Transcript Energy in an Ecosystem ppt

Activity #16: Energy
in a Ecosystem
EQ
• How do different organisms get the energy they
need to survive?
• How does energy move through an ecosystem?
• What are some of the roles of the organisms in
ecosystems?
Challenge Question
• Describe how energy moves through an ecosystem.
Vocabulary
•
•
•
•
•
•
•
•
•
•
Autotroph
Chemosynthesis
Heterotroph
Consumer
Carnivores
Herbivores
Omnivores
Scavengers
Decomposers
Detritivores
• Food chain
• Food web
Energy, Producers, and
Consumers
Energy
• Organisms must get energy in order to
function
• Different organisms get their energy in
different ways
• Almost all energy on Earth starts from
the sun!
1. Autotrophs
• Organisms that capture energy from
sunlight or chemicals and turn it into
food
• Also called primary producers
Primary Producers
• Most commonly use energy from the sun to
create sugars and starches (photosynthesis)
• Important examples: plants, algae,
photosynthetic bacteria
Chemosynthesis
• When primary producers turn the
energy in chemicals (like hydrogen
sulfide) into carbohydrates.
o Mostly bacteria
o Found in extreme environments (deep ocean, hot springs,
volcanoes)
2. Heterotrophs
• Eat other organisms for food.
• Also called consumers
Types of Consumers
* Put these
definitions in the
correct bubbles on
pg. 5 in the notes.
Classified by the way they acquire energy
• Carnivores- kill and eat other animals
• Herbivores- eat plant materials
• Omnivores- eat both plant and animal
materials
• Scavengers- consume carcasses of
organisms that have died or that were killed
by predators
• Decomposers- feed by chemically breaking
down organic matter into detritus, debris
from decomposing plants and animals (Ex:
fungi and bacteria)
• Detritivores- feed on detritus particles (Ex:
earthworms)
Energy Flows One Way
• Almost all energy on Earth starts from the
sun!
• Energy flows through an ecosystem in a one
way direction from producers to consumers
Food Chain
• Food Chain- a series of steps in
which organisms transfer chemical
energy by eating and being
eaten.
• food molecules are chemicals
Phytoplankton =
algae that is floating
and not attached to
something
**Read an arrow as “is eaten by”
Food Webs
• Food web- a
network of complex
interactions formed
by the feeding
relationships among
the organisms of an
ecosystem
Algae
Plants
Decomposers and Detritivores
are Important in Food Webs
• Dead plant and animal material must be
broken down so the molecules can be reused
for new life
• Decomposers (bacteria and fungi) are
heterotrophs that break down this dead plant
and animal material into detritus
o Releases nutrients into the soil for new primary
producers to grow (“recycles nutrients”)
• Detritus is eaten by detritivores (like crayfish,
grass shrimp, and worms), further releasing
nutrients into the soil
Food Web Disturbances
• Environmental
changes can
cause changes in
a food web
Krill
Think About It…
• How would a decrease in the krill population affect
the Antarctic food web?
• What do ecologists mean when they say that killer
whales indirectly depend on krill for survival?
Trophic Levels
• Each step of a food
chain or food web
is called a trophic
level
• First trophic levelalways primary
producers
• All other trophic
levels are occupied
by different types of
consumers
Ecological Pyramids
• Illustrations used to
show the amounts
of energy or matter
in each trophic
level of a food web
• Three types of
pyramids: energy,
biomass, and
numbers
Pyramids of Energy
• Show the amount of
energy available at each
trophic level
• Only 10% of the energy in
one trophic level is
passed to the next level
up.
• The rest of the energy is
either used by the
organisms to do life
processes (like growth,
reproduction, respiration,
How much of the energy available to
etc.), or released as heat
the producers is available to the
third-level consumers?
Pyramids of Biomass
• Biomass is the total amount of living tissue in
a trophic level
• Primary Producers will have the greatest
biomass
o There must be enough producers to provide
energy for all of the consumers
Pyramids of Numbers
• Show the number of
individuals at each
trophic level
• If the main producer is
a large organism, the
base of the numbers
pyramid will be small
Pyramid of Numbers
Grass
Pyramid of Numbers
Example
Phytoplankton =
algae that is floating
and not attached to
something
**Read an arrow as “is eaten by”
Example
Algae
Plants