CellsCellsThe Building The Building Blocks of LifeBlocks of Life

How Did the Earth Form?How Did the Earth Form?

• We do not know for certain how the Earth formed.

• Most scientists agree that the Earth formed about 4.6 billion years ago.

• That is 4,600,000,000 years ago.

Two Theories of How Life on Two Theories of How Life on Earth FormedEarth Formed

• Stanley Miller’s Stanley Miller’s Theory of LifeTheory of Life

• The Volcanic Theory The Volcanic Theory of Lifeof Life

Stanley Miller’s Theory of LifeStanley Miller’s Theory of Life

• This theory states that a mixture of gases and water was struck by lightning and formed a “tar-like” substance that allowed living things to develop.

• Also known as “Primordial Soup”

The Volcanic Theory of LifeThe Volcanic Theory of Life

• The Volcanic Theory of Life states that the cooling planet had lots of volcanoes putting gases into the air.

• These gases condensed into rain that formed oceans.

• Single cell organisms evolved into plant life then animal life.

How did Cells Form?How did Cells Form?

• Several Theories of How Cells Formed:– Cells arose in shallow pools containing “soup”

of chemicals. These chemicals become combined and formed cells.

– Cells formed in beds of clay that allowed substances (chemicals) to be contained and produce living things – cells.

– Meteors and asteroids carried water, containing life (cells) to the Earth.

Which Cell Theory Is True?Which Cell Theory Is True?

• We still do not know for sure how cells formed.

Spontaneous Generation?Spontaneous Generation?

• The Theory of The Theory of Spontaneous GenerationSpontaneous Generation states that life could arise from non-living states that life could arise from non-living matter.matter.

– This theory was disproved in 1668 by This theory was disproved in 1668 by Francesco Redi who used raw meat for his Francesco Redi who used raw meat for his experiments.experiments.

Francesco RediFrancesco Redi

Redi’s ExperimentRedi’s Experiment

Producers and ConsumersProducers and Consumers

• A producer is any organism that makes it’s own food.

– Example: green plants

• A consumer is any organism that can not produce it’s own food.– Consumers are

dependent on other organisms to survive.

– Example: Man

How Do Producers Make Food?How Do Producers Make Food?

• PhotosynthesisPhotosynthesis: the process by which green plants convert sunlight into food.– As a waste product, oxygen is released.

– At some point in history, early cells evolved and became able to perform photosynthesis.

• This is important because this allowed an oxygen atmosphere to form and eventually allows for animal life to evolve.

Characteristics of Living ThingsCharacteristics of Living Things

• All living things share characteristics, they:– Are made of cells– Are able to move– Perform complex chemical activities– Are able to grow and develop– Are able to respond to their environment– Are able to reproduce

What is a Cell?What is a Cell?

• The cell is the basic building block of The cell is the basic building block of all living things.all living things.

– The first cells on Earth are thought to have The first cells on Earth are thought to have evolved ~3.5 billion years ago.evolved ~3.5 billion years ago.

– These cells could not produce their own These cells could not produce their own food.food.

All living things are made of cellsAll living things are made of cells

Plant Cells Animal Cells

What are the Needs of Living What are the Needs of Living Things?Things?

• In order to survive all living things need:– Energy– Food– Water– Oxygen– Living space– To maintain a proper temperature

Cell TheoryCell Theory• The current cell theory

states that:

– All living things are made of cells.

– Cells are the basic unit of structure and function in living things.

– Living cells only come from other living cells.

What Are Cells Made Of?What Are Cells Made Of?

• OrganellesOrganelles, or “tiny organs”, are , or “tiny organs”, are the structures that make up a cell.the structures that make up a cell.

• OrganellesOrganelles were discovered by were discovered by Robert Hooke in 1665 while looking Robert Hooke in 1665 while looking at cork cells.at cork cells.

How Do Cells Function?How Do Cells Function?

• Each of the organelles in a cell has a defined function.

• There are many organelles that make up a cell.– These include the cell wall, cell membrane,

nucleus, cytoplasm, endoplasmic reticulum, ribosomes, lysosomes, mitochondria, vacuoles, chloroplasts.

• All organelles working together create the cells structure.

All living things are able to moveAll living things are able to move

All living things perform All living things perform complex chemical activitiescomplex chemical activities“building up and breaking “building up and breaking

down”down”

• MetabolismMetabolism is the sum total of all the chemical reactions that occur in a living thing.– In humans these chemical reactions are

ingestion, digestion, respiration, and excretion.

IngestionIngestion

• Ingestion is taking in food to processIngestion is taking in food to process..

DigestionDigestion

• Digestion is the process of breaking down food into simpler substances.

RespirationRespiration

• RespirationRespiration is the process of taking in oxygen and using it to produce energy.

ExcretionExcretion

• ExcretionExcretion is the process of getting rid of waste material.

All living things are able to grow All living things are able to grow and developand develop

• Life span is the maximum length of time that an organism is expected to live.

All living things are able to All living things are able to respond to their environmentrespond to their environment

• A stimulusstimulus is something that comes from outside the organism or from within the organism that triggers a reaction.Examples:

cold breezecold breeze

stomach growlstomach growl

• A responseresponse is the reaction that occurs as a result of the stimulus.

Examples:

goose bumpsgoose bumps

eat foodeat food

All living things are able to All living things are able to reproducereproduce

“Like produces like”“Like produces like”• Sexual reproduction:

– Requires two parents– Results in offspring that

show variations

• Asexual reproduction:– Requires one parent– Results in identical

offspring with no variations

Both forms of reproduction give a chemical “blueprintblueprint” to the next generation.

