Gateway Review Chemistry Ecology Review

Energy Flow flow of energy through an ecosystem flow: Producers  Consumers  Decomposers Food Chains – series of steps in which one organism transfers energy by eating and being eaten Food Web – network of food chains in an ecosystem showing the complex interactions between organisms In order to live, organisms must obtain energy and nutrients Heterotrophs – obtain energy and nutrients from the food they eat Autotrophs – obtain energy from the sun/obtain nutrients from the soil

Law of Conservation of Energy Energy cannot be created or destroyed – it can only change forms. Energy moving through food chain/web only 10% available for next level up rest is used for energy to carry out life functions, increase body mass, and lost as heat

Producers organisms that make their own food – use energy from the sun and carbon from the environment “bottom of the food chain” process of making food = Photosynthesis 6 CO H 2 O + light energy  C 6 H 12 O O 2 requires carbon dioxide, water and energy (sunlight) makes sugars and gives off oxygen gas Why are producers necessary in an ecosystem?

Photosynthesis Process of using energy from the sun to produce sugars (glucose) 6 CO H 2 O + light energy  C 6 H 12 O O 2 Occurs in chloroplast of plants and some algae

Consumers organisms that cannot make their own food – obtain energy through eating other organisms Herbivore – eats only plants Carnivore – eats only animals Omnivore – eats both plants and animals several levels in food chains (food webs) primary – eat only producers secondary and higher – eat other consumers that eat the producers decomposers – eat dead matter, recycle nutrients for producers to use again Means of obtaining nutrition Predation Ecological interaction in which one organism (predator feeds on another living organism (prey) Predator may or may not kill the prey Scavenging An animal ingests dead plants, animals, or both (vultures, termites, beetles) Decomposer (saprophytes) Break down (absorb nutrients from) nonliving organic material – corpses, plants, waste of living organisms- and convert them to inorganic forms (bacteria, fungi) use cellular respiration to break down food into energy and nutrients 6 O 2 + C 6 H 12 O 6  6 CO H 2 O + energy reverse reaction of photosynthesis

Respiration Process of using energy from sugar (glucose) to produce ATP C 6 H 12 O O 2  6 CO H 2 O + 38 ATP Occurs in mitochondria Occurs in both animals and plants ATP provides energy to do work in the cell When ATP is used, it is converted to ADP; respiration then uses energy in sugars to convert ADP back to ATP by adding a phosphate How are photosynthesis and respiration related?

Food Web & Food Chains Review 1. List 3 food chains within the food web above. A B C 2. Using the three food chains just listed above, list the producers. 3. Using the three food chains just listed above, list the first order consumers. 4. Using the three food chains just listed above, list the carnivores. 5. Using the three food chains just listed above, list the second order consumers.

Carbon Cycle Carbon: key ingredient in all living things Processes involved: Biological (photosynthesis) Geochemical (release of CO 2 by volcanoes) Human activity (burning of fossil fuels)

Carbon Cycle You take in carbon in the foods you eat  return CO 2 to the air when you exhale A plant also returns CO 2 to the air when it uses its own sugars as a source of energy  another plant takes in CO 2 during photosynthesis = complete cycle of carbon within a community

Carbon Cycle Hundreds of millions of years ago plant bodies buried before decomposers got to them  they became sources of fuel (coal, oil, natural gas)  today, fuels are burned and energy is released  the carbon in the fuels is returned to the air as CO 2 Carbon passed from one organism to another  abiotic community  back to the plants = carbon cycle

The Carbon (CO 2 ) Cycle Carbon enters food chains through photosynthesis. Plants in land ecosystems absorb carbon dioxide into their leaves from the air and use it to make organic matter, which accumulates as plant tissue (biomass). The carbon is then passed along food chains as organic matter. Carbon is released from food chains back into the atmosphere through cellular respiration Plants, animals and decomposers all release carbon dioxide, and the carbon cycle is complete. Note: Carbon cycles at a fast rate. However, some carbon atoms get stored for millions of years as coal, oil and natural gas. Coal and oil are formed from partially decomposed fossil remains of organisms. Natural erosion, volcanic activity and fire eventually release carbon from these stores.