Transcript PPT - Learn District 196

Biology
Ecology Unit
Energy in Ecosystems
 Consumers: get their energy by
eating other living or onceliving resources such as plants
or animals
 Also called heterotrophs
 Producers: get their energy
from nonliving resources,
meaning they make their own
food.
 Also called autotrophs
Energy in Ecosystems
 Some organisms make food
without sunlight 
 Chemosynthetic Organisms
 Even animals that eat only
meat rely on producers
 Grey Wolf: Eats Elk and
Moose, but
 Elk and Moose eat
grasses and shrubs
Food Chains and Food Webs
 Types of Consumers:
 Herbivores: only eat plants
 Carnivores: only eat animals
 Omnivores: eat both plants and animals
 Detritivore: an organism that eats
“detritus”, or dead organic matter.
 Decomposers: detritivores that break
down organic matter into simpler
compounds
 Specialists: a consumer that primarily
eats on specific organism or feeds on a
very small number of organisms
 Generalists: consumers that have a
varying diet
Food Chains and Food Webs
 Trophic Levels:
 Producers: plants
 Primary Consumers: herbivores
 Secondary Consumers: carnivores
that eat herbivores
 Tertiary Consumers: carnivores that
eat secondary consumers
 Omnivores, such as humans, may
be listed at different levels in
different food chains
Food Chains and Food Webs
 Food Chain: A sequence that
links species by their feeding
relationships.
Food Webs and Food Chains
 Food Web: a model that
shows the complex
network of feeding
relationships and the
flow of energy within an
ecosystem
 An organism may have
multiple feeding
relationships within a
food web
Cycling of Matter
 Hydrologic Cycle/Water Cycle:
the circular pathway of water
on Earth
 Atmosphere  Surface  Below
the Ground  Back into the
Atmosphere
Biogeochemical Cycles
 Biogeochemical Cycle: the movement of a particular
chemical through the biological and geological, or
living and nonliving, parts of an ecosystem.
 1. Oxygen Cycle
 2. Carbon Cycle
 3. Nitrogen Cycle
 4. Phosphorus Cycle
Biogeochemical Cycles
 The Oxygen Cycle
 -Plants, animals, and most
other organisms use oxygen
for cell respiration
 -Plants release oxygen as a
waste product
Biogeochemical Cycles
 The Carbon Cycle
 -Carbon continually flows from
the environment to living
organisms and back again in the
carbon cycle
 -Sources of Carbon:
 CO2 in the atmosphere
 Bicarbonate (HCO3) dissolved in
water
 Fossil Fuels
 Carbonate Rocks
 Dead organic matter
Biogeochemical Cycles
 The Nitrogen Cycle
 -78% of Earth’s atmosphere is
made up of Nitrogen
 Much of the nitrogen cycle
occurs underground
– Some bacteria convert gaseous
nitrogen into ammonia through a
process called nitrogen fixation.
– Some nitrogen-fixing bacteria live
in nodules on the roots of plants;
others live freely in the soil.
Biogeochemical Cycles
 Nitrogen Cycle Continued…
 Ammonia released into the soil
is transformed into ammonium.
 Nitrifying bacteria change the
ammonium into nitrate.
 Nitrogen moves through the
food
web and returns
to the soil during
decomposition.
Biogeochemical Cycles
 Phosphorus Cycle
 The phosphorus cycle takes place
at and below ground level.
 Phosphate is released by the
weathering of rocks.
 Phosphorus moves through the
food web and returns to the soil
during decomposition.
 Phosphorus leaches into
groundwater from the soil and is
locked in sediments.
 Both mining and agriculture add
phosphorus into the environment.
Pyramid Models
 Pyramids model the distribution of
energy and matter in an
ecosystem.
 Three types of pyramids:
 1. Energy Pyramid
 2. Biomass Pyramid
 3. A Pyramid of Numbers
1. Energy Pyramid
 Energy Pyramids compare
energy used by producers,
primary consumers, and
other trophic levels.
 Between each tier, up to
90% of the energy is lost as
heat into the atmosphere.
 Shows the important role
producers play in an
ecosystem.
2. Biomass Pyramid
 Biomass pyramids compare the
biomass of different trophic levels
within an ecosystem.
 Biomass: a measure of the total
dry mass of organisms in a given
area. (g/m2)
 Shows the important role
producers play in an ecosystem.
3. A Pyramid of Numbers
 A pyramid of numbers
shows the number of
individual organisms at
each trophic level in an
ecosystem
 Shows the important role
producers play in an
ecosystem.
 http://my.hrw.com/hssc_2012/hmd_na_bio/nsmedia/that
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