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Chapter 01

Lecture Outline

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Exploring Life and Science

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Points to ponder

• What is biology?

• What characterizes life?

• How do we classify life?

• Where do humans fit into the big picture?

• How do we study science?

• Where is scientific information published and

what should you be aware of?

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What characteristics are shared

by living organisms?

• Organized from the atom to the biosphere

• Use materials and energy from the environment

• Maintain a relatively constant internal

environment (homeostasis)

• Respond to internal and external stimuli

• Reproduce and grow

• Have an evolutionary history through which

organisms change over time

1.1 The Characteristics of Life

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How are living things organized? 1.1 The Characteristics of Life

nervous system shoot system

leaf

photosynthetic tissue

plant cell

brain

nervous tissue

neuron

Biosphere Regions of the Earth’s crust,

waters, and atmosphere inhabited by living things

Ecosystem A community plus the physical environment

Community Interacting populations in a particular area

Population Organisms of the same species

in a particular area

Organism An individual; complex individuals

contain organ systems

Organ System Composed of several organs

working together

Organ Composed of tissues functioning

together for a specific task

Tissue A group of cells with a common

structure and function

Cell The structural and functional

unit of all living things

Molecule Union of two or more atoms

of the same or different elements

Atom Smallest unit of an element composed of

electrons, protons, and neutrons

Figure 1.2 Levels of

biological organization.

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How do we classify humans?

Human House cat

Domain Eukarya Eukarya

Kingdom Animalia Animalia

Phylum Chordata Chordata

Class Mammalia Mammalia

Order Primates Carnivora

Family Hominidae Felidae

Genus Homo Felis

Species sapiens domesticus

1.2 Humans Are Related to Other Animals

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What distinguishes humans?

• Cultural heritage or patterns of our behavior

passed from one generation to the next

• Highly developed brains

• Completely upright stance

• Creative language skills

• Varied tool use

• Modification of our environment for our own

purpose which may threaten the biosphere

1.2 Humans Are Related to Other Animals

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What do we know about science? • Science is a way of knowing about the natural

world.

• Science and scientists should be objective.

• Scientific conclusions may change or be modified as our understanding and technology increase.

• Science is studied using the scientific method.

1.3 Science as a Process

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Scientific theories in biology

1.3 Science as a Process

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The steps of the scientific

method • Start with an observation

• Develop a hypothesis

• Make a prediction and perform

experiments

• Collect and analyze data

• Develop a conclusion

1.3 Science as a Process

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The steps of the scientific method 1.3 Science as a Process

Figure 1.7 The scientific method.

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A controlled study

• Variables

• Experimental variable is the variable that is purposely changed or manipulated.

• All other variables need to remain constant.

• Groups

• Test group is a group of subjects that are exposed to the experimental variable.

• Control group is a group for comparison that is not exposed to the experimental variable.

1.3 Science as a Process

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1.3 Science as a Process

A controlled study in action

Figure 1.9 A controlled

laboratory experiment to

test the effectiveness of a

medication in humans.

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• Observations: Many patients had a particular

bacterium near their ulcers.

• Hypothesis: Helicobacter pylori is the cause of

gastritis and ulcers.

How the cause of ulcers was discovered:

The scientific method in action

1.3 Science as a Process

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• Experiment/observations:

1st – H. pylori was isolated and grown from ulcer

patients.

2nd – Humans swallowing a H. pylori solution

developed inflammation in their stomachs.

• Conclusion: H. pylori was the cause of most

ulcers and can be cured by antibiotics.

How the cause of ulcers was discovered:

The scientific method in action

1.3 Science as a Process

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Reading about scientific information

• Scientific journals are considered the best source of information but can be difficult for the lay person to understand.

• Often the lay person reads secondary sources and must be wary of information taken out of context.

• Be careful of information on the Internet by using reliable sources such as URLs with .edu, .gov and .org.

1.3 Science as a Process

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What should you look for when

you read about science?

• Beware of anecdotal data.

• Understand methodology and results.

• Does the data justify the conclusions inferred by

the scientists?

• Be able to read a graph.

• Have some understanding of statistics.

1.4 Making Sense of a Scientific Study

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Reading a graph What information does this line graph convey?

1.4 Making Sense of a Scientific Study

Figure 1.10 The presentation of scientific data.

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Does science have social

responsibilities?

• Science is a way of acquiring knowledge about

the natural world.

– It is a slightly different endeavor than technology.

1.5 Challenges Facing Science

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Does science have social

responsibilities?

• Technology is the application of scientific

knowledge to human interests.

• Bioethics is the branch of ethics concerned

with the development and consequences of

biological technology.

- Genetic engineering (genetically modified crops)

- Threat to biodiversity

1.5 Challenges Facing Science

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Human Influence on

Ecosystems

• Humans tend to modify ecosystems for their own

purposes.

• Changes in human behavior and use of new

technology can result in new diseases (emerging

diseases).

• Human activities may attribute to climate change

(global warming).

1.5 Challenges Facing Science