Name: _______________________________
ECOLOGY
3-1 What is Ecology?
Ecology is the scientific study of
interactions among organisms and
between organisms and their
environment, or surroundings.
– Many levels
– Biosphere is alll of life
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The study of ecology ranges from the
study of an individual organism to
populations, communities, ecosystems,
biomes—and, finally, to the entire
biosphere.
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Some ecologists study interactions between a particular kind of organism
and its surroundings. Such studies focus on the species level. A species is a
group of organisms so similar to one another that they can breed and
produce fertile offspring. Other ecologists study populations, or groups of
individuals that belong to the same species and live in the same area. Still
other ecologists study communities, or assemblages of different populations
that live together in a defined area.
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Ecologists may study a particular ecosystem. An ecosystem is a collection
of all the organisms that live in a particular place, together with their
nonliving, or physical, environment. Larger systems called biomes are also
studied by teams of ecologists. A biome is a group of ecosystems that have
the same climate and similar dominant communities. The highest level of
organization that ecologists study is the entire biosphere itself.
ECOLOGY Practice Set #1
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3-2 Energy Flow
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Sunlight is the main energy source for life on Earth.
– Autotrophs directly use sun’s energy (Photosynthesis) to make energy
supply
• Aka Producers
– Heterotrophs consume other organisms for energy supply
• Aka Consumers
• Heterotroph types
– Herbivores
• Primary (1) Consumers
– Carnivores
• Secondary (2) Consumers
– Omnivores
– Detritivores
• Decomposers
The energy stored by producers can be passed through an ecosystem
along a food chain, a series of steps in which organisms transfer energy by
eating and being eaten.
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A food web links all the food chains in an ecosystem together.
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Each step in a food chain or food web is called a trophic level. Producers
make up the first trophic level. Consumers make up the second, third, or
higher trophic levels. Each consumer depends on the trophic level below it
for energy.
ECOLOGY Practice Set #2
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An ecological pyramid is a diagram that shows the relative amounts of
energy or matter contained within each trophic level in a food chain or
food web.
– Can look at
• Energy
• Biomass
• Numbers
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The 10% Rule
– When you go up a trophic level, only 10% of the previous level’s ______
is available.
• Could be energy, mass, or numbers
3-3 Cycles of Matter
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Unlike the one-way flow of energy, matter is recycled within and between
ecosystems. Elements, chemical compounds, and other forms of matter are
passed from one organism to another and from one part of the biosphere
to another through biogeochemical cycles.
– C, H2O, N are key ones
Summary of the Water Cycle
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Summary of the Carbon Cycle
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Summary of the Nitrogen Cycle
ECOLOGY Practice Set #3
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When an ecosystem is limited by a single nutrient that is scarce or cycles
very slowly, this substance is called a limiting nutrient.
– Nitrogen and Phosphorus major ones
– Too much nutrients? Algal bloom
4-1 The Role of Climate
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Carbon dioxide, methane, water vapor, and a few other atmospheric
gases trap heat energy and maintain Earth's temperature range
4-2 What Shapes an Ecosystem?
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The biological influences on organisms within an ecosystem are called
biotic factors. These include the entire living cast of characters with which
an organism might interact, including birds, trees, mushrooms, and
bacteria—in other words, the ecological community.
Physical, or nonliving, factors that shape ecosystems are called abiotic
factors . For example, the climate of an area includes abiotic factors such
as temperature, precipitation, and humidity.
Community interactions, such as competition, predation, and various forms
of symbiosis, can powerfully affect an ecosystem.
ECOLOGY Practice Set #4
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5-2 Limits to Growth
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In the context of populations, a limiting factor is a factor that causes
population growth to decrease.
Predation Populations in nature are often controlled by predation. The
regulation of a population by predation takes place within a predator-prey
relationship, one of the best-known mechanisms of population control. The
relationships between sea otters and sea urchins and between sea otters
and killer whales are examples of predator-prey interactions that affect
population growth.
ECOLOGY Practice Set #5
5-3 Human Population
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Exponential Growth
6-1 A Changing Landscape
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Among human activities that affect the biosphere are hunting and
gathering, agriculture, industry, and urban development.
6-2 Renewable and Nonrenwable Resources
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Renewable resources can regenerate if they are alive, or can be
replenished by biochemical cycles if they are nonliving.
– Water, wind, sun
A nonrenewable resource is one that cannot be replenished by natural
processes.
– Fossil fuels (reasonable rate)
– Uranium Ore
Human activities can affect the quality and supply of renewable resources
such as land, forests, fisheries, air, and fresh water.
6-3 Biodiversity
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Biological diversity, or biodiversity, is the sum total of the genetically based
variety of all organisms in the biosphere.
– 3 Levels
• Ecosystem diversity
• Species diversity
• Genetic diversity
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Human activity can reduce biodiversity by altering habitats, hunting
species to extinction, introducing toxic compounds into food webs, and
introducing foreign species to new environments.
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Habitat destruction decreases numbers
– Threatened < Endangered < Extinct
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Pollution accumulates in food chains
– In this process, called biological magnification,
concentrations of a harmful substance increase
in organisms at higher trophic levels in a food
chain or food web.
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DDT was a pesticide
– Fat soluble
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Invasive species increase their populations because
their new habitat lacks the parasites and predators
that control their population “back home.”
ECOLOGY Practice Set #6
6–4 Charting a Course for the Future
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The Ozone layer is part of our atmosphere that contains ozone (O3). It
blocks UV radiation
– Ozone layer damaged due to use of CFCs (coolants/propellants)
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The overall trend of the warming of the planet solely due to anthropogenic
causes is called Global Warming.
– Man causes: CO2 from combustion
• Higher amounts of GHGs
– Effects
• Ocean rising
• Decrease in biodiversity