Chapter 1 The Science of Chapter 1 The Science of BiologyBiology

Chapter 1 The Science of Chapter 1 The Science of BiologyBiology

What is Science?What is Science?

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Objectives• What is the goal of science?

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What Science Is and Is Not

• The goal of science1.Investigate and understand the

natural world

2. Explain events in the natural world

3. Use the explanations to make useful predictions

The The Scientific Scientific MethodMethod

A Way to Solve a A Way to Solve a ProblemProblem

The The Scientific Scientific MethodMethod

A Way to Solve a A Way to Solve a ProblemProblem

What is the Scientific Method?

• It is the steps someone takes to identify a question, develop a hypothesis, design and carry out steps or procedures to test the hypothesis, and document observations and findings to share with someone else.

• In other words, it’s a way to solve a problem.

Scientist have to take the time to think logically when they are investigating a question or problem.

• They break things down into many steps that make sense.

Scientists develop a question, gather information and form an hypothesis.

The next step scientists take is to

create and conduct an experiment to test their hypothesis.

A key to experiments is observing what happens and writing it down.

• Gathering information or data and documenting it so it is readable and makes sense to others is really important.

Once a scientist completes an experiment, they often repeat it to see if they get the same findings and results.

• This is really what we call verification, or checking things out to make sure everything was valid and will happen again and again.

Scientists share their experiments and findings with others.

• Because they share their experiments and findings, scientists can learn from each other and often use someone else’s experiences to help them with what they are studying or doing.

The steps of the Scientific Method are:

• Question• Research• Hypothesis• Procedure/Method• Data• Observations• Conclusion

How Science WorksHow Science WorksHow Science WorksHow Science Works

Objectives• How do scientists test hypothesis?

• How does a scientific theory develop?

Testing Hypothesis• Ask a Question• Form a Hypothesis

– Educated guess– Design experiment– Gather data– Conclusion or retest– Ex: Spontaneous Generation – beginning

of experimental science.

Spontaneous Generation

• Idea that life came from nonliving matter• In 1668 Francesco Redi observed maggots

and flies on meat after a few days.– Produced new hypothesis that flies produce

maggots.– Designed experiment – Contained 2 variables

• Manipulated variable – deliberately changed• Responding variable – changes in response to

manipulated variable

Needham’s Test of Redi’s Findings

• Mid-1700’s used van Leevenhoek’s microscope to view small “animalcules”.

• Claimed spontaneous generation could occur under right conditions

• Sealed a bottle of gravy and heated it.– He claimed the heat killed the animalcules

• Several days later he found animalcules in the gravy – concluded spontaneous generation can happen.

Spallanzani’s Test• Thought Needham did not heat the

gravy long enough• Boiled two containers of gravy

1. Sealed one jar immediately2. Second jar left open

• Examined a few days later1. Sealed – No life2. Open – Life came from air

Pasteur’s Test• 1800’s added to Spallanzani’s experiment• Designed a long neck flask which allowed

air in with no microorganisms.• After heating – no life existed• 1 year later – broke the neck and then

microorganisms grew• Final experiment to disprove spontaneous

generation.

If Experiments Not Possible

• Some research has to be conducted in wild– Studying wild animals

• Ethical considerations– Can not conduct experiments on

people unless they volunteer and is not illegal.

Theory Development• A well supported hypothesis that

has been tested numerous times• No theory is absolute truth• It is continually analyzed, reviewed,

and critiqued• With new technology and evidence

it can be revised

Characteristics of Characteristics of Living ThingsLiving Things

Characteristics of Characteristics of Living ThingsLiving Things

Objectives• What are some characteristics of

living things?

Characteristics of Life• Energy Transformation• Organization• Reproduction• Growth• Development• Reaction to Surroundings

– Stimulus and Response– Acclimation– Adaptation

Energy Transformation• Living things take in

energy and change it into different forms.

• The transformed energy is used to power all of life’s processes (growth, etc.)

• Metabolism is the term for all of an organism’s bio-chemical reactions and energy transformations.

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Organization• Living things are

highly organized: they are all composed of tiny living units called cells.

• Some organisms consist of only a single cell (unicellular), others have trillions (multicellular).

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Reproduction• Individual organisms

die, but the species continues because of reproduction.

• Reproduction without genetic contribution from two parents is called asexual.

• Sexual reproduction produces offspring with genetic material from both parents.

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Growth• Living things grow

over their lifetimes. Single- celled organisms increase their volume and multicellular organisms add to the number of cells in their body. Image from

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Development• As an organism matures,

it does not just grow.• Tissues, organs and

organ systems turn on or change their operations, leading to changes in the whole organism.

• Puberty is a period of rapid development in humans.

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Reaction to Surroundings

• Living things react to and interact with their surroundings: the living and non-living factors of the environment.

• These reactions can take place almost instantly or over a period of hours, days, months, years, or even generations.

• The three types of reactions are: respond to stimulus, acclimation, and adaptation.

Respond to Stimulus• When presented

with the proper stimulus, a living organism will respond.

• Not all organisms will respond to the same stimulus in the same way, though.

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Acclimation• Over a relatively short

period of time, organisms can get used to local conditions. This is called acclimation.

• Their body chemistry may change temporarily.

• Humans living at high altitudes for a few months develop more red blood cells than people at sea level.

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Adaptation• Over (generally) long

periods of time (several to thousands generations, depending on the critter), environmental pressures may lead to permanent genetic changes in organisms.

• This process is called adaptation, or evolution.

• These changes, or adaptations, help the organism survive and reproduce in its environment.

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Studying LifeStudying LifeStudying LifeStudying Life

Objective

• How can life be studied at different levels?

Internal Balance• Homeostasis – maintaining

internal processes such as temperatures and water constent– Muscle shivering produces heat– Sweat allows for cooling

Branches of Biology• No one scientist studies everything• Specialize in a level of organization

– Biosphere– Ecosystem– Community– Population– Organism– Groups of cells– Cells– molecules

• Biosphere: The earth and everything on it (living and nonliving), including the atmosphere.

• Ecosystem: All organisms living in a particular area, as well as all the nonliving physical components of the environment that affect the organisms, such as air, soil, and sunlight. (Example: Cascade Mountain rainforest, Kentucky lake and its watershed.)

• Community: The organisms of an ecosystem make up a community.

• Population: The members of a single species in a community make up a population.

• Organism: One member of a species.

• Groups of Cells– Organ systems: A group of organs that

complete a function within the individual. (Example: circulatory system or nervous system.

– Organ: One component of an organ system. (Example: heart, brain)

– Tissues: An organ may be made up of different tissues that perform a function. Tissues are made up of groups of similar cells. (Example: muscle tissue, connective tissue)

• Cell: The smallest “unit of life”. A cell is a membrane bound box that contains molecules in a solution of water.

– Organelles: Subcellular membrane bound compartments that partition special activities. (Example: chloroplasts for photosynthesis)

• Molecules: Combinations of atoms formed in cells and organelles to perform a function such as metabolism or storage of energy.

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