Ecology
2e- Biogeochemical Cycles
(Ecosystem Recycling)
Bellwork!
• What is carrying capacity?
• Mark carrying capacity on this graph:
• Tell me the trophic level of each animal in this
food chain:
– Lettuce, Bunny, Fox, Wildcat
• 3rd block: what is the difference between
primary and secondary succession?
Carrying Capacity, Notice!!
• Carrying Capacity not at top!!
• Its where we have survivors..
Important Dates
• Today: Intro/materials and methods due
– If you didn’t turn in, you have until 12 am tonight to
send it to me by email,
[email protected]
• Wed: Computer Day, Results and Discussion.
• Thursday: Study Guides Due
• Friday (as of now..): test
– I’m going to extend your draft final lab report until
Monday 2/16 (Intro, Materials/Methods, Results,
Discussion, Sources)
Standards:
• B-3.6 Energy Flow, Chains, Webs and Pyramids:
Illustrate the flow of energy through ecosystems
(including food chains, food webs, energy
pyramids, number pyramids, and biomass
pyramids).
• B-6.4 Geochemical Cycles: Exemplify the role of
organisms in the geochemical cycles (including
the cycles of carbon, nitrogen, and water).
Objectives
• I can illustrate the flow of energy through a
food chain in an ecological pyramid!
• I can explain how ecosystems (living and
nonliving components) change over time to
generate stability.
Biogeochemical Cycles
• Matter cannot be created or destroyed, it can only
change forms.
• Matter placed into biological systems is always
transferred and transformed.
– Substances, like carbon, nitrogen, and water, get cycled in
and out of ecosystems.
• Biogeochemical Cycles: the movement of a
particular form of matter through the living and
nonliving parts of an ecosystem
Carbon Cycle
• Carbon is one of the major components of the biochemical
compounds in living organisms.
– proteins, carbohydrates, lipids, nucleic acids
• Carbon is found in the atmosphere (as CO2) and in many
minerals, rocks, fossil fuels (natural gas, petroleum, and coal)
and in the organic materials that compose soil and aquatic
sediments.
• Organisms play a major role in recycling
carbon from one form to another in the
following processes:
– Photosynthesis
– Cellular Respiration
– Decomposition
– Conversion of biochemical
compounds
Carbon Recycling Processes
1. Photosynthesis:
Autotrophs use CO2,
along with water & solar
energy, to make
carbohydrates.
2. Cellular Respiration:
Autotrophs &
heterotrophs use O2 to
breakdown
carbohydrates.
– The byproducts are CO2
and H2O.
Carbon Recycling Processes
3. Decomposition: Decomposers release CO2 into the
atmosphere when they break down organic
compounds.
4. Conversion of biochemical compounds: Organisms
store carbon in their bodies. When animals eat,
those carbon-containing compounds can be:
– used for energy
– converted to compounds that are
suited for the predator’s body
– released to the atmosphere as methane
and other gases
DeSalle and Heithaus
Human Influences on the Carbon Cycle
• Combustion: the burning of fossil fuels and
other organic matter
– Fossil Fuels: the remains of organisms that
have been transformed by decay, heat, &
pressure into energy-rich molecules
– Burning releases the energy + CO2
Nitrogen Cycle
• All organisms need nitrogen to make proteins &
nucleic acids.
• Nitrogen gas (N2) makes up about 78% of the
atmosphere
– Nitrogen is also found in living organisms & organic
materials that compose soil and aquatic sediments.
• Organisms play a major role in recycling nitrogen
from one form to another in the following processes:
– Nitrogen-fixation
– Intake of nitrogen into the
organisms
– Decomposition
– Denitrification
Nitrogen Recycling Processes
1. Nitrogen-fixation:
– Most plants can only use nitrogen in the form of nitrate
(NO3)
– Nitrogen-fixing bacteria live in the soil & inside plant roots
and transform nitrogen gas (N2) into a usable form.
– The plants supply carbohydrates for the bacteria.
2. Intake of nitrogen: Plants
take in the nitrogen through
their root systems and in this
way, nitrogen can enter the
food chain
Nitrogen Recycling Processes
3. Decomposition: When an organism dies or from
animal waste products, decomposers return
nitrogen to the soil.
4. Denitrification: Denitrifying bacteria break down
nitrates in the soil and release nitrogen gas into the
atmosphere.
Water Cycle
• Water is a necessary substance for the life processes of all
living organisms.
• The water cycle, also called the hydrologic cycle, is driven by
the Sun’s heat energy, which causes water to evaporate from
water reservoirs, condense into clouds, and then precipitate
back to water bodies on Earth.
• Organisms also play a role in recycling
water from one form to another by:
–
–
–
–
Intake of water into the organisms
Transpiration
Respiration
Elimination
Water Recycling Processes
DeSalle and Heithaus
1. Intake of water : Organisms take in water and use it to
perform life functions
2. Transpiration: The evaporative loss of water from plants.
3. Cellular Respiration: All organisms metabolize
food for energy and produce water as
a by-product.
4. Elimination: Most organisms need
water to assist with the elimination
of waste products.
Recap: so what cycles did we talk
about today?
• What three things that cycle through the
environment provide living organisms the
ability to..live?
– Carbon
– Nitrogen
– Water