Mrs. Geist
Biology, Fall 2010-2011
Swansboro High School
How do organisms obtain energy?
 Energy: the ability to cause change or do work
 Obtaining Energy
 Producers: make their own food. A.k.a. autotrophs.
 Consumers: eat other organisms. A.k.a heterotrophs.
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Herbivores: eat producers, such as plants and green algae (ex:
cow)
Carnivores: eat other consumers (ex: wolf)
Omnivores: eat both producers and consumer (ex: humans)
Scavengers: eat animals that have already died (ex: vulture)
Decomposers: break down dead or decaying organisms (ex:
fungi, some bacteria)
Flow of Matter and Energy in
Ecosystems
 Food chain: a model that scientists use to trace the
flow of energy and matter (i.e. nutrients) in an
ecosystem.
 Ex: sun  grass  cows  human  wolf  bear 
vultures
 Energy source  producer  primary consumer 
secondary consumer  tertiary consumer  scavenger
 Food web: complex model of overlapping food chains
 Energy pyramid: amount of available energy
decreases as you go up in trophic levels
Food Web
www.tutorvista.com
Energy Pyramid
http://www.mesa.edu.au
Water Cycle
 Evaporation: water from lakes and oceans becomes
water vapor in the air
 Condensation: water vapor condenses on dust in the
air and forms clouds
 Precipitation: further condensation results in rain,
ice, or snow
 Natural Processes recycle water
 Plants and animals need water for survival.
 Plants lose water through transpiration.
 Animals breathe out water vapor and perspire or urinate.
Water Cycle
Carbon Cycle
 Photosynthesis: autotrophs utilize sun and CO2 gas
to form sugars
 Heterotrophs feed directly or indirectly on
autotrophs to obtain carbon.
 Cellular respiration releases energy from glucose and
releases CO2 back into the air.
Carbon Cycle
Ecology
 Ecology: the study of the relationship between living
things and their environment
 Habitat: where an organism lives
 Niche: strategies and adaptations a species uses in its
environment
 Obtaining food and shelter
 How and where it survives
 Where it reproduces
 No two species can occupy the same niche at the same
time
Symbiosis
 Symbiosis: close relationship between 2 organisms. 3
types:
 Mutualism: both organisms benefit.
 Commensalism: one organism benefits; the other is
neither harmed nor helped.
 Parasitism: one organism benefits; the other is harmed
 Test your knowledge with the “Symbiosis Worksheet”
Levels of Organization in an
Ecosystem
 Organism: a living thing
 Population: a group of organisms of the same species
living in the same area at the same time
 Community: all of the populations of a different species in
the same place at the same time
 Ecosystem: living organisms that interact with each other
and the abiotic factors in a given area
 Biotic: living things. Ex: plants and animals
 Abiotic: non-living things. Ex: temperature, climate, soil,
rocks.
 Biosphere: the life-supporting portion of Earth
Levels of
Organization
in an
Ecosystem
Carrying Capacity
 Carrying capacity: the amount of organisms an
environment can support
 Limiting factors: any biotic or abiotic factor that
restricts the existence, numbers, reproduction, or
distribution of organisms.
 Ex: elevation, temperature, climate, soil chemistry,
space, water, nutrients/food, sunlight
 Tolerance: an organism’s ability to withstand
fluctuations in biotic and abiotic environmental
factors
Succession
 Primary succession: occurs on an area of newly exposed
rock or sand or lava or any area that has not been occupied
previously by a living (biotic) community.
 First species to arrive are called pioneer species.
 Ex: lichens (algae and fungus living together)
 Secondary succession: takes place where a community
has been removed
 ex: in a plowed field or a cleared forest
 Climax community: populations of plants or animals
remain stable and exist in balance with each other and
their environment.
 Final stage of succession
Primary Succession
Secondary Succession
Factors affecting Population size
 Density-independent factors: affect the population
in the same proportion no matter the number of
individuals (population size).
 Density-dependent factors: affect the population
more or less depending on the population size