Transcript PowerPoint Chp 1

Concepts and Methods in Biology
Starr/Taggart’s
Biology:
The Unity and Diversity of Life,
Chapter 1
9e
Key Concepts:
There is unity and diversity in the world of life
Theories of evolution and natural selection
explain life’s diversity
Biology is based on observations, hypotheses,
prediction, and experimental tests
DNA, Energy, and Life
 All organisms consist of one or more cells
 Cells arise only from pre-existing cells
 The signature molecule of cells is DNA
 DNA encodes protein-building instructions
 RNAs help carry out these instructions
Objects Built from the Same Material
but with Different Instructions
Nothing Lives Without Energy
Energy = The capacity to do work
Everything has some amount of energy
All events involve a transfer of energy
Metabolism
Capacity to obtain and convert energy from
surroundings
 Capacity to use energy in maintenance and growth
Sensing and Responding
Receptors detect stimuli
Stimuli are forms of energy
Cells adjust metabolic activities in response to
stimuli detected by receptors
These responses maintain homeostasis
Internal operating conditions remain within tolerable
limits
Levels of Biological Organization
Hierarchy of Organization
Levels of Biological Organization
Hierarchy of Organization
Interdependencies Among
Organisms
Producers:
Make their own food
Consumers:
Depend on energy stored in tissues of producers
Decomposers:
Break down molecules to simpler materials
Energy Flow & Materials Cycling
Classification
Species
Genus
Family
Order
Class
Phylum
Kingdom
Six Kingdoms
Archaebacteria
Fungi
Anaerobic cells
Multicelled
Prokaryotic
Decomposers
Eubacteria
Bacteria
Prokaryotic
Protista
Single and multicelled
Eukaryotic
Eukaryotic
Plantae
Photosynthetic
Eukaryotic
Animalia
Consumers
Eukaryotic
An Evolutionary View of Diversity
Mutation
Molecular change in DNA
Original source of variations in heritable traits
May be harmful, harmless, or beneficial
Adaptive trait:
Any trait that helps an organism survive and
reproduce
Whether a trait is adaptive or not depends on
prevailing conditions
Evolution
Genetically based change in a line of descent
over time
Darwin’s theory of evolution by natural selection
explains the connection between evolution and
variation in traits
Natural Selection
Individuals in a population vary in some
heritable traits
Some heritable traits are more adaptive under
prevailing conditions
Differences in heritable traits influence survival
and reproduction of individuals
Adaptive traits become more common in
population
Biological Inquiry
Observe nature
Develop hypothesis
Make testable prediction
If tests do not confirm prediction,
consider why
Repeat tests or devise new ones
Analyze and report test results
Sequence of Steps in
Scientific Experiment
Scientific Theory
A testable hypothesis about the cause or causes
of a broad range of related phenomena.
Remains open to tests, revision, and tentative
acceptance or rejection
Darwin’s view of natural selection is a respected
scientific theory