The Nature of BiologyThe Nature of Biology

Module 1: How to Define LifeModule 1: How to Define Life

How do you design an experiment?How do you design an experiment?

A.A. Problem/PurposeProblem/Purpose1.1. The The questionquestion the lab will answer the lab will answer

2.2. Identifies the Identifies the independentindependent and and dependentdependent variablesvariablesa.a. Independent variable – Independent variable – the factor the scientist changes the factor the scientist changes

from group to groupfrom group to group

b.b. Dependent variable – Dependent variable – the factor the scientist measures the factor the scientist measures to see the effect of the independent variableto see the effect of the independent variable

Variables and Controls Videoclip

How do you design an experiment?How do you design an experiment?B.B. Research/Background Research/Background

InformationInformation1.1. Lets the reader Lets the reader learnlearn about the about the

topictopic

2.2. Helps the scientist Helps the scientist developdevelop an an educated hypothesiseducated hypothesis

C. HypothesisC. Hypothesis1.1. An educated predictionAn educated prediction

2.2. Can be Can be testedtested, proven false, and , proven false, and agrees with previous researchagrees with previous research

How do you design an experiment? How do you design an experiment?

D. Procedure/ExperimentD. Procedure/Experiment1.1. Steps must be Steps must be precise and detailedprecise and detailed

2.2. Has one Has one controlcontrol group groupa.a. Normal conditionsNormal conditions or absence of independent variable or absence of independent variable

b.b. Used for comparisonUsed for comparison

3.3. Experimental group(s) have only Experimental group(s) have only oneone changing changing variable (which is the independent variable)variable (which is the independent variable)

How do you design an experiment?How do you design an experiment?

E. Observations/DataE. Observations/Data1.1. Must be Must be objectiveobjective. .

a.a. Good Example: Good Example: The bacterial colony is yellow.The bacterial colony is yellow.

b.b. Bad Example: The bacterial colony is nasty.Bad Example: The bacterial colony is nasty.

2.2. Use Use measurementsmeasurements whenever possible. whenever possible.

a.a. Good Example: Good Example: There are 50 bacterial colonies.There are 50 bacterial colonies.

b.b. Bad Example: There are a whole bunch of colonies.Bad Example: There are a whole bunch of colonies.

How do you design an experiment?How do you design an experiment?

E. Observations/DataE. Observations/Data4.4. Do not draw conclusions Do not draw conclusions in the data section of in the data section of

the report.the report.a.a. Good Example: Good Example: There are bacteria and fungal colonies There are bacteria and fungal colonies

in the shoe section.in the shoe section.

b.b. Bad Example: The shoe was really dirty and so it was Bad Example: The shoe was really dirty and so it was the most contaminated and grew a lot of stuff.the most contaminated and grew a lot of stuff.

5.5. Should be Should be organizedorganized..a.a. May use a May use a graph, tablegraph, table, or drawing(s)., or drawing(s).

b.b. Always include Always include units of measurementunits of measurement and a title. and a title.

How do you design an experiment?How do you design an experiment?

F. Analysis/ConclusionsF. Analysis/Conclusions1.1. Answers Answers the purpose the purpose

question.question.

2.2. Accepts or rejectsAccepts or rejects the the hypothesis.hypothesis.

3.3. Explains what can be Explains what can be inferredinferred from the data. from the data.

How do we know it is “good science”?How do we know it is “good science”?

A.A. Scientific knowledge must be Scientific knowledge must be shared,shared, which allows other scientists to which allows other scientists to repeat and repeat and verifyverify the work of others (peer review). the work of others (peer review).

A. Scientific knowledge is A. Scientific knowledge is tentativetentative..1.1. TheoriesTheories are the most logical explanation based on are the most logical explanation based on

currentcurrent evidenceevidence, become stronger as more , become stronger as more evidence is gathered, and give us a basis for evidence is gathered, and give us a basis for prediction.prediction.

2.2. LawsLaws are universal generalizations that are are universal generalizations that are virtually virtually unchangingunchanging. .

How do you know something is alive?How do you know something is alive? A. Biology means the study of (-ology) all A. Biology means the study of (-ology) all

lifelife (bio-) and includes many branches. (bio-) and includes many branches. B. Biologists organize living things into B. Biologists organize living things into

kingdomskingdoms. There are currently six . There are currently six kingdoms kingdoms

Kingdom Example

Archaebacteria Extremophile bacteria

Eubacteria Typical bacteria

Protista Seaweed, Amoeba, Slime Mold

Fungi Yeast, Mushrooms

Plantae Moss, Fern, Holly, Oak tree

Animalia , Fish, Birds, Frogs, Humans

How do you know something is alive?How do you know something is alive?B.B. Characteristics of Life - Characteristics of Life - Alive! Videoclip

1. 1. OrganizationOrganization (The level of complexity) (The level of complexity)

a.a.

Organism

Organ System

Organs

Tissues

Cells

Molecules

Atoms / Elements

Meet the Elements - They Might Be Giants

How do you know something is alive?How do you know something is alive?

b.b. All living things All living things need six essential need six essential elements (atoms): elements (atoms): Carbon, Hydrogen, Carbon, Hydrogen, Nitrogen, Oxygen, Nitrogen, Oxygen, Phosphorus, Phosphorus, SulfurSulfur (CHNOPS) (CHNOPS)

c.c. All living things All living things are made of are made of cells. cells.

b.b. One-celled One-celled organism – organism – unicellularunicellular

c.c. Many-celled Many-celled organism - organism - multicellularmulticellular

electron

neutron

proton

How do you know something is alive?How do you know something is alive?

