Chapter 13

The Non-Living Environment

Environmental Factors

• Biotic Factors – Features of the environment that are alive or were

once alive – Biotic means living

• Abiotic Factors– Nonliving physical features of the environment– Abiotic factors include air, water, soil, sunlight,

temperature, and climate– These factors determine which kinds of living

organism can live there

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Abiotic Factors

• Air– Invisible and plentiful– Called the atmosphere– Contains 78% nitrogen, 21% Oxygen, .94%

argon, .03% Carbon Dioxide and trace amounts of other gases

– Plants use CO2 along with H2O and Sunlight in Photosynthesis to make sugar

• Give off Oxygen into the atmosphere

– All organisms carry out respiration in their cells to obtain energy needed for life

– Respiration is a process to release energy stored in the food that we eat

– In respiration cells take in Oxygen from the atmosphere and release Carbon Dioxide

• Water – Essential for life on earth– Major ingredient of the fluid inside the cells of

all organism – Most organisms are composed of 50-95%

water – Many life function need water to take place,

for example, Respiration, digestion, and photosynthesis

• Soil– Mixture of minerals and rock particles, the

remains of dead organisms, water, and air. – Topmost portion of the earths crust– Supports plant growth – Formed from the breaking up of rocks into tiny

particles– Contains many living organisms and the

decaying remains of dead organisms

– Life includes: bacteria, fungi, insects and worms

– Soil contains different combination of sand clay and humus (decaying matter)

– Type of soil presents has an important role of what type and how much plant life is found

Type of Soil Example of Test Jar

Sandy soils are found throughout Southern California, but are very common near the mountain foothills, along rivers and streams and certain coastal areas. Sandy soils are typically comprised of approximately 80 - 100% sand, 0 - 10% silt and 0 - 10% clay by volume. Sandy soils are light and typically very free draining, usually holding water very poorly due to very low organic content.

                                                           

Loam soils are also common in Southern California, particularly in the valleys and flat areas (flood plains) surrounding rivers and streams. Loam soils are typically comprised of approximately 25 - 50% sand, 30 - 50% silt and 10 - 30% clay by volume.  Loam soils are somewhat heavier than sandy soils, but also tend to be fairly free draining, again, due to typically low organic content.

                                                           

Clay soils are very common in certain areas, particularly around urban areas where fill soils have been used to establish grade in subdivisions and developments.  Clay soils are typically comprised of approximately 0 - 45% sand, 0 - 45% silt and 50 - 100% clay by volume.  Clay soils are not typically free draining, and water tends to take a long time to infiltrate. When wet, such soils tend to allow virtually all water to run-off. Clay soils tend to be heavy and difficult to work when dry.

                                                              

 

• Sunlight – Sunlight is the energy for all life– During photosynthesis, producers convert

light energy into chemical energy – Energy from the sun is passed on to

consumers when they eat producers

• Temperature – Sunlight supplies heat energy as well as light

energy– Most organisms can only survive if their body

temperature stays within the range of 0* ans 50* C

– Some organism have adapted to live in climates below and above these temp.

• Pengiuns, and Camels

– Temperature depends on how much direct sunlight an area gets

– Areas located at latitudes farther from the equator tend to have colder temperatures

• Receive less of the suns energy than equatorial areas

• Equator gets direct sunlight• At poles sunlight strikes earth at angles and

energy is spread out over a larger area

– Elevation (distance above sea level) affects temperature

– Higher elevations the atmosphere is thinner, meaning fewer air molecules to be heated by the sun

– Therefore, temperature will be cooler – At higher elevation, trees are shorter and the ground

is rocky– Above timberline (the elevation beyond which trees

do not grow) plant life is limited to low-growing plants – Some mountain tops are covered with snow all year

around

• Climate– Refers to an areas average weather

conditions over time, including temperature, rainfall or other precipitation, and wind

– Temperature and precipitation are the most important components for living things

– Amount of precipitation and average temperature influence the type of life in the area

– Wind • As temperature increase the molecules in the air

spread farther apart, making warm air lighter then cold air

• Cold air sinks below warm air and pushes it upward

• These motions create air currents that are called wind

                        

                                      

