1. Distinguish between the biotic community and the abiotic environmental factors of an ecosystem

Biotic community is the grouping of plants, animals, and microbes. Abiotic factors are the humidity, the climate, salinity, or type of soil.

2. Define species, population, association, and ecosystem.

Species: different kinds of plants, animals, and microbes in the community.
•Population: a certain number of individuals that make up the interbreeding, reproducing group.
•Association: plant community with a definite composition, uniform habitat characteristics, and uniform plant growth.
•Ecosystem: a dynamic complex of plant, animal, and microorganism communities and the nonliving environment interacting as a functional unit within an explicit space.

3. Compared with an ecosystem, what are an ecotone, landscape, biome, and biosphere?

Landscape: a group of interacting ecosystems.
•Biomes: Similar ecosystems or landscapes grouped together
•Biosphere: all the ecosystems

4. How do the terms organic and inorganic relate to the biotic and abiotic components of an ecosystem?

Organic refers to all those materials that make up the bodies of living organisms. The key feature of organic materials and molecules is that they are constructed in large part from bonded carbon and hydrogen atoms. Inorganic materials are materials and chemicals in air, water, rocks, and minerals.

5. What are the six key elements in living organisms, and where does each occur - in the atmosphere,

Carbon - All three
•Hydrogen - Atmosphere and Hydrosphere
•Oxygen Atmosphere and Hydrosphere
•Nitrogen - All three
•Phosphorus - Hydrosphere
•Sulfur - Hydrosphere

6. What features distinguish between organic and inorganic molecules?

We distinguish between organic and inorganic according to existence/absence of carbon atoms as an integral part of their molecular structure.

· The structure of organic compounds is based on bounded carbon atoms with hydrogen atoms attached (C-H bound)

· Inorganic compounds / molecules : vice versa

7. define matter and energy, and demonstrate how they are related.

Matter = any gas, liquid, or solid, that occupies space and has a mass (contrast energy)

· Energy = the capacity to do work (no mass, no space)

Common forms of energy are: light, heat, electricity, motion, and the chemical bound energy inherent in compounds such as sugar, gasoline and other fuels.

8. Give four examples of potential energy. In each case, how can the potential energy be converted into kinetic energy?

Potential energy = the ability to work (energy) that is stored in some chemical or physical state. I.e.: gasoline is a form of potential energy because the ability to work is stored in the chemical state and is released as the fuel is burned in an engine.

Examples and means of conversion into kinetic energy:



• explosives - grenade

• firewood - fuel in railway engine

• battery - electric device (depilatory)

• high pressure - hydraulic machine (hydraulic press)

• gasoline - fuel in car



Kinetic energy = weight and movement; the energy inherent in motion or movement, including molecular movement (heat) and movement of waves (hence, radiation and therefore light).

9. State the two energy laws. How do they relate to entropy?

Entropy = degree of disorder, increasing entropy means increasing disorder



· Law of conservation of energy (first law of thermodynamics) = the empirical observation, confirmed innumerable times that energy is never creates or destroyed but may be converted from one form to another (i.e.: electricity to light).

· Second law of thermodynamics = the empirical observation, confirmed innumerable times, that in every energy conversion some of the energy is converted to heat and some heat always escapes from the system because it always moves toward a cooler place. Therefore, in every energy conversion, a portion of energy is lost, and since, by the first law of thermodynamics, energy cannot be created, the functioning of any system requires an energy input.



Conversion of energy to heat and the loss of usable energy to heat are both aspects of increasing entropy! Heat energy is the result of random vibrational motion of atoms and molecules. Heat is the lowest (most disordered) form of energy and its spontaneous flow to cooler place is a way for that disorder to spread.

10. What is the chemical equation for photosynthesis? Examine the origin and destination each molecule referred to in the equation. Do the same for cell respiration.

Photosynthesis (energy-demanding process)



6 CO2 + 12 H2O --------- C6H12O6 + 6 O2 + 6 H2O

(low potential energy) (high potential energy)






There are also mineral nutrients needed (Nitrate, Phosphate, Potassium)



Carbon dioxide is assimilate from atmosphere, water is absorb from soil and light energy becomes from the Sun. Sugar (glucose) can be store (starch, oils), used for tissue growth (biomass production) or consumed during cell respiration (energy release for growth functions)





Cell respiration (energy-releasing process)



C6H12O6 energy+ 6 O2 ------ 6 CO2 + 6 H2O +

(high potential energy) (low potential energy)



Sugar is used as an energy source for growth function and becomes from the photosynthesis. Oxygen is absorbed from the atmosphere and consumed to break down glucose. Carbon dioxide (which is formed as a waste product) moves from the cells into circulatory system) is eliminated through the lungs (or gills) with every exhalation into atmosphere with water vapour.