CHAPTER 1CHAPTER 1

Introduction: Biology Today

• Biology is the scientific study of life.

The Scope of Life

• size scale ranging from the molecular to the global

How do we know what is living?

There are SEVEN characteristics all living things must ALL have:

Seven Characteristics of Life

Order: must be organized, certain parts do certain things, cells

Regulation: maintain stable internal conditions; homeostasis

Growth and Development: get larger and change

Energy Utilization: Take energy in and use it; ‘eat’

Response to the Environment: Stimuli

Reproduction: Make more of same kind

Evolution: Be the best at what it does

Figure 1.2

Example: Dog

Order: has muscle cells that allow it to move

Regulation: When it is thirsty it drinks

Example: Dog

Growth and Development: Gets larger and changes from a puppy to an adult dog

Energy Utilization: eats then plays

Example: Dog

Responds to the environment: Hides for a thunderstorm, moves into shade when hot

Reproduction: PUPPIES

Evolution:

Example: Calculator

Example: Calculator

Order: add button does a different thing than the subtract

Regulation: does not maintain stable conditions

Growth and Development: does not grow or change

Energy Utilization: Does take in light energy and use it to calculate

Response to the Environment: doesn’t respond

Reproduction: does not have sex and make baby calculators, nor does it divide into two new calculators

Evolution: has changed over time but not without human help.

• Biologists explore life at levels ranging from the biosphere to the molecules that make up cells.

Life at Its Many Levels

Cells

• The cell is the smallest level of structure that can perform all activities required for life.

– All organisms are composed of cells.

• We can distinguish two major types of cells:

– Prokaryotic

– Eukaryotic

• The prokaryotic cell is simple, small, and contains no organelles.

• The eukaryotic cell is larger and more complex and contains organelles.

Figure 1.5

Life in Its Diverse Forms

• Diversity is the hallmark of life.

– The diversity of known life includes 1.8 million species.

– Estimates of the total diversity range from 10 million to over 200 million species.

• Taxonomy is the branch of biology that helps categorize this diversity

The Three Domains of Life

• The three domains of life are:

– Bacteria

– Archaea

– Eukarya

• Bacteria and Archaea are both prokaryotic domains.

• Eukarya includes at least four kingdoms:

– Plantae

– Fungi

– Animalia

– Protists (multiple kingdoms)

The Process of Science

• The word science is derived from a Latin verb meaning “to know.”

– Science is a way of knowing.

– Science developed from people’s curiosity about themselves and the world around them.

Figure 1.17

Hypothesis-Driven Science

• As a formal process of inquiry, the scientific method consists of a series of steps.

– The key element of the scientific method is hypothesis-driven science.

Figure 1.18

• A hypothesis is a tentative answer to some question.

– It is an explanation on trial.

Figure 1.19

The Process of Science: Can Colors Protect a Snake?

• One way to learn more about how hypothesis-based science works is to examine a case study, an in-depth examination of an actual investigation.

Copyright © 2007 Pearson Education Inc., publishing as Pearson Benjamin Cummings

• Biologists developed a hypothesis regarding mimicry in snakes.

– They tested the hypothesis by making artificial snakes and observing how often they were attacked by predators.

Figure 1.21

• This is an example of a controlled experiment.

– Such an experiment is designed to compare an

experimental group with a control group.

– Ideally, a control group and an experimental

group differ in only one variable.

The Culture of Science

• Scientists build on what has been learned from earlier research.

– They pay close attention to contemporary scientists working on the same problem.

Science, Technology, and Society

• Science and technology are interdependent.

– New technologies advance science.

– Scientific discoveries lead to new technologies.

– For example, the discovery of the structure of DNA 50 years ago led to a variety of DNA technologies.

– Technology has improved our standard of living in many ways, but it is a double-edged sword.

– Technology that keeps people healthier has enabled the human population to grow tenfold in the past 300 years.

– The environmental consequences of this population growth may be devastating.