Biology – Unit 2
Ecology
• Opening Assignment:
• Explain in your own words what
the term “ecology” means.
Part 1 – Lesson 3.1 What is
Ecology?
Ecology- the study
of how organisms
interact with each
other and with their
environment
Abiotic
Factors
Abiotic factors- the nonliving parts of the environment.
• They include:
• Sunlight
• Water
• Temperature
• Wind
• Soil type
• The atmosphere
• The types and amounts of
abiotic factors that are available
in an ecosystem help determine
which organisms can live there.
Biotic Factors
biotic factors- all the living things or
once-living things in an environment.
• Ex:
•
•
•
•
Animals
Plants
Bacteria
Fungi
Organization In The
Environment
The biosphere
consists of all life on
Earth and all parts of
the Earth in which life
exists, including land,
water, and the
atmosphere.
Biome — a geographic area that contain groups of
ecosystems with similar biotic and abiotic features.
• Terrestrial (land) Biomes include:
• Forests
• Deserts
• Tundra
• Grasslands
• Aquatic Biomes include:
• Marine
• Freshwater (rivers & lakes)
• Estuaries
Ecosystem—all the organisms that live in a place, together
with their physical environment(abiotic factors)
• The types and
amounts of abiotic
factors that are
available in an
ecosystem help
determine which
organisms can live
there
Community—All the populations of species that
live in the same area and interact
Population-a group of
individuals that belong to the
same species and live in the
same area
Organism- any unicellular or multicellular form
exhibiting all of the characteristics of life, an individual
Part 1 – Lesson 3.2
Energy, Producers, and
Consumers
• All Life on Earth needs
energy for cell processes.
• For most life on Earth,
sunlight is the ultimate
energy source.
• Organisms get energy by
using light or chemical
energy to make food or by
eating other organisms
PRODUCERS
• Producers change the energy available in their
environment into food energy.
•
They make their own food (autotrophs)
• Plants, algae, and some microorganisms use a chemical
process called photosynthesis to change light energy
into chemical energy (Glucose)
•
This process adds oxygen to the atmosphere and removes carbon
dioxide.
Producers That Use Sunlight
phytoplankton
Plants &
Trees
Algal colony
cyanobacteria
Life Without Light
• Biologists have discovered thriving
ecosystems around volcanic vents in total
darkness on the deep ocean floor.
• Deep-sea ecosystems depend on primary
producers that harness chemical energy
from inorganic molecules such as
hydrogen sulfide.
• The use of chemical energy to produce
carbohydrates is called chemosynthesis.
giant tube worms
live in symbiosis
with the
chemosynthetic
bacteria
Consumers
• Consumers- organisms that cannot make their own food and
get their energy from eating other organisms. (heterotrophs)
• Producers and Consumers use the chemical process of
Cellular Respiration to break down food in the presence of
oxygen to produce energy.
Types of
Consumers
• Consumers are classified by
the ways in which they
acquire energy and nutrients.
• Herbivores-obtain energy
and nutrients by eating plant
leaves, roots, seeds, or fruits.
Types of Consumers
Carnivores- kill and eat other consumers
Types of Consumers
• Decomposers-such as bacteria
and fungi, feed by chemically
breaking down organic matter.
• The decay caused by
decomposers is part of the
process that produces detritus—
small pieces of dead and decaying
plant and animal remains.
•
Decomposers that live on, and in,
detritus particles are called
Detrivores.
• They feed on detritus particles,
often chewing or grinding them into
smaller pieces. Ex: giant
earthworms
Opening Assignment:
• List the levels of organization of life.
• Explain the difference between biotic and
abiotic factors in ecosystems and give 3
examples of each.
Part 2 – Lesson 3.3
Energy Flow in Ecosystems
• Each time one organism eats another organism, a
transfer of energy occurs
• Food chain- models how energy flows in an
ecosystem through feeding relationships.
Food Webs
Food web- links all of
the food chains in an
ecosystem together.
• It shows many
feeding relationships
that are possible in
an ecosystem
An example of a food web
in the Everglades is shown.
Trophic Levels and Energy Pyramids
• Each step in a food chain
or food web is called a
trophic level.
• Primary producers always
make up the first trophic
level.
• Various consumers
occupy every other level
• Energy pyramids- show
the amount of food energy
available at each trophic
level
Trophic Levels and Energy Pyramids
•
•
Energy pyramidsshow the amount of
food energy available
at each trophic level
• Each time energy is
transferred from one
organism to another,
lost and less energy is
available at the next
trophic level.
Trophic Levels and Energy
Pyramids
• Energy is lost:
 as heat
 through cellular respiration.
o this energy is used to carry out functions of living
things such as producing new cells, regulation of
body temperature, and moving around
Trophic Levels and Energy
Pyramids
• The remaining 10% of the energy becomes part of the
organism’s body and is stored in its molecules.
• This 10% is available to the next trophic level when one
organism consumes another organism
Part 2 – Lesson 3.4 Cycles of
Matter
• Learning Goals: Students will be able to . .
• Identify and describe the flow of nutrients in
each biogeochemical cycle.
• Explain the impact that humans have on the
biogeochemical cycles.
• http://www.youtube.com/watch?v=09_sWPx
QymA
Two Secrets of Survival: Energy
Flow and Matter Recycle
• An ecosystem
survives by a
combination of
energy flow and
matter recycling.
