The Study of LifeThe Study of Life

1.1 Introduction to Biology1.1 Introduction to Biology

1.2 The Nature of Science 1.2 The Nature of Science

1.3 Methods of Science 1.3 Methods of Science

What is Biology?What is Biology?

Biology: the science of lifeBiology: the science of life BiologistsBiologists

– Study the diversity of lifeStudy the diversity of life– Research diseasesResearch diseases– Develop technologies Develop technologies – Improve agricultureImprove agriculture– Preserve the environment Preserve the environment

All Living Things….All Living Things….

Are made of one or more cellsAre made of one or more cells Are organizedAre organized Grow and developGrow and develop ReproduceReproduce Respond to stimuliRespond to stimuli Require energyRequire energy Maintain homeostasis Maintain homeostasis Evolve over time Evolve over time

Levels of Organization in Living ThingsLevels of Organization in Living ThingsMoleculesMolecules

↓↓CellsCells

↓↓TissuesTissues

↓↓OrgansOrgans

↓↓SystemsSystems

↓↓OrganismsOrganisms

↓↓Populations (members of the same species)Populations (members of the same species)

↓↓Communities (members of several species)Communities (members of several species)

↓↓Ecosystems (living and non-living elements)Ecosystems (living and non-living elements)

↓↓BiosphereBiosphere

What is Science? What is Science? Science: the body of knowledge based on Science: the body of knowledge based on

the study of nature (biology, chemistry, the study of nature (biology, chemistry, physics, Earth science) physics, Earth science)

How is science different than your other How is science different than your other classes? In science class we will:classes? In science class we will:– Relies on evidence Relies on evidence – Explain scientific knowledge Explain scientific knowledge – Challenge accepted theoriesChallenge accepted theories– Question results Question results – Test ClaimsTest Claims– Use peer reviewUse peer review– Use the metric system Use the metric system

Comprehension Check• What is the difference between an

inference and an observation?• Why should scientists be

observant, curious, skeptical, and open-minded?

How does science work?How does science work? Science follows a process (sometimes called the Science follows a process (sometimes called the

scientific method):scientific method):1.1. Ask a QuestionAsk a Question

– Observations: collected with your senses Observations: collected with your senses – Inferences: made with your mindInferences: made with your mind– http://www.youtube.com/watch?v=A3l-0sAiMVA

2.2. Form a hypothesisForm a hypothesis– A testable explanation of a situation A testable explanation of a situation

3.3. Collect Data Collect Data – Controlled Experiments have control and experimental Controlled Experiments have control and experimental

groupsgroups– IndependentIndependent– Dependent Variables Dependent Variables – ConstantsConstants– Data: Quantitative (numbers) and Qualitative (descriptions)Data: Quantitative (numbers) and Qualitative (descriptions)

4.4. Analyze DataAnalyze Data– Graphs and ChartsGraphs and Charts

5.5. Report ConclusionsReport Conclusions

Comprehension CheckIdentify if the following are qualitative

or quantitative data: • The beans were light green in color• The ostrich gained 4.3 grams over a

period of 6 weeks• The beaker contained 300 mL of

red liquid

Making a Valid HypothesisMaking a Valid Hypothesis

Must make a predictionMust make a prediction Must be stated in the “If … then…” Must be stated in the “If … then…”

formatformat Must be testableMust be testable

Experimental Design BA fish was taken from one fish tank with a population of

sixty fish to another fish tank with a population of six fish. The fish’s rate of breathing decreased. What was the most probable cause for this decrease?

a. The population density did not change. b. The temperature in the tank increased. c. The concentration of oxygen in the tank decreased. d. The concentration of carbon dioxide in the tank

decreased.

Experimental Design BA fish was taken from one fish tank with a population of

sixty fish to another fish tank with a population of six fish. The fish’s rate of breathing decreased. What was the most probable cause for this decrease?

a. The population density did not change. b. The temperature in the tank increased. c. The concentration of oxygen in the tank decreased. d. The concentration of carbon dioxide in the tank

decreased.

