chapter 1 the science of life. section 1-1 the study of life objectives 1.list six unifying themes...
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CHAPTER 1
The Science of Life
Section 1-1 The Study of Life Objectives
1. List six unifying themes in biology.
2. Explain how organisms get the energy they need.
3. Describe the main difference between the structure of a living thing and a nonliving thing.
In the beginning . . .
• First forms of life on earth– arose 3.5 bya – prokaryotic, unicellular, heterotrophic
Themes in Biology
• Cell structure and function
unicellular vs. multicellular
What is differentiation?
prokaryotic vs. eukaryotic
common cell parts
Themes in Biology
• Stability and Homeostasis– Organisms must control conditions such as
temperature, water content, food intake, and pH
Homeostasis – constant internal environment
Themes in Biology
• Reproduction and Inheritance– The molecule of heredity is DNA
Gene – section of DNA that codes for the development of a trait
Two types of reproduction• Sexual and Asexual
Themes in Biology
• Evolution– Populations of organisms change over time– Natural selection is the mechanism by which
evolution occurs
Themes in Biology
• Interdependence of Organisms– Ecology is the study of the interactions of
organisms with one another and with their environment
Ecosystems – environmental communities
Themes in Biology
• Matter, Energy , and Organization– Autotrophs vs. Heterotrophs
Section 1-2 The World of Biology Objectives
1. List six characteristics of life.
2. Describe how a living things is organized.
3. Explain why all living things on Earth are not yet well understood.
Characteristics of Life
• Cells– Unicellular– Multicellular
Characteristics of Life
• Organization
Organism
System
Organ
Tissue
Cells
Organelles
Molecules
Atoms
Biosphere
Biome
Ecosystem
Community
Population
Characteristics of Life
• Energy Use– Metabolism- the sum of all the chemical
processes that occur in an organism• Two Types• Anabolism
– building complex molecules from simpler ones – ex: photosynthesis
• Catabolism– breaking down complex molecules into simpler ones– ex: cellular respiration
Characteristics of Life
• Flow of Energy in an Ecosystem
Solar energy Chemical energyAUTOTROPHS HETEROTROPHS
Mechanical energy
Characteristics of Life
• Homeostasis– Necessary for survival– A reaction (response) to a change in the
environment (stimulus) helps us to maintain homeostasis
Characteristics of Life
• Growth– Results from
• Cell enlargement
• Cell division
– Is necessary for the development of an adult organism
Characteristics of Life
• Reproduction– Is necessary for the survival of the species– Two types
• Asexual– One parent cell divides to form two identical daughter
cells.
• Sexual– Two cells unite to form a new organism, different from
either parent cell.
The Living World
• Difficulties involved in studying all living things – Inaccessibility to all organisms– Some organisms are so small– Few of some species exist
Section 1-3 Scientific Methods Objectives
1. Define and give examples of observing, measuring, organizing and analyzing data, inferring, and modeling.
2. Explain the relationship between hypothesizing, predicting, and experimenting.
3. Explain why good communication is so important in science.
4. Describe the methods that scientists use in their work.
Scientific Methods
• Observing
Scientific Methods
• Asking a Question/Stating the Problem
• Collecting Data/Background Information– 1. Observing– 2. Measuring– 3. Sampling– 4. Organizing data using graphs, charts, tables,
or maps
Scientific Methods
• Hypothesizing
Hypothesis – TESTABLE statementPrediction – a statement made in advance that
states the results that will be obtained from testing a hypothesis, if the hypothesis is supported
If . . . Then . . .
Scientific Methods
• Experimenting
– Process by which a hypothesis is tested under controlled conditions
– Data which is collected and organized must then be analyzed
Scientific Methods
• Drawing Conclusions
If data are reliable, the hypothesis is supportedIf data are NOT reliable, the hypothesis is
rejected
Modeling and inferring may be used to help draw conclusions
Scientific Methods
• A hypothesis that is repeatedly tested and supported may become a THEORY!
?? What is the difference between
a theory and a law ??
Scientific Methods
• Communicate the results
review
Controlled Experiments
• Two Groups
– Control Group• Differs from the experimental group in only ONE way• Is used as a standard for comparison
– Experimental Group• Differs from control group by one factor called the INDEPENDENT
VARIABLE• The DEPENDENT VARIABLE is observed or measured in both
groups
review
Section 1-4 Microscopy & Measurement Objectives
1. Compare light microscopes and electron microscopes in terms of magnification and resolution
2. Explain the advantage of using the International System of Units (SI)
Microscopes
• Magnification and Resolution
– Magnification – the apparent increase in an object’s size
– Resolution – the ability to see detail
Microscopes
• Light microscopes– Uses light and lenses to illuminate and magnify
the image
• Electron microscopes– Uses a beam of electrons to magnify the image
Measurement
• Base Units– Length, mass, time chart
• Derived Units– Area, volume, mass density, specific volume,
temperature
• Other Units– Minute, hour, day, liter, metric ton