WARM UP  What do you call the first level of a food pyramid? –Primary consumer –Producer –Secondary consumer –Tertiary consumer

Chapter 5 How Ecosystems Work

Chapter 5 Section 1 : Energy Flows in Ecosystem

Energy  Flow of energy through ecosystem is one of the most important factors that determines the system’s capacity to sustain life  Without a constant supply of energy an organism cannot survive

Producers  Sunlight main energy source for life on Earth  Less than 1% of sun’s energy that reaches Earth is used  Some organisms use stored energy in inorganic chemicals  Producers- organisms that make their own food from sunlight or inorganic chemicals –Also called autotrophs

Energy From the Sun  Converts sunlight to chemical energy through photosynthesis  Adds oxygen to the atmosphere  Takes carbon dioxide from atmosphere  On land plants are main autotrophs  In freshwater and marine ecosystems algae are main autotrophs  In wetlands photosynthetic bacteria are main autotrophs

Life Without Light  Relies on energy within inorganic molecules –Chemosynthesis –Performed by bacteria Exist in large numbers –Live on volcanic vents on ocean floor, hot springs and wetlands

Consumers  Get energy from other organisms –By consuming them  Called heterotrophs –Types: Herbivores- plant eaters Carnivores- meat eaters Omnivores- eat both Detritivores- eat dead matter Decomposers- break down organic matter

Feeding Relationships  Energy moves in a one way path through ecosystems –Sun to autotroph to consumers  Relationships are based on who eat whom

Food Chains  Series of steps in which energy is transferred by eating and being eaten  Contains one organism at each step

Food Webs  Complex network of food chains  Multiple organisms at each step

Trophic Levels  Each step in a food web or chain –Producers make up 1 st trophic level –Consumers make up 2 nd, 3 rd and higher levels

Ecological Pyramids  Diagram that shows the relative amounts of energy or matter contained within each trophic level in a food chain or web  Three types: –Energy pyramids –Biomass pyramids –Numbers pyramid

Energy Pyramids  Only part (10%) of energy stored in one trophic level is passed on to the next  Most used to perform life functions  Rest released as heat

Biomass Pyramid  Total amount of living tissues within a trophic level is called biomass  Represents total amount of potential food available for each trophic level in an ecosystem

Numbers Pyramid  Based on numbers of individuals at each trophic level  This pyramid is not always in pyramid shape

Warm Up – Monday 3/4  What does a biomass pyramid show?

Chapter 5 Section 2: Cycles of Matter

Needs of an Organism  All organisms need more than energy to survive –They need: Water Minerals Life sustaining compounds  More than 95% of the body is made up of: –Oxygen –Carbon –Hydrogen –Nitrogen

Recycling in the Biosphere  Matter is recycled within and between ecosystems  Passed through biogeochemical cycles  Matter is transformed as it is recycled –The air you breath may have been once been inhaled by a dinosaur

The Water Cycle  All living things require water  Moves between oceans, atmosphere and land  Evaporates from oceans and lakes or transpires from leaves, enter the atmosphere and condenses to form precipitation, excess water runs off to form streams which run into oceans or lakes

Nutrient Cycles  Nutrients- –All chemical substances that an organism needs to sustain life –Needed to build tissues and carry out essential life functions –Carbon cycle, nitrogen cycle and phosphorus cycle all cycle nutrients

Carbon Cycle  Carbon key ingredient in living tissue –Biological processes such as photosynthesis, respiration and decomposition take up and release carbon and oxygen –Geochemical processes, such as erosion and volcanic activity, release carbon dioxide to the atmosphere and oceans –Mixed biogeochemical processes, such as the burial and decomposition of dead organisms and the conversion under pressure into coal and petroleum, store carbon underground –Human activities, such as mining, cutting and burning forests

Nitrogen Cycle  All organisms require nitrogen to build amino acids –Only certain types of nitrogen are able to be used by organisms –Bacteria can use nitrogen gas and convert it to ammonium, nitrates and nitrites through nitrogen fixation –Producers use these forms of nitrogen to build proteins –Consumers eat the producers and make their own proteins –Decomposing organisms return nitrogen to the soil as ammonium –Some of this ammonium is used by producers, some converted back to nitrogen gas by bacteria

Phosphorus Cycle  All organisms require phosphorus to make DNA and RNA –Not common in atmosphere –Remains in rocks, minerals and ocean sediments –Some washed into streams with runoff Used by marine organisms –Some is used by producers, bind phosphates to organic compounds –Consumers eat the producers and obtain phosphorous

Nutrient Limitation  Primary productivity –Rate at which organic matter is created by producers  Affected by available nutrients –If nutrient is in short supply it is a limiting nutrient

Chapter 5 Section 3 : How Ecosystems Change

Ecological Succession  Ecosystems and communities are always changing in response to natural and human disturbances –Older inhabitants die out –New organisms move in causing more change

Primary Succession  Occurs on surfaces where no ecosystem has existed before –Lava field –Bare rock exposed by glacier melt  1 st species are pioneer species –Lichens move in an break down rock into soil –As lichens die they add organic matter to soil

Secondary Succession  Occurs on surfaces where soil already exists –Plowed fields –Burned woodlands  Grasses begin to grow  Shrubs begin to grow  Trees begin to grow  Will eventually form a mature stable ecosystem –Climax community

Pioneer Species  First species to populate an area

- species that influences the survival of many other species Bats are considered keystone species of many ecosystems. KEYSTONE SPECIES