– The rain Shadow Effect• Presence of mountains can affect rainfall patterns • As air masses move over a mountain range it

cools • As air cools the moisture at carries falls as rain or

snow • By the time the air mass crosses over the

mountain it has lost all its moisture • This results in the other side of the mountain

getting very little or no precipitation

Cycles in Nature

• Water Cycle– Evaporation- takes place when liquid water

changes into water vapor (gas) and enters the atmosphere

• Water evaporates from lakes, streams, puddles and oceans

• Water vapor enters the atmosphere from plants through a process of transpiration

• Animals release water vapor when they exhale

– Condensation • Water vapor in the atmosphere eventually comes

into contact with cold air • Water vapor cools and changes back into liquid

form (condensation)• Water vapor condenses on particles of dust in the

air, forming tiny droplets– Clump together to form clouds

• Once they become to heavy they fall as precipitation

           

                                                                 

Water Uses

• Homes and Business – 39,100 million gallons/day

• Industry and Mining – 27,800 million gallons/day

• Farms and Ranches- 141,000 million gallons/day

• Electricity Production- 131,800 Million Gallons/day

Nitrogen Cycle

• Nitrogen is the main ingredient of proteins – Proteins are required for life processes

• Nitrogen is the most plentiful gas in our atmosphere but most organism cannot use atmospheric nitrogen

• Plants need nitrogen that is been combined with other elements

• Through a process called Nitrogen Fixation, some bacteria in the soil can form the nitrogen compounds that plants need

• Plants absorb nitrogen through roots• Animals get nitrogen from eating plants

and other animals • When dead organism die they return the

nitrogen back into the soil or atmosphere

• Human activities can affect the nitrogen cycle

• Growing corn and wheat remove much of the nitrogen out of the soil without replacing it

• Farms add fertilizer to the fields to replace the nitrogen taken out

• Compost and animal manure also contain nitrogen compounds

• Another method Farmers use is called Crop Rotation – Farmers grow Nitrogen fixing Crops – Nitrogen fixing bacteria live on or in the roots

of these plants – Farmers will grow corn, wheat or potatoes in a

field for only one-two years and then grow a Nitrogen fixing plants for one-two years

1. Legume symbioses

The most familiar examples of nitrogen-fixing symbioses are the root nodules of legumes (peas, beans, clover, etc.).

                                                                                                                             

                      Part of a clover root system bearing naturally occurring nodules of Rhizobium. Each

nodule is about 2-3 mm long.

                                                                                                                              

                   

                           

   

Carbon Cycle

• Carbon is important part of soil Humus, and is found in the atmosphere as CO2

• Carbon cycle begins when producers remove CO2 to carry out photosynthesis

• CO2 is released by organism in the process of respiration

• Human activities also release CO2 into the environment : Burning Fossil Fuels

• The Amount of CO2 in the Atmosphere is increasing from Tree harvesting, and burning fossil fuels

• Extra CO2 could trap heat and cause average temperatures to increase– Global Warming

• Temperatures are increasing at a rate of about 2* every 10 years

Energy Flow

• Converting Energy– Photosynthesis – Converting solar energy into

chemical energy (Glucose)– Respiration-Converting stored chemical

energy into Kinetic energy (energy to do work)– Chemosynthesis- Organism that use

chemicals to produce energy rich molecules• Bacteria living near hydrothermal Vents deep in

the ocean where there is no light

• Water near hydrothermal vents are very hot because of contact with molten rock

• Waters are rich in chemicals such as sulfur• Consumers living in the vent rely on

chemosynthetic bacteria for nutrients and energy

• Energy Transfer– Energy can be transferred from one organism

to another– Throughout nature energy and matter is

transferred from one organism to another – Food Chains

• Shows how matter an energy passes from one organism to another

• Producers are the first step of the food chain

• Herbivores or Omnivores are the second step• Carnivores or omnivores are the third and higher

steps

• Food Webs – Food webs are made up of many different

food chains – Shows the feeding relationship between all

organism in the community

• Energy Pyramids – The amount of energy available is reduced as

you move from one level to the next– For example: When a plant absorbs sunlight,

it uses some of the energy to grow, therefore when the plant gets eaten not all the energy is passed on

– Animals use energy they obtained to carry out life functions, so when they get eaten less energy is passed on

• The same thing happens at every feeding level of a food chain

• An energy pyramid shows the amount of energy available at each level

• Bottom level is the largest, contains all the producers and contains the most energy

• Only about 10% of the energy available at each level of an energy pyramid is transferred to the next highest level

• Thus 10 percent of the energy in plants becomes stored in the tissues of herbivores, and 10 percent of the energy in herbivores becomes stored in the tissues of carnivores