Figure 3-14
MATTER CYCLING IN ECOSYSTEMS
• Nutrient Cycles: Global Recycling
• Global Cycles recycle nutrients through the earth’s
air, land, water, and living organisms.
• Nutrients are the elements and compounds that
organisms need to live, grow, and reproduce.
• Biogeochemical cycles move these substances
through air, water, soil, rock and living organisms.
What Sustains Life on Earth?
• Solar energy, the
cycling of matter,
and gravity
sustain the
earth’s life.
Figure 3-7
The Water Cycle
Condensation
Rain clouds
Transpiration
Precipitation
to land
Transpiration from
plants
Precipitation
Runoff
Surface runoff
(rapid)
Evaporation
Evaporation
from land
Precipitation
Evaporation
from ocean
Precipitation
to ocean
Surface
runoff
(rapid)
Infiltration and
Percolation
Groundwater movement (slow)
Ocean storage
Fig. 3-26, p. 72
Effects of Human Activities
on Water Cycle
• We alter the water cycle by:
•
•
•
•
Withdrawing large amounts of freshwater.
Clearing vegetation and eroding soils.
Polluting surface and underground water.
Contributing to climate change.
The Carbon Cycle
1.
2.
3.
4.
Plants remove carbon dioxide from the air.
When the plants died, they were buried in the earth.
After millions of years, their remains turned into coal and oil.
People mine the earth for coal and oil, which are called
"fossil fuels".
5. When people burn fossil fuels, they send carbon dioxide and
other greenhouse gases into the air.
Effects of Human Activities
on Carbon Cycle
• We alter the carbon
cycle by adding
excess CO2 to the
atmosphere through:
• Burning fossil fuels.
• Clearing vegetation
faster than it is
replaced.
Figure 3-28
The Nitrogen Cycle
• This picture shows the flow of the nitrogen cycle. The most important part
of the cycle is bacteria. Bacteria help the nitrogen change between states
so it can be used. When nitrogen is absorbed by the soil, different bacteria
help it to change states so it can be absorbed by plants. Animals then get
their nitrogen from the plants.
Steps in the Nitrogen cycle
1. Fixation - Fixation is the first step in the process of making
nitrogen usable by plants. Here bacteria change nitrogen into
ammonium.
2. Nitrification - this is the process by which ammonium gets
changed into nitrates by bacteria. Nitrates are what the plants
can then absorb.
3. Assimilation - This is how plants get nitrogen. They absorb
nitrates from the soil into their roots. Then the nitrogen gets
used in amino acids, nucleic acids, and chlorophyll.
4. Ammonification - This is part of the decaying process. When a
plant or animal dies, decomposers like fungi and bacteria turn
the nitrogen back in ammonium so it can reenter the nitrogen
cycle.
5. Denitrification - Extra nitrogen in the soil gets put back out into
the air. There are special bacteria that perform this task as
well.
The Phosphorous Cycle
mining
excretion
Fertilizer
Guano
agriculture
uptake by
uptake by weathering
autotrophs
autotrophs
leaching, runoff
Dissolved
Land
Marine
Dissolved
in Soil Water,
Food
Food
in Ocean
Lakes, Rivers
Webs
Webs
Water
death,
death,
decomposition
decomposition
weathering
sedimentation
settling out
uplifting over
geologic time
Rocks
Marine Sediments
Fig. 3-31, p. 77
Steps of the Phosphorous Cycle
• 1. Phosphate is released by the erosion of
rocks.
2. Plants and fungi take up the phosphate with
their roots.
3. Phosphorus moves from producers to
consumers via food chain.
4. Phosphorus may seep into groundwater
from soil, over time forming into rock.
5. When these rocks erode, the cycle begins
again.
Effects of Human Activities
on the Phosphorous Cycle
• We remove large amounts of phosphate from
the earth to make fertilizer.
• We reduce phosphorous in tropical soils by
clearing forests.
• We add excess phosphates to aquatic systems
from runoff of animal wastes and fertilizers.
The Sulfur Cycle
Sulfur
trioxide
Water
Acidic fog and
precipitation
Sulfuric acid
Ammonia
Oxygen
Sulfur dioxide
Ammonium
sulfate
Hydrogen sulfide
Plants
Dimethyl
sulfide
Volcano
Industries
Animals
Ocean
Sulfate salts
Metallic
sulfide
deposits
Decaying matter
Sulfur
Hydrogen sulfide
Fig. 3-32, p. 78
The Sulfur Cycle
The Steps of the Sulfur Cycle
1. Mineralization of organic sulfur into inorganic
forms, such as hydrogen sulfide (H2S),
elemental sulfur, as well as sulfide minerals.
2. Oxidation of hydrogen sulfide, sulfide, and
elemental sulfur (S) to sulfate (SO42–).
3. Reduction of sulfate to sulfide.
4. Incorporation of sulfide into organic
compounds (including metal-containing
derivatives).
Effects of Human Activities
on the Sulfur Cycle
• We add sulfur dioxide to the atmosphere by:
• Burning coal and oil
• Refining sulfur containing petroleum.
• Convert sulfur-containing metallic ores into free
metals such as copper, lead, and zinc releasing sulfur
dioxide into the environment.