Ch2 Sect1 Characteristics of Ch2 Sect1 Characteristics of Living Things (Organisms)Living Things (Organisms)

1.1. Cellular Organization - all organisms are Cellular Organization - all organisms are made of cellsmade of cells

2.2. Chemicals of LifeChemicals of Life

3.3. Energy Use - cells use energy to Energy Use - cells use energy to perform jobs, such as repair parts and perform jobs, such as repair parts and move chemicals aroundmove chemicals around

4.4. Response to SurroundingsResponse to Surroundings

5.5. Growth and DevelopmentGrowth and Development

6.6. Reproduction - Producing offspring that Reproduction - Producing offspring that are similar to the parentsare similar to the parents

1. Cellular Organization - all 1. Cellular Organization - all organisms are made of cellsorganisms are made of cells

• A. Unicellular - an organism made up of A. Unicellular - an organism made up of only 1 cellonly 1 cell

• B. Multicellular - an organism made up B. Multicellular - an organism made up of many specialized cells that do certain of many specialized cells that do certain taskstasks

2. The chemicals of life2. The chemicals of life

• All living things are composed of four basic All living things are composed of four basic elements:elements:• Carbon (C)Carbon (C)• Hydrogen (H)Hydrogen (H)• Nitrogen (N)Nitrogen (N)• Oxygen (O)Oxygen (O)

• Other important elements include Iron (Fe), Calcium Other important elements include Iron (Fe), Calcium (Ca), Phosphorous (P), and Sulfur (S).(Ca), Phosphorous (P), and Sulfur (S).

• Together, these elements make up the main Together, these elements make up the main compounds of life: carbohydrates, proteins, compounds of life: carbohydrates, proteins, lipids and nucleic acids.lipids and nucleic acids.

2. Chemicals of Life2. Chemicals of Life

• A. All cells contain waterA. All cells contain water• B. Carbohydrates - cells' main energy B. Carbohydrates - cells' main energy

sourcesource• C. Protein - cells' building materialC. Protein - cells' building material• D. Lipids (fats and oils) - energy storage D. Lipids (fats and oils) - energy storage

and building materialand building material• E. Nucleic Acids - genetic material that E. Nucleic Acids - genetic material that

direct cellular activities – DNA, RNAdirect cellular activities – DNA, RNA

3. Energy Use (metabolism)3. Energy Use (metabolism)

- Cells use energy to perform - Cells use energy to perform jobs, such as repair parts, move jobs, such as repair parts, move chemicals around and make chemicals around and make proteins.proteins.

4. Response to Surroundings4. Response to Surroundings

• A. Stimulus - a change in an organism's A. Stimulus - a change in an organism's environmentenvironment

• B. Response - an action or change in B. Response - an action or change in behavior caused by a stimulusbehavior caused by a stimulus

5. Growth and Development5. Growth and Development

• A. Growth - become largerA. Growth - become larger

• B. Development - process of change to B. Development - process of change to become more complexbecome more complex

6. Reproduction - Producing 6. Reproduction - Producing offspring that are similar to the offspring that are similar to the parentsparents

• Asexual - one parent and offspring is Asexual - one parent and offspring is identical to that parent.identical to that parent.

• Sexual – Usually 2 parents and offspring is Sexual – Usually 2 parents and offspring is a genetic combination of yet different from a genetic combination of yet different from both parents.both parents.

What gives the property of life?What gives the property of life?

• Life is more than adding up the Life is more than adding up the elements.elements.

• These elements interact with each other These elements interact with each other to cause chemical reactions that are to cause chemical reactions that are characteristic of life.characteristic of life.

Life comes from lifeLife comes from life

• Living things arise from living things Living things arise from living things through reproduction.through reproduction.

• The old, mistaken idea, The old, mistaken idea, spontaneous spontaneous generationgeneration, was that living things could , was that living things could arise from non-living things = FALSE!arise from non-living things = FALSE!

Spontaneous Generation TheorySpontaneous Generation Theory

• Untill 1600s, most people believed that Untill 1600s, most people believed that life came from nonliving matter.life came from nonliving matter.

• 1668 – Francesco Redi – Italian doctor 1668 – Francesco Redi – Italian doctor and poet who helped disproved this and poet who helped disproved this theory. (p. 36)theory. (p. 36)

• One of the first scientists to run a One of the first scientists to run a controlled study. Independent variable?controlled study. Independent variable?

• Whether or not the jar was covered.Whether or not the jar was covered.

Francesco Redi’s Conclusion:Francesco Redi’s Conclusion:

• He demonstrated that the presence of He demonstrated that the presence of maggots in decaying meat does not result maggots in decaying meat does not result from spontaneous generation but from eggs from spontaneous generation but from eggs laid on the meat by flies. THEREFORE….laid on the meat by flies. THEREFORE….

• Rotting meat does not produce flies!Rotting meat does not produce flies!

Louis Pasteur further disproves Louis Pasteur further disproves spontaneous generation.spontaneous generation.• Pasteur, in the 1800s, conducted more Pasteur, in the 1800s, conducted more

controlled experiments. (p.37)controlled experiments. (p.37)

• He added broth to two flasks, but only He added broth to two flasks, but only sterilized one of them by boiling it. He added sterilized one of them by boiling it. He added curved necks to the flasks so air could get in, curved necks to the flasks so air could get in, but not bacteria.but not bacteria.

• The one not boiled grew cloudy.The one not boiled grew cloudy.

• He then broke the neck off the boiled broth He then broke the neck off the boiled broth and it finally turned cloudy too.and it finally turned cloudy too.

Pasteur’s conclusion:Pasteur’s conclusion:

• New bacteria arise only from existing New bacteria arise only from existing bacteria.bacteria.

• The experiment of Redi and Pasteur The experiment of Redi and Pasteur helped to convince people that living helped to convince people that living things do not arise from nonliving things do not arise from nonliving things.things.

The Needs of Living ThingsThe Needs of Living Things

WaterWater• Most organisms can live only for a few days Most organisms can live only for a few days

without water.without water.• Needed for chemical reactions and…Needed for chemical reactions and…

• Obtaining chemicals from surroundingsObtaining chemicals from surroundings• Breaking down foodBreaking down food• GrowingGrowing• Moving substances aroundMoving substances around• ReproductionReproduction

The Needs of Living ThingsThe Needs of Living Things

FoodFood• Provides the source of energy to liveProvides the source of energy to live

• Autotrophs – make their own food ex. Autotrophs – make their own food ex. plant using sun’s energy.plant using sun’s energy.

• Heterotrophs – obtain food by feeding on Heterotrophs – obtain food by feeding on others. (A heterotroph’s energy source is others. (A heterotroph’s energy source is also the sun, but indirectly, how?)also the sun, but indirectly, how?)

The Needs of Living ThingsThe Needs of Living Things

Living SpaceLiving Space• All organisms need a space in which to All organisms need a space in which to

live that provides shelter, food and live that provides shelter, food and water.water.

• Space on Earth is limited, so organisms Space on Earth is limited, so organisms often must compete for space.often must compete for space.

• How does a tree do this?How does a tree do this?

The Needs of Living ThingsThe Needs of Living Things

Stable Internal ConditionsStable Internal Conditions• Organisms must keep internal conditions Organisms must keep internal conditions

stable.stable.• Homeostasis Homeostasis - maintenance of stable internal - maintenance of stable internal

conditions. Keeps things just right for cells to conditions. Keeps things just right for cells to function.function.

• Why do you get thirsty? Why do you get thirsty? • How do barnacles keep water in their cells at How do barnacles keep water in their cells at

low tide?low tide?