2. Energy Use 2. Energy Use a.a. Organisms need energy Organisms need energy

constantly to constantly to buildbuild molecules molecules ((synthesissynthesis) and cells and to ) and cells and to break break downdown (digest) substances (such (digest) substances (such as breaking down food for as breaking down food for nutrition)nutrition)

b.b. Organisms must Organisms must transport transport nutrients to be used in cellular nutrients to be used in cellular respiration to produce energyrespiration to produce energy..

c.c. An organisms’ chemical reactions An organisms’ chemical reactions are called its are called its metabolismmetabolism

How do you know something is alive?How do you know something is alive?

3. Reproduction3. Reproductiona.a. Organisms must Organisms must

replace themselves replace themselves so the entire species so the entire species will survive.will survive.

b.b. May be May be asexualasexual (only one individual (only one individual contributes genetic contributes genetic material) or material) or sexualsexual (two individuals (two individuals contribute genes).contribute genes).

How do you know something is alive?How do you know something is alive? 4. Growth and Development4. Growth and Development

a.a. Growth – to Growth – to increase in sizeincrease in size. Increases . Increases the number of the number of cellscells of a multicellular organism. of a multicellular organism.

b.b. Development – Development – changechange that takes place that takes place in structure in structure and functionand function of an organism during its life cycle. of an organism during its life cycle.

Example: Embryo becomes a fetusExample: Embryo becomes a fetus

How do you know something is alive?How do you know something is alive?

5. Respond to Stimuli5. Respond to Stimulia.a. A A quick, non-quick, non-

permanentpermanent change change

b.b. Stimulus – any Stimulus – any condition that causes condition that causes an organism to an organism to react.react.

Example – A loud noise (stimulus) Example – A loud noise (stimulus) causes your dog to run under causes your dog to run under the bed (response).the bed (response).

How do you know something is alive?How do you know something is alive?

6.6. Adjust to Adjust to EnvironmentEnvironment

a.Homeostasis - the a.Homeostasis - the regulation of an regulation of an organism’s organism’s

internal internal environmentenvironment to to maintain conditions maintain conditions suitable for lifesuitable for life

Ex: Getting rid of Ex: Getting rid of wastes by wastes by excretionexcretion

How do you know something is alive?How do you know something is alive?

b. An b. An adaptationadaptation is an is an inherited inherited structure, structure, behavior, or internal behavior, or internal processprocess that enables that enables organisms to better organisms to better survive an survive an environment.environment.

Ex: Gills on a fishEx: Gills on a fish

Life Processes: STERNGRRLife Processes: STERNGRR Synthesis – making materials Synthesis – making materials Transport – moving materialsTransport – moving materials Excretion – getting rid of wastes Excretion – getting rid of wastes Respiration – gas exchange AND production of Respiration – gas exchange AND production of

energy (ATP)energy (ATP) Nutrition – gaining and using energy from foodNutrition – gaining and using energy from food Growth and Development – getting bigger and/or Growth and Development – getting bigger and/or

changingchanging Regulation – controlling internal processesRegulation – controlling internal processes Reproduction – producing new cells or new Reproduction – producing new cells or new

organismsorganisms

What technology allows biologists What technology allows biologists to study microscopic life?to study microscopic life?

A. Compound Light A. Compound Light MicroscopeMicroscope

1.1. Has two lenses – Has two lenses – ocularocular (eyepiece) (eyepiece) and objectiveand objective

2.2. In order to be viewed, In order to be viewed, specimen must be specimen must be thinthin (so the light may (so the light may shine through the shine through the specimen) and specimen) and placed on a placed on a slideslide..

3.3. Specimen may be Specimen may be stainedstained to better see to better see structures structures

What technology allows biologists to What technology allows biologists to study microscopic life?study microscopic life?

B. Electron MicroscopeB. Electron Microscope1.1. Uses Uses electronselectrons to produce an image to produce an image

2.2. Types:Types:a.a. Scanning Electron Microscope (Scanning Electron Microscope (SEMSEM))

i.i. Sends a beam of electrons Sends a beam of electrons across the object’s across the object’s surfacesurface

ii.ii. Produces a Produces a 3-D3-D image image

b.b. Transmission Electron Microscope Transmission Electron Microscope ((TEMTEM))

i.i. Designed to look at structures Designed to look at structures insideinside a cell a cell

ii.ii. Capable of Capable of greatest greatest magnificationmagnification

Eye of an ant

What technology allows biologists to What technology allows biologists to study microscopic life?study microscopic life?

C. Limitations of microscopesC. Limitations of microscopes1.1. Magnification is limited by the strength of the Magnification is limited by the strength of the

lens.lens.a.a. Calculating magnification:Calculating magnification:

Ocular lens x objective lens = total magnificationOcular lens x objective lens = total magnification

b.b. Example:Example:

Ocular (10x) x objective (40x) = 400x Ocular (10x) x objective (40x) = 400x

2.2. As magnification increases As magnification increases resolution/(resolution/(sharpness) decreases.sharpness) decreases.