9.4.2.2 Cycles & Energy Flow

• NSES Standards:

Plant cells contain chloroplast, the site of photosynthesis.  Plants and many microorganisms use solar energy to combine molecules of carbon dioxide and water into complex, energy rich organic compounds and release osygen to the environment.  The process of photosynthesis provides a vital connection between the sun and the energy needs of living systems. (pg 184)

The atoms and molecules on the earth cycle among the living and nonliving on the earth cycle among the living and nonliving components of the biosphere. (pg 186)

Energy flows through ecosystems in one direction, from photosynthetic organisms to herbivores to carnivores and decomposers. ( pg 186)

The energy for life primarily derives from the sun.  Plant capture energy by asboring light and using it to form strong (covalent) chemical bonds between the atoms of carbon containing organic molecules.  these molecules can be used to assemble larger molecules with biological activity ( including proteins, DNA sugars and fats).  In addition, the energy stored in bonds between the atoms (chemical energy) can be used as sources of energy for life processes. Pg 186

• AAAS Atlas:

See Benchmarks below. 

Benchmarks of Science Literacy

Plants alter the earth's atmosphere by removing carbon dioxide from it, using the carbon to make sugars and releasing oxygen.  This process is responsible for the oxygen content of air. (pg 74)

Benchmark 5E/3 The chemical elements that make up the molecules of living things pass through food webs and are combined and recombined in different ways.  At each link in a food web, some energy is stored in newly made structures but much is dissipated into the environment as heat.  Continual input of energy from sunlight keeps the process going. pg 121

Framework for K-12 Science Education

The process of photosynthesis converts  light energy to stored  chemical energy by converting  carbon  dioxide  plus water  into sugars plus released oxygen. The sugar molecules thus formed  contain  carbon,  hydrogen, and oxygen; their hydrocarbon backbones  are used to make amino  acids and other  carbon-based molecules that  can be assembled  into larger molecules (such as proteins  or DNA), used for example  to form new cells. As matter  and energy flow through different  organizational levels of living systems, chemical elements are recombined in different  ways to form different  products. As a result of these chemical reactions,  energy is transferred from one system of interacting  molecules to another. For example,  aerobic  (in the presence of oxygen) cellular respiration is a chemical process in which the bonds  of food molecules and oxygen molecules are broken  and new compounds are formed  that  can transport energy to muscles. Anaerobic  (without oxygen) cellular respiration follows a different  and less efficient chemical pathway to provide  energy in cells. Cellular  respiration also releases the energy needed to maintain body temperature despite ongoing  energy loss to the surrounding environment. Matter and energy are conserved  in each change. This is true of all biological  systems, from individual  cells to ecosystems. 12LS1.C

Photosynthesis and cellular respiration (including  anaerobic processes)  provide  most of the energy for life processes. Plants or algae form the lowest level of the food  web. At each link upward in a food  web,
only a small fraction  of the matter  consumed  at the lower level is transferred upward, to produce  growth  and release energy in cellular respiration at the higher level. Given this inefficiency, there are generally fewer organisms  at higher levels of a food  web, and there is a limit to the number  of organisms  that  an ecosystem can sustain.
The chemical elements that  make up the molecules of organisms  pass through food webs and into and out of the atmosphere and soil and are combined and recombined in different  ways. At each link in an ecosystem, matter and energy are conserved;  some matter  reacts to release energy for life functions, some matter  is stored  in newly made structures, and much is discarded. Competition among  species is ultimately  competition for the matter  and energy needed for life.

Photosynthesis and cellular respiration are important components of the car- bon cycle, in which carbon  is exchanged  between the biosphere,  atmosphere, oceans, and geosphere through chemical, physical, geological, and biological processes. 12LS2.B

Common Core Standards

Common Core Standards (i.e. connections with Math, Social Studies or Language Arts Standards):

Math standards can be easily incorporated into this topic. 

Math  9.3.1.5  Make reasonable estimates and judgments about the accuracy of values resulting from calculations involving measurements.

Students may look at energy levels and the percent that is transferred to the next level in a food chain.

Math 9.4.2.3.   Design simple experiments and explain the impact of sampling methods, bias and the phrasing of questions asked during data collection.

This standard can be addressed with all data collection methods.  Statistical analysis and Graphing can be done

Common Core Language Arts:   Students can write a laboratory report in the proper form and using their knowledge of technical writing skills.  Common core standards addressed:

RST.9-10.1. Cite specific textual evidence to support analysis of science and technical texts, attending to the precise details of explanations or descriptions.

RST.9-10.2. Determine the central ideas or conclusions of a text; trace the text's explanation or depiction of a complex process, phenomenon, or concept; provide an accurate summary of the text.

RST.9-10.3. Follow precisely a complex multistep procedure when carrying out experiments, taking measurements, or performing technical tasks, attending to special cases or exceptions defined in the text.