Science as a way of learning: A Guide to the Natural World

Science as a way of learning:A Guide to the Natural World

1.1 How Does Science Impact the

Everyday World?

How Does Science Impact theEveryday World?

• Science plays an increasingly important role in the everyday lives of Americans.

• Until the mid-1990s, most Americans did not use e-mail, cell phones, or the Internet.

What Do Americans Know About Science?

Figure 1.1


• The average American has at best an uneven knowledge of science.


• Almost 80 percent of adult Americans who were surveyed know that the continents are moving about the face of the Earth.

• Of those surveyed, 25 percent think the sun goes around the Earth.


Figure 1.3

Early humans did not coexist with dinosaurs.

Antibiotics kill bacteria but not viruses.

The father’s gene determines the sex of a child.

The Earth goes around the sun.

The oxygen we breathe comes from plants.

48%

51%

65%

75%

79%

87%

Percent of Americans who understand that:

Continents are moving on the Earth’s surface.

1.2 What is Science?

What is Science?

• Science is a body of knowledge; a collection of unified insights about nature, the evidence for which is an array of facts.

Science as a Body of Knowledge

• The unified insights of science are known as theories.

• A theory is a general set of principles, supported by evidence, that explains some aspect of nature.


• Science can also be defined as a way of learning; a process of coming to understand the natural world through observation and the testing of hypotheses.


Figure 1.4

Observation

Question

Hypothesis

Experiment

Conclusion


• Science works through the scientific method, in which an observation leads to the formulation of a question about the natural world.


• Science is a tentative, testable explanation that has not been proven true. The hypothesis may be tested through observation or through a series of experiments, as aided by statistical procedures.

Science as Process

• An example of hypothesis testing is Louis Pasteur’s experiment regarding the spontaneous generation of life

When you start with a sterileflask of sterile meat broth. . .

Observation

Question: What is the source of the living material?

Pasteur’s experiments:

Conclusion: No growth appears in the broth unless dust is admitted from outside. Reject “spontaneous generation” hypothesis.

Hypothesis:

. . . a growth of new living materialgenerally appears in the broth.

The living material is derived from nonlivingmaterial (spontaneous generation).

sterile flask

Particletrap

sterilebroth

dust trappedin neck of flask

remove trap

no growth

growth

growth

tip flask to mix trappeddust into broth

Hypothesis 1 Hypothesis 2

The living material is derived fromliving material outside of the flask.

growth ofnew materialin broth

sterile flask

sterile broth

Scientific method at work: Pasteur tests “spontaneous generation”Science as Process

Figure 1.5

Science as Process

• In science, every assertion regarding the natural world is subject to challenge and revision.

When is a Theory Proven?

• Scientific claims must be falsifiable, meaning open to negation through scientific inquiry

• Scientific inquiry is limited to investigating natural (as opposed to supernatural) explanations for natural phenomena.

When is a Theory Proven?PLAYPLAY Animation 1.1 Scientific Method

1.3 The Nature of Biology

The Nature of Biology

• Biology is the study of life.

Characteristics of Living Things

• Life is defined by a group of eight characteristics possessed by living things.


1. Assimilate energy.


2. Respond to their environment.


3. Maintain a relatively constant internal environment.


4. Reproduce.


5. Possess an inherited information base, encoded in DNA, that allows them to function.


6. Are composed of one or more cells.


7. Are evolved from other living things.


8. Are highly organized compared to inanimate objects.

Life is Hierarchical

• Life is organized in a hierarchical manner, ranging in increasing complexity from atoms to molecules to organelles, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystems, and the biosphere.

Life is Hierarchical

Figure 1.6

atom(hydrogen

Molecule(water)

organelle(nucleus)

cell(neuron)

tissue(nervous tissue)

organ(brain)

organ system(nervous system)

organism(sea lion)

population(colony)

community(giant kelp

forest)

ecosystem(southern California

coast)

biosphere(Earth)

1.4 Special Qualities of Biology

Special Qualities of Biology

• Until the early nineteenth century, biology was largely a descriptive science that mainly catalogued and described the Earth’s living things.


• Biology’s subject matter—the living world—is notable for its complexity and diversity compared to other aspects of the natural world (such as stars and atoms).


• Biology does not deal in universal rules to the extent that a discipline such as physics does; instead, biological research may focus on particular species, processes, or portions of the living world.

Biology’s Chief Unifying Principle

• Biology’s chief unifying principle is evolution, which can be defined as the gradual modification of populations of living things over time.

• This modification sometimes results in the development of new species.


• Evolution provides the means for making sense of the forms and processes seen in living things on Earth today.


Figure 1.7


• Many stinging insects with black and yellow stripes look alike because of the general protection this provides from predators


Figure 1.8

Documents

Science as a way of learning: A Guide to the Natural World