Tools of the BiologistTools of the Biologist

Scientists use the Metric System of Measurement Scientists use the Metric System of Measurement (S.I.)(S.I.)– based on multiples of 10based on multiples of 10– Scientific data are recorded in tables and Scientific data are recorded in tables and

graphsgraphs

– Examples of metric units:Examples of metric units:

Experimental Design A A scientist has planned an experiment where the growth of mice populations in four aquariums is observed. Each aquarium will initially contain 10 mice and will receive the following food regimens: Aquarium 1: 5 grams food pellets/dayAquarium 2: 7 grams food pellets/dayAquarium 3: 10 grams food pellets/dayAquarium 4: 15 grams food pellets/day

What is the scientists most likely studying in this experiment? a. The effect of habitat size on mice population growthb. The effect of available food resources on mice population growth c. How resource availability changes in a given environment d. The effect of mice population on hawk population

Experimental Design AA scientist has planned an experiment where the growth of mice populations in four aquariums is observed. Each aquarium will initially contain 10 mice and will receive the following food regimens: Aquarium 1: 5 grams food pellets/dayAquarium 2: 7 grams food pellets/dayAquarium 3: 10 grams food pellets/dayAquarium 4: 15 grams food pellets/day

What is the scientists most likely studying in this experiment? a. The effect of habitat size on mice population growthb. The effect of available food resources on mice population growth c. How resource availability changes in a given environment d. The effect of mice population on hawk population

Microscope BasicsMicroscope Basics

1. Compound Light Microscope:•uses light reflected by two or more lenses•We have many of these in the room•Used to see Living objects•Special Type of Scope: Stereoscope

2. Electron Microscope•Uses Uses electronselectrons reflected by magnets. reflected by magnets. •Can be used only with dead or non-living Can be used only with dead or non-living specimensspecimens•These are very large, about the size of the These are very large, about the size of the teacher desk up to the size of a whole roomteacher desk up to the size of a whole room

Scope VocabularyScope Vocabulary Field of viewField of view

– What you see when What you see when looking in the eyepiecelooking in the eyepiece

– Gets smaller when you Gets smaller when you increase magnificationincrease magnification

Working DistanceWorking Distance– Distance between Distance between

objectives and stageobjectives and stage– Gets smaller when you Gets smaller when you

use the high power use the high power objectivesobjectives

Depth-of-fieldDepth-of-field– Occurs when you are Occurs when you are

looking closely at the looking closely at the layers of a specimen, layers of a specimen, you can actually see you can actually see different layers at the different layers at the same time!same time!

Compound Light Microscopes Compound Light Microscopes versus Stereoscopesversus Stereoscopes

•Eyepieces (2 vs 1):

•2 eyepieces allow for a 3-D image

•Lights (2 vs 1):

•2 lights allow you to see solid objects

• Size of Object:

•Larger working distances allows you to see bigger things

The Martian and the Car

Marty Martian was sent to Earth by the Martian government to find life. While on Earth, Marty captured a car and brought it back to Mars. He thought he'd found a good example of life on Earth. The Martian government does not believe that the car Marty brought back is alive. Marty must stand trial for failing to perform his Martian duties.

At the trail, Marty spoke in his defense. "I first saw these life forms rolling along roads in great numbers. They were giving off thick clouds of poisonous waste as they moved. They seemed to exhibit herding behavior, as many of the cars moved in the same direction. They appeared to have a great deal of energy, some of them moved faster than 60 kilometers per hour. When one of these life forms stopped or slow down, the others behind it responded. They slowed down and gave off a reddish light from the back, and sometimes they would make honking noises. I observed that they would stop to feed on a liquid substance."

Take the part of Marty's defense attorney and make a good case for the car's being alive. Then be the prosecutor and show that the car is a nonliving thing.

Defense Attorney Prosecutor1. ___________________________________ 1. _________________________________2. ___________________________________ 2. _________________________________3. ___________________________________ 3. _________________________________4. ___________________________________ 4. _________________________________5. ___________________________________ 5. _________________________________