Biological ThemesBiological Themes

Chapter 1Chapter 1

BiologyBiology

• The study of life.The study of life.

• Includes the study of microscopic Includes the study of microscopic structure of single cells, study of the structure of single cells, study of the global interactions of organisms, & global interactions of organisms, & life history of these organisms. life history of these organisms.

Biological ThemesBiological Themes

• Cell Structure & Cell Structure & FunctionFunction

• Stability & HomeostasisStability & Homeostasis

• Reproduction & Reproduction & InheritanceInheritance

• Evolution Evolution

• Interdependence of Interdependence of OrganismsOrganisms

• Matter, Energy, & Matter, Energy, & OrganizationOrganization

Cell Structure & FunctionCell Structure & Function

• The cell is the basic The cell is the basic unit of life.unit of life.

• Some organisms are Some organisms are – UnicellularUnicellular– MulticellularMulticellular– Differentiation: cells Differentiation: cells

becoming different becoming different from one another as from one another as they multiply.they multiply.

Stability & HomeostasisStability & Homeostasis

• Homeostasis – Stable level of internal Homeostasis – Stable level of internal conditions found in all living things.conditions found in all living things.– Biological balance a cell maintains with Biological balance a cell maintains with

its environment.its environment.

Reproduction & InheritanceReproduction & Inheritance

• Reproduction: the transmission of Reproduction: the transmission of hereditary information from parents hereditary information from parents to offspring.to offspring.– Sexual reproduction: two parents, Sexual reproduction: two parents,

genetic material is combined.genetic material is combined.– Asexual reproduction: one parent, no Asexual reproduction: one parent, no

combining of genetic material.combining of genetic material.

EvolutionEvolution

• Evolution: Change Evolution: Change over a long period over a long period of time.of time.

• Natural SelectionNatural Selection– Survival of the Survival of the

fittest.fittest.

Interdependence of Interdependence of OrganismsOrganisms

• Ecology: Study Ecology: Study of organisms of organisms and with one and with one another and another and their their environment.environment.

• Ecosystems: Ecosystems: Environmental Environmental communities.communities.

Matter, Energy, & Matter, Energy, & OrganizationOrganization• Living things have highly organized Living things have highly organized

structures that must be maintained structures that must be maintained by a constant supply of energy.by a constant supply of energy.– Photosynthesis: Photosynthesis:

•the capture of energy from the sun and the capture of energy from the sun and conversion into food.conversion into food.

– Autotrophs: Autotrophs: •Make their own food, plants.Make their own food, plants.

– Hetertrophs: Hetertrophs: •DonDon’’t make their own food, animals.t make their own food, animals.

Characteristics of LifeCharacteristics of Life

• CellsCells

• OrganizationOrganization

• Energy UseEnergy Use

• HomeostasisHomeostasis

• GrowthGrowth

• ReproductionReproduction

Life ProcessesLife Processes

• Certain activities that make life possible.Certain activities that make life possible.– NutritionNutrition– TransportTransport– Respiration (breakdown of food for energy)Respiration (breakdown of food for energy)– Synthesis & AssimilationSynthesis & Assimilation– Growth & ReproductionGrowth & Reproduction– ExcretionExcretion– Regulation Regulation

Scientific MethodScientific Method

• Observing/Asking a Observing/Asking a QuestionQuestion

• Hypothesizing Hypothesizing • Experimenting Experimenting • Collecting and Collecting and

Analyzing DataAnalyzing Data• Drawing Conclusions/ Drawing Conclusions/

Communicating Communicating ResultsResults

Variables & ControlsVariables & Controls

• Whenever Whenever possible, a possible, a hypothesis should hypothesis should be tested by an be tested by an experiment in experiment in which ONE which ONE variable is variable is changed at a changed at a time.time.

Variables & Controls Variables & Controls cont………cont………• Independent VariableIndependent Variable: :

MANIPULATED; The variable that is MANIPULATED; The variable that is changed.changed.

• Dependent VariableDependent Variable: RESPONDING; : RESPONDING; the variable that changes in response the variable that changes in response to the manipulated variable.to the manipulated variable.

• Controlled VariablesControlled Variables: The variables : The variables that are kept constant.that are kept constant.

Quantitative vs Qualitative

•Quantitative: Numerical value– Quant…quanitity…number

•Qualitative: Value of words

•Examples:– Amount of rainfall in each state in the US

Graphs

•Bar:– Qualitative value and quantitative value

•Line: – Quantitative value and quantitative

value

•Pie:– Percent of a whole

Microscope & MeasurementMicroscope & Measurement• Compound Light Compound Light

MicroscopeMicroscope

• MagnificationMagnification – increase of the increase of the

imageimage’’s apparent s apparent sizesize

• ResolutionResolution – the power to show the power to show

details clearlydetails clearly

Electron MicroscopeElectron Microscope

• A beam of electrons produces an A beam of electrons produces an enlarged image of the specimen.enlarged image of the specimen.– TEM: transmission electron microscopeTEM: transmission electron microscope

•Can view the internal structure of an Can view the internal structure of an organism. organism.

•Magnifies up to 200,000 times.Magnifies up to 200,000 times.

– SEM: scanning electron microscopeSEM: scanning electron microscope•View the surface of an objectView the surface of an object

•Magnifies up to 100,000 times.Magnifies up to 100,000 times.

TEMTEM

Images under TEMImages under TEM

• LungLung Spinach Spinach chloroplastchloroplast

• Rat NerveRat Nerve Mouse kidneyMouse kidney

• Sperm and eggSperm and egg

SEMSEM

Under an SEMUnder an SEM

• PollenPollen LungLung

• Leaf veinLeaf vein Staple through Staple through paperpaper

• Toilet paperToilet paper Hypodermic Hypodermic needleneedle

• Mascara brush with flakes of skin and Mascara brush with flakes of skin and bacteriabacteria

• Sperm and eggSperm and egg

Disadvantages – Electron Disadvantages – Electron MicroscopesMicroscopes

• Very expensiveVery expensive

• Cannot be used to view a living Cannot be used to view a living specimenspecimen

• Can be largeCan be large

Other Lab TechniquesOther Lab Techniques• Cell culture – growth of cells in lab.Cell culture – growth of cells in lab.

• Cell Fractionation – used to release Cell Fractionation – used to release components of cells.components of cells.

• Centrifugation – separation of cell parts by Centrifugation – separation of cell parts by spinningspinning

• Chromatography – separation of Chromatography – separation of components; uses special paper, etc.components; uses special paper, etc.

• Electrophoresis – separation of components Electrophoresis – separation of components based on electrical charge & size.based on electrical charge & size.