Download Biology and the Living World

Biology and the Living World
1.1 The Diversity of Life
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Biology is the study of life. Although all living organisms share common characteristics, they are
also diverse and are therefore categorized into six groups called kingdoms.
The six kingdoms are Archaea, Bacteria, Protista, Fungi, Plantae, and Animalia
(241.0K) .
(figure 1.1)
1.2 Properties of Life
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All living organisms share five basic properties: cellular organization, all living organisms are
composed of cells; metabolism, all living organisms use energy; homeostasis, all living
organisms maintain stable internal conditions; growth and reproduction, all living organisms
grow and reproduce; heredity, all living organisms possess genetic information that determines
how each organism looks and functions, and this information is passed on to future generations.
1.3 The Organization of Life
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Living organisms exhibit increasing levels of complexity within their cells, within their bodies,
and within ecosystems (figure 1.4a) (146.0K) (figure1.4b) (139.0K) .
Novel properties that appear in each level of the hierarchy of living organisms are called
emergent properties. These properties are the natural consequences of ever more complex
structural organization.
1.4 Biological Themes
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Five themes emerge from the study of biology: evolution, the flow of energy, cooperation,
structure determines function, and homeostasis. These themes are used to examine the
similarities and differences among organisms (table 1.1) (109.0K) .
The Scientific Process
1.5 How Scientists Think
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Scientists use reasoning when examining the world. Deductive reasoning is the process of using
general principles to explain individual observations. Inductive reasoning is the process of using
specific observations to formulate general principles (figure 1.5) (107.0K) .
1.6 Science in Action: A Case Study
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The scientific investigation of the "ozone hole" revealed that industrially produced CFCs were
responsible for the thinning of the ozone layer in the earth's atmosphere (figure 1.6) (84.0K) .
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1.7 Stages of a Scientific Investigation
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Scientific investigations involve using observations to formulate hypotheses. Hypotheses are
possible explanations of these observations that can be used in forming predictions that can be
tested experimentally. Some hypotheses are rejected based on experimentation, while others are
tentatively accepted.
Scientific investigations use a series of six stages, called the scientific process, to study a
scientific question. These stages are observations, forming hypotheses, making predictions,
testing, establishing controls, and drawing conclusions (figure 1.7) (80.0K) .
Hypotheses that hold up to testing over time are sometimes combined into statements called
theories. Theories carry a higher degree of certainty, although no theory in science is absolute.
The process of science was once viewed as a series of "either/or" predictions that were tested
experimentally. This process, referred to as the scientific "method," did not take into account the
importance of insight and imagination that are necessary to good scientific investigations.
Core Ideas of Biology
1.9 Four Theories Unify Biology as a Science
There are four unifying themes in the study of biology: cell theory, gene theory, the theory of
heredity, and the theory of evolution.
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The cell theory states that all living organisms are composed of cells, which grow and reproduce
to form other cells (figure 1.10) (174.0K) .
The gene theory states that long molecules in the cell, called DNA, encode instructions for
producing cellular components. These instructions, organized into discrete units called genes,
determine how an organism looks and functions (figure 1.12a) (109.0K) (figure 1.12b)
(98.0K) .
The theory of heredity states that the genes of an organism are passed as discrete units from
parent to offspring through a process of heredity (figure 1.13) (86.0K) .
The theory of evolution states that modifications in genes that are passed from parent to
offspring result in changes in future generations. These changes lead to greater diversity among
organisms over time, ultimately leading to the formation of new groups of organisms (figure
1.15a) (130.0K) (figure 1.15b) (94.0K) and (figure 1.16) (95.0K) .
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