chapter 1 introduction: biology today. biology is the scientific study of life. the scope of life...
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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.