Ch2 Sect1 Characteristics of Living Things (Organisms) 1.Cellular Organization - all organisms are made of cells 2.Chemicals of Life 3.Energy Use - cells use energy to perform jobs, such as repair parts and move chemicals around 4.Response to Surroundings 5.Growth and Development 6.Reproduction - Producing offspring that are similar to the parents

1. Cellular Organization - all organisms are made of cells A. Unicellular - an organism made up of only 1 cellA. Unicellular - an organism made up of only 1 cell B. Multicellular - an organism made up of many specialized cells that do certain tasksB. Multicellular - an organism made up of many specialized cells that do certain tasks

2. The chemicals of life All living things are composed of four basic elements:All living things are composed of four basic elements: Carbon (C)Carbon (C) Hydrogen (H)Hydrogen (H) Nitrogen (N)Nitrogen (N) Oxygen (O)Oxygen (O) Other important elements include Iron (Fe), Calcium (Ca), Phosphorous (P), and Sulfur (S).Other important elements include Iron (Fe), Calcium (Ca), Phosphorous (P), and Sulfur (S). Together, these elements make up the main compounds of life: carbohydrates, proteins, lipids and nucleic acids.Together, these elements make up the main compounds of life: carbohydrates, proteins, lipids and nucleic acids.

2. Chemicals of Life A. All cells contain waterA. All cells contain water B. Carbohydrates - cells' main energy sourceB. Carbohydrates - cells' main energy source C. Protein - cells' building materialC. Protein - cells' building material D. Lipids (fats and oils) - energy storage and building materialD. Lipids (fats and oils) - energy storage and building material E. Nucleic Acids - genetic material that direct cellular activities – DNA, RNAE. Nucleic Acids - genetic material that direct cellular activities – DNA, RNA

3. Energy Use (metabolism) - Cells use energy to perform jobs, such as repair parts, move chemicals around and make proteins.

4. Response to Surroundings A. Stimulus - a change in an organism's environmentA. Stimulus - a change in an organism's environment B. Response - an action or change in behavior caused by a stimulusB. Response - an action or change in behavior caused by a stimulus

5. Growth and Development A. Growth - become largerA. Growth - become larger B. Development - process of change to become more complexB. Development - process of change to become more complex

6. Reproduction - Producing offspring that are similar to the parents Asexual - one parent and offspring is identical to that parent.Asexual - one parent and offspring is identical to that parent. Sexual – Usually 2 parents and offspring is a genetic combination of yet different from both parents.Sexual – Usually 2 parents and offspring is a genetic combination of yet different from both parents.

What gives the property of life? Life is more than adding up the elements.Life is more than adding up the elements. These elements interact with each other to cause chemical reactions that are characteristic of life.These elements interact with each other to cause chemical reactions that are characteristic of life.

Life comes from life Living things arise from living things through reproduction.Living things arise from living things through reproduction. The old, mistaken idea, spontaneous generation, was that living things could arise from non-living things = FALSE!The old, mistaken idea, spontaneous generation, was that living things could arise from non-living things = FALSE!

Spontaneous Generation Theory Untill 1600s, most people believed that life came from nonliving matter.Untill 1600s, most people believed that life came from nonliving matter – Francesco Redi – Italian doctor and poet who helped disproved this theory. (p. 36)1668 – Francesco Redi – Italian doctor and poet who helped disproved this theory. (p. 36) One of the first scientists to run a controlled study. Independent variable?One of the first scientists to run a controlled study. Independent variable? Whether or not the jar was covered.Whether or not the jar was covered.

Francesco Redi’s Conclusion: He demonstrated that the presence of maggots in decaying meat does not result from spontaneous generation but from eggs laid on the meat by flies. THEREFORE….He demonstrated that the presence of maggots in decaying meat does not result from spontaneous generation but from eggs laid on the meat by flies. THEREFORE…. Rotting meat does not produce flies!Rotting meat does not produce flies!

Louis Pasteur further disproves spontaneous generation. Pasteur, in the 1800s, conducted more controlled experiments. (p.37)Pasteur, in the 1800s, conducted more controlled experiments. (p.37) He added broth to two flasks, but only sterilized one of them by boiling it. He added curved necks to the flasks so air could get in, but not bacteria.He added broth to two flasks, but only sterilized one of them by boiling it. He added curved necks to the flasks so air could get in, but not bacteria. The one not boiled grew cloudy.The one not boiled grew cloudy. He then broke the neck off the boiled broth and it finally turned cloudy too.He then broke the neck off the boiled broth and it finally turned cloudy too.

Pasteur’s conclusion: New bacteria arise only from existing bacteria.New bacteria arise only from existing bacteria. The experiment of Redi and Pasteur helped to convince people that living things do not arise from nonliving things.The experiment of Redi and Pasteur helped to convince people that living things do not arise from nonliving things.

The Needs of Living Things Water Most organisms can live only for a few days without water.Most organisms can live only for a few days 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 Things Food Provides the source of energy to liveProvides the source of energy to live Autotrophs – make their own food ex. plant using sun’s energy.Autotrophs – make their own food ex. plant using sun’s energy. Heterotrophs – obtain food by feeding on others. (A heterotroph’s energy source is also the sun, but indirectly, how?)Heterotrophs – obtain food by feeding on others. (A heterotroph’s energy source is also the sun, but indirectly, how?)

The Needs of Living Things Living Space All organisms need a space in which to live that provides shelter, food and water.All organisms need a space in which to live that provides shelter, food and water. Space on Earth is limited, so organisms often must compete for space.Space on Earth is limited, so organisms often must compete for space. How does a tree do this?How does a tree do this?

The Needs of Living Things Stable Internal Conditions Organisms must keep internal conditions stable.Organisms must keep internal conditions stable. Homeostasis - maintenance of stable internal conditions. Keeps things just right for cells to function.Homeostasis - maintenance of stable internal conditions. Keeps things just right for cells to function. Why do you get thirsty?Why do you get thirsty? How do barnacles keep water in their cells at low tide?How do barnacles keep water in their cells at low tide?