Transcript Ecology: Energy Flow

Ecology
Ecology is the study of interactions among
organisms and between organisms and their
environment.
Ecology: Levels of Organization
Individual
Population
Community
Ecosystem
Biome
Biosphere
Ecological Methods
• Observing: simple or complex; first step in
asking ecological questions
• Experimenting: test hypotheses in a lab or in
the field
• Modeling: gain insight into complex
phenomena (global warming)
Ecological Niche
Niche defines an animal’s
lifestyle…
• habitat
• nutrition
• foraging
• territory
Niche includes everything
an animal does or uses in
order to survive.
Ecology: Energy Flow
• Every organism needs
energy.
• Sunlight is the main
energy source for life.
• Less than 1% of sunlight
is used by organisms.
• Where does the rest of the
sunlight go?
Photograph courtesy philip.greenspun.com
Ecology: Energy Flow
• photosynthesis: use of
light energy to produce
carbohydrates
• autotrophs make their
own food.
• autotrophs are producers
• Why?
Ecology: Energy Flow
• sunlight is not available
to all organisms
• chemosynthesis: use of
chemical energy to
produce carbohydrates
• most chemotrophs are
bacteria and algae
Deep sea hydrothermal vent worms
• are they autotrophs?
Ecology: Energy Flow
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autotroph: produces its own food
heterotroph: acquires energy from other
organisms
What is a producer?
What is a consumer?
Are heterotrophs producers or consumers?
consumers:
primary
secondary
tertiary
quaternary
Ecology: Energy Flow
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heterotrophs are consumers
herbivores eat plants
carnivores eat meat
omnivores eat plants and meat
insectivores eat _____________
detritivores feed on remains
decomposers break down organic matter
Where are decomposers in a food chain?
Ecology: Feeding Relationships
• Energy flows through an ecosystem in one
direction (arrows) from the sun or inorganic
compounds to producers to consumers.
• Food chain: diagram that shows simple
feeding relationships.
• Trophic level: each step in a food chain
• All food chains start with a producer.
Feeding Relationships:
Food Chain
squid (tertiary consumer)
small fish (secondary consumer)
zooplankton (primary consumer)
algae (producer)
Students be careful!
Remember: the arrow
shows the direction
energy flows in an
ecosystem.
In this example, the
Leopard seal eats the
penguin and as a result,
gets the energy.
Ecology: Feeding Relationships
• A food web is a network of
complex feeding
relationships that connects
multiple food chains.
• If one species is lost from a
food web, all other species
are affected.
Terrestrial Food Web
Aquatic Food Web
My Favorite Food Web
Matt Pendley, Buford High School, Buford, GA
Ecology: Community Interactions
Competition: when organisms try to use a
resource in short supply at the same time
and same place.
Ecology: Community Interaction
Predation: when one organism captures and eats
another organism.
Ecology: Community Interaction
Symbiosis: any relationship in which two
species live closely together.
Ecology: Symbiosis
Mutualism: when both
species benefit from the
interaction.
In this example, the sea
anemone is cleaned by
the clown fish, who in
turn is protected by the
anemone’s stinging
tentacles.
Ecology: Symbiosis
Commensalism: when
one species benefits
from the interaction
and the host species is
unaffected.
The leafy plant is an
epiphyte, growing on
another plant only for
support.
Ecology: Symbiosis
Parasitism: interaction
in which one organism
benefits and the other
organism (host) is
harmed.
Asian tiger mosquito
Does the host die as a
result?
Ecological Pyramids: Energy Pyramid
(energy flow in a community)
• each trophic level
represents a different
group of organisms in a
food chain
• about 10% of the energy
available at each trophic
level is transferred to
organisms at the next
trophic level
• energy is lost as heat and
in life processes
Ecological Pyramids: Biomass Pyramid
• biomass is the total amount of living tissue
• expressed as grams of organic matter per unit area
• biomass pyramid represents the potential amount of
food available at each trophic level
• normally the greatest biomass is at the base
Ecological Pyramids: Numbers Pyramid
• based on the numbers of
individuals at each
trophic level
• some number pyramids
look like biomass &
energy pyramids, some
do not
• in this example, the oak
tree has a large amount of
energy and biomass, but it
is only one organism
Laws of Ecology
All things are interconnected.
Everything goes somewhere.
There’s no such thing as a free lunch.
Nature bats last.
Ecology: A Pocket Guide by Ernest Callenbach