Cellular ReproductionCellular Reproduction

Egg and Sperm Cells - Egg and Sperm Cells - FertilizationFertilization

Meiosis - Sexual ReproductionMeiosis - Sexual ReproductionResult is daughter cells with half the chromosomesResult is daughter cells with half the chromosomes

Mitosis – Asexual ReproductionMitosis – Asexual ReproductionResult is two identical cellsResult is two identical cells

What is Competition?What is Competition?

• Competition is the struggle among living things to get the proper amounts of food, water, oxygen and space.

• Competition plays an important role in shaping a community.

How Do Living Things Maintain How Do Living Things Maintain Proper TemperatureProper Temperature

• HomeostasisHomeostasis is the ability of an organism to is the ability of an organism to keep the conditions inside the body the same keep the conditions inside the body the same even though external environmental even though external environmental conditions change.conditions change.

• Warm bloodedWarm blooded animals maintain a constant animals maintain a constant body temperature at all times.body temperature at all times.– Examples are man and mammalsExamples are man and mammals

• Cold bloodedCold blooded animals have body animals have body temperatures that change with the temperatures that change with the environment.environment.– Examples are fish and reptilesExamples are fish and reptiles

What Makes Up All Living Things?What Makes Up All Living Things?“The Chemistry Of Life”“The Chemistry Of Life”

• All living things are made of elements and compounds.

What is an What is an ElementElement??

• An element is a pure substance that can not be broken down into any simpler substances.– Only 90 natural elements exist on earth.– Only 11 elements are common in living things.– 4 elements (carbon, nitrogen, oxygen and

hydrogen) make up 96% of the weight of the human body.

What is a What is a CompoundCompound??

• A compound is formed when 2 or more elements join together chemically.– Examples are: water H2O, and sugar C6H12O6

A water molecule is an example of a compound

There are 2 Types of CompoundsThere are 2 Types of Compounds

• Inorganic Compounds: are compounds that do not contain carbon. (carbon dioxide, CO2, is an exception)– Examples: salt NaCl, Ammonia NH3, Rust Fe3O2

• Organic Compounds: are compounds that do contain carbon; many are basic to life.– There are many types of organic compounds

including: carbohydrates, fats, oils, proteins, enzymes, and nucleic acids.

Organic Compounds - Organic Compounds - CarbohydratesCarbohydrates

• CarbohydratesCarbohydrates are the main source of energy for living things.– Examples are sugar, starch (fruits, vegetables)– Carbohydrates are made of carbon, hydrogen

and oxygen.

CarbohydratesCarbohydrates

Organic Compounds – Organic Compounds – Fats and OilsFats and Oils

• Fats and oilsFats and oils: known as “lipids” are energy rich compounds. – At room temperature fatsfats are solidsolid and oilsoils

are liquidliquid.– Fats and oils are made of carbon, hydrogen

and oxygen.

Fats and OilsFats and Oils

Organic Compounds - Organic Compounds - ProteinsProteins

• ProteinsProteins are necessary for growth and repair of the body.

• In addition to carbon, hydrogen and oxygen, proteins are also made of nitrogen (sometimes made of sulfur and phosphorous).– Amino acids are the building blocks of

proteins.

ProteinsProteins

Organic Compounds - Organic Compounds - EnzymesEnzymes

• EnzymesEnzymes are special proteins that regulate chemical activities in the body.

• EnzymesEnzymes act as catalystscatalysts.– A catalystcatalyst is a substance that speeds up or

slows down a chemical reaction.

EnzymesEnzymes

Organic Compounds – Organic Compounds – Nucleic AcidsNucleic Acids

• Nucleic acidsNucleic acids are the “blue prints” of life.

• They are large compounds that store information that helps the body make the proteins it needs.– Example: DNA or deoxyribonucleic acid

Nucleic AcidsNucleic Acids

What Is Cell Specialization?What Is Cell Specialization?

• In multicellular organisms, cells not In multicellular organisms, cells not only complete its own life activities, but only complete its own life activities, but also performs a function that also performs a function that contributes to the life of the organism.contributes to the life of the organism.

• Within multicellular organisms there is Within multicellular organisms there is division of labor or specialization.division of labor or specialization.– The work of keeping the organism alive is The work of keeping the organism alive is

divided up among different parts of the divided up among different parts of the organism.organism.

Levels of SpecializationLevels of Specialization

Cells combine to form

Tissues combine to form

Organs combine to form

Organ systems combine to form

Organism

More SpecializationMore Specialization

StudentsStudents combine to form combine to form

ClassesClasses combine to form combine to form

GradesGrades combine to form combine to form

SchoolsSchools combine to form combine to form

DistrictDistrict

What are What are TissuesTissues??

• TissuesTissues are cells that are similar in structure and function that combine together.– Example: bone cells form bone tissue– Other examples: muscle tissue, nerve tissue,

connective tissue.

Bone Tissue and Muscle TissueBone Tissue and Muscle Tissue

What are Organs?What are Organs?

• OrgansOrgans are groups of different tissues are groups of different tissues that work together.that work together.– Example: the heart is an organ made of Example: the heart is an organ made of

muscle tissues and blood tissuemuscle tissues and blood tissue– Other organs: brain, stomach, skinOther organs: brain, stomach, skin

Organs – Heart and StomachOrgans – Heart and Stomach

What are Organ Systems?What are Organ Systems?

• Organ systemsOrgan systems are a group of organs working together to perform a specific function for the organism.– Examples: skeletal system, muscular system,

digestive system.

Organ SystemsOrgan Systems

What are Organisms?What are Organisms?

• OrganismsOrganisms are an entire living thing that carries out all the basic life functions.– Examples: Humans, cat, fish, fly

Some OrganismsSome Organisms