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Matter And Energy In The Ecosystem
Ecology is the study interactions among living things, and between living things and their natural surroundings).
Ecological research methods include observation, experimentation, and modeling.
Observation is the act of carefully watching something over time.
Observations of populations can be done by visual surveys.
Experiments are performed in the lab or in the field.
Computer and mathematical models can be used to describe and model nature.
Ecologists study environments at different levels of organization.
Biotic factors
All living things (plants, animals, bacteria, fungi, etc.)
Products of living things (wood, waste, etc.)
Abiotic factors
Gases (oxygen, nitrogen)
soil
Water/ moisture
pH
Minerals
Sunlight
Temperature
Wind
Ecosystem Services
Important environmental benefits that ecosystems provide, such as:
Clean air to breathe, filtered by plants
Clean water to drink, filtered underground
Fertile soil in which to grow crops
Pollinators and agriculture, production of food!
Mangroves: protection from storms, nurseries
Producers provide energy for other organisms in an ecosystem.
Producers get their energy from non-living resources
Producers are also called autotrophs because they make their own food.
Producers (when consumed) provide energy for other organisms in an ecosystem.
Consumers are organisms that get their energy by eating other living or once-living resources.
Almost all producers obtain energy from sunlight.
Photosynthesis in most producers uses sunlight as an energy source.
Sunlight + water + CO2 -> glucose + water + O2
Chemosynthesis in prokaryote producers uses chemicals as an energy source.
A food chain is a model that shows a sequence of feeding relationships.
A food chain links species by their feeding relationships.
A food chain follows the connection between one producer and a single chain of consumers within an ecosystem.
Consumers are not all alike.
Specialists are consumers that primarily eat one specific organism or a very small number of organisms. (ex.
Everglades Snail Kite below)
Trophic levels are the nourishment levels in a food chain.
A food web shows a complex network of feeding relationships.
An organism may have multiple feeding relationships in an ecosystem.
A food web emphasizes complicated feeding relationships and energy flow in an ecosystem.
Changing one factor in an ecosystem can affect many other factors.
Biodiversity is the assortment, or variety, of living things in an ecosystem.
Rain forests have more biodiversity than other locations in the world, but are threatened by human activities.
Official video of the International Year of Biodiversity 2010
A keystone species is a species that has an unusually large effect on its ecosystem.
Keystone species form and maintain a complex web of life.
Active Figure: Roles of organisms in an ecosystem
3 Biotic Components of an Ecosystem, (“Role” of Organisms)
Producers: make their own food, photosynthetic plants (i.e. trees, algae, phytoplankton, grasses)
Consumers: need to consume others to get energy
Carnivores: eat meat (dogs, cats)
Herbivores: eat plants (cattle, deer, horses)
Omnivores: eat both (chimpanzees, bears, humans)
Scavengers: feed on “carrion”, dead animal remains
(vultures, hyenas)
Decomposers: break down organic material at the microscopic level and recycle nutrients, feed on detritus (dead
material)
(i.e. fungi, worms, bacteria) Animation
The_Food_Chain__Predators_and_Prey
Transfer of Energy
Capture of sun energy transfer through different trophic levels.
Capture of essential elements of life and transfer through different steps or energy levels called: trophic levels.
Food Webs and Energy Flow in Ecosystems
Food Chains & Food Webs
Food chains: series of organisms that transfer food between trophic levels in an ecosystem
many food chains exist in an ecosystem, all of these form a complex food web
Some food webs are very fragile, break one food chain and the rest may fall apart.
Things that harm food webs: pollution, human activity, natural disasters, etc.
Match Organisms With Trophic Level(s)
Match Organisms With Trophic Level(s)
Trophic Relationships Among Producers and Consumers
Trophic Categories and Terminology
BIOMASS
Biomass: total amount of organic matter present in a particular trophic level
The 10% law: Energy is lost at each trophic level, not all that you eat becomes biomass. Only about 10% of energy
is turned into biomass, reason why most food chains only have 5 - 6 trophic levels.
Energy and Food
Ecological Pyramid: diagram showing the relative amounts of energy, # of organisms and biomass at different levels
Trophic Levels: Pyramid of Biomass
Trophic Levels
BIOMASS, ENERGY AND ABUNDANCE OF ORGANISMS
What happens to # of organisms as you move up pyramid?
What happens to biomass as you move up pyramid?
What happens to energy as you move up pyramid?
An energy pyramid shows the distribution of energy among trophic levels.
Energy pyramids compare energy used by producers and other organisms on trophic levels.
Ecological pyramid also show an ecosystem’s biomass and distribution of organisms.
Biomass is a measure of the total dry mass of organisms in a given area.
A pyramid of numbers shows the numbers of individual organisms at each trophic level in an ecosystem.
BIOMAGNIFICATION
In a ecological pyramid, as you move up trophic levels concentrations of toxins and pollutants increase organisms at
higher trophic levels
ex. DDT and eagles
ex. mercury in Everglades bass
ex. lead poisoning and the fall of the Roman empire
Elements essential for life also cycle through ecosystems.
Nutrient cycles.
A biogeochemical cycle is the movement of a particular chemical through the biological and geological parts of an
ecosystem
The main processes involved in the oxygen cycle are photosynthesis and respiration.
Human impacts on cycles?
Oxygen cycles indirectly through an ecosystem by the cycling of other nutrients.
MATTER CYCLING IN ECOSYSTEMS
Chemical Cycles
water cycle: more than 95% of fresh water in U.S. is locked under surface. Fortunately, water follows a cycle, water
moves between oceans, land and atmosphere.
Evaporation: movement of water into atmosphere, liquid to gas
Transpiration: evaporation of water from leaves of plants
Hydrologic Cycle
Describes the circulation of water as it:
Evaporates from land, water, and organisms. (Transpires from plants)
Enters the atmosphere
Condenses and precipitates back to the earth’s surfaces.
Moves underground by infiltration or overland runoff into rivers, lakes and seas.
Hydrologic Cycle
Solar energy drives the hydrologic cycle by evaporating surface water.
Evaporation - Changing liquid to a vapor below its boiling point.
Condensation - Changing water from gaseous liquid state.
Precipitation - Rain, snow, sleet, hail.
Transpiratrion - water given off my plants
Perspiration - water given off by organisms
Precipitation Patterns
Carbon is the building block of life.
THE NITROGEN CYCLE
- living things require nitrogen to make amino acids (protein). Nitrogen abundant in atmosphere but we cannot use
directly, need a different chemical form. Only some types of organisms (bacteria) use directly from atmosphere
(called nitrogen-fixing bacteria). These bacteria exist in soils and on plant roots
Legumes: plants that have colonies of nitrogen fixing bacteria in nodules on their roots. ex. clover, peanuts
The nitrogen cycle mostly takes place underground.
What is a ecological pyramid? Draw one!
What is a consumer (heterotroph)? Describe/define 4 different types, give examples.
What are the 3 roles/categories organisms fall into? Describe/define each, give examples.
What is a keystone species? Examples. Why are they important?
What 2 ways can producers make their own food? Describe/explain, give examples.
Compare/contrast a generalist vs. a specialist. Give examples.
Compare/contrast abiotic vs. biotic factors. What drives it?
Describe the water cycle (each of the steps), what drives it?