
•
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Water is one of the few substances that expands when it
freezes.
•
•
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maintains homeostasis
Ice is less dense than liquid
Cohesion – attraction between like molecules
•
Cohesion creates tension
•
Tension – inward pulling on water molecules at the
surface
Adhesion – attraction between different molecules
•
Biogeochemical Cycles – chemicals and nutrients are
transferred from environment into organisms then back
to the environment
The Water Cycle
•
Evaporation – process by which water changes from a
liquid to a gas
•
Transpiration – loss of water from plants by the process
of evaporation
•
How does water move up a plant?
•
Xylem – tubes in plants that transport water from
roots to leaves.
•
On sunny days, water evaporates from leaves
•
Adhesion & Cohesion pulls up more water
molecules into leaf cells
•
Condensation – water vapor changes to a liquid
•
Precipitation – water returns to the earth (rain, snow,
hail)
Click to view
animation.
3
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4
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5
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5
CO2
2
1
Burning Fossil Fuels
Volcanic
Activity
3
Burning Trees
Photosynthesis
4
Respiration
7
Organism eats plants
C6H12O6
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11
Oil
10
Decomposition
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Coal
Root Uptake
Gaseous Nitrogen
N2
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6
2
Nitrogen Fixation
Ammonification
Denitrification
Bacteria in the soil convert
Bacteria convert wastes and
decomposing organics to
Bacteria convert
N2 → NH3 → NH4
NO3 → N2
NH3 → NH4
5
Autotrophs can take up
NH4 and NO3
3
4
Nitrification
Bacteria convert
NH4 → NO2 → NO3
•
Humans are harming the nitrogen cycle by:
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Deforestation
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Conversion of grasslands for agriculture
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Sewage enters waterways
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Fossil fuel burning
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Vehicles having combustion engines releases NO2