Transcript Biology: Exploring Life Chapter 1

Biology: Exploring Life
Chapter 1
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Figure 1.0_1
Chapter 1: Big Ideas
Themes in the Study
of Biology
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The Process
of Science
Evolution, the Core
Theme of Biology
Biology and
Everyday Life
TWO WAYS TO STUDY SCIENCE
 Discovery approach: observe and describe objects at many
levels
- ie. Dissection, Human genome project, description of DNA
 Hypothesis based approach:
- propose a hypothesis, make deduction, test prediction
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The Scientific Method
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State the problem
Research
Form a hypothesis
Prediction -if…then…
Test hypothesis
Steps to solving a problem
using the scientific method.
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Testing the hypothesis
 Control group –no changes
 Experimental group-changes
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Testing : (cont.)
Involves variables – something that changes
Two types of variables
- Independent – the one that you change
- Dependent – the one that changes because
of the independent variable
Ex-test the affect of caffeine on plant growth
independent
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dependent
Steps cont.
Record & analyze data
Charts, graphs
Bar graph represents quantitative data
Pie chart represents data in %
Form a conclusion
Replicate
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THE PROCESS OF SCIENCE
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1.8 Scientific inquiry is used to ask and answer
questions about nature
 The word science is derived from a Latin verb meaning “to know.”
Science is a way of knowing.
 Scientists
 use inductive reasoning to draw general conclusions from many
observations and
 deductive reasoning-(specific results predicted from
general idea) to come up with ways to test a hypothesis, a
proposed explanation
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1.8 Scientific inquiry is used to ask and answer
questions about nature
 How is a theory different from a hypothesis? A scientific theory is
 much broader in scope than a hypothesis,
 usually general enough to generate many new, specific hypotheses,
which can then be tested, and
 supported by a large and usually growing body of evidence.
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1.9 Scientists form and test hypotheses and share
their results
 We solve everyday problems by using hypotheses.
 A common example would be the reasoning we use to answer the
question, “Why doesn’t a flashlight work?”
 Using deductive reasoning we realize that the problem is either (1)
the bulb or (2) the batteries.
 Further, a hypothesis must be
 testable and
 falsifiable.
 In this example, two hypotheses are tested.
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Figure 1.9A_s1
Observation
Question
Hypothesis 1:
Dead batteries
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Hypothesis 2:
Burned-out bulb
Figure 1.9A_s2
Observation
Question
Hypothesis 1:
Dead batteries
Hypothesis 2:
Burned-out bulb
Prediction:
Prediction:
Replacing bulb
will fix problem.
Replacing batteries
will fix problem.
Experiment:
Test prediction by
replacing batteries.
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Experiment:
Test prediction by
replacing bulb.
Figure 1.9A_s3
Observation
Question
Hypothesis 1:
Dead batteries
Hypothesis 2:
Burned-out bulb
Prediction:
Prediction:
Replacing bulb
will fix problem.
Replacing batteries
will fix problem.
Experiment:
Test prediction by
replacing batteries.
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Test falsifies
hypothesis. Revise
hypothesis or
pose new one.
Experiment:
Test prediction by
replacing bulb.
Test does not
falsify hypothesis.
Make additional
predictions and
test them.
1.9 Scientists form and test hypotheses and share
their results
 An actual research project
 Scientists set up a mimicry experiment
 poisonous animals are brightly colored
 imposters resemble poisonous species but are actually harmless.
 They then tested the hypothesis that mimics benefit because
predators confuse them with the harmful species.
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1.9 Scientists form and test hypotheses and share
their results
 The scientists conducted a controlled experiment, comparing
 an experimental group -artificial king snakes and
 a control group -artificial brown snakes.
 The groups differed only by one factor, the coloration of the
artificial snakes.
 The data fit the prediction of the mimicry hypothesis.
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EASTERN CORAL SNAKE-VENOMOUS
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SCARLET KING SNAKE NONVENOMOUS
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Figure 1.9E
100
84%
Percent of total attacks
on artificial snakes
83%
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Artificial
brown snakes
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40
20
0
20
Artificial
king snakes
17%
Coral snakes
absent
16%
Coral snakes
present
THEMES IN THE STUDY
OF BIOLOGY-Characteristics of Life
 All forms of life share common properties
 Biology is the scientific study of life.
 Properties of life include
1. Order—the highly ordered structure that typifies life-living
cells are the basis of this
2. Reproduction—the ability of organisms to reproduce their
own kind,
3. Growth and development—consistent growth and
development controlled by inherited DNA,
4. Energy processing—the use of chemical energy to power
an organism’s activities and chemical reactions,
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All forms of life share common properties
5. Response to the environment—an ability to respond to
environmental stimuli,
6. Regulation—an ability to control an organism’s internal
environment within limits that sustain life, and
7. Evolutionary adaptation—adaptations evolve over many
generations as individuals with traits best suited to their
environments have greater reproductive success and pass their
traits to offspring.
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Figure 1.1
(1) Order
(3) Growth and
development
(4) Energy
processing
(2) Reproduction
(6) Regulation
(5) Response to the
environment
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(7) Evolutionary adaptation
1.2 In life’s hierarchy of organization, new properties
emerge at each level
 Biological organization unfolds as follows:
 Biosphere—all of the environments on Earth that support life,
 Ecosystem—all the organisms living in a particular area and the
physical components with which the organisms interact,
 Community—the entire array of organisms living in a particular
ecosystem,
 Population—all the individuals of a species living in a specific
area,
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1.2 In life’s hierarchy of organization, new properties
emerge at each level
 Organism—an individual living thing,
 Organ system—several organs that cooperate in a specific
function,
 Organ—a structure that is composed of tissues and that provides
a specific function for the organism,
 Tissues—a group of similar cells that perform a specific function,
 Cells—the fundamental unit of life,
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1.2 In life’s hierarchy of organization, new properties
emerge at each level
 Organelle—a membrane-bound structure that performs a specific
function in a cell, and
 Molecule—a cluster of small chemical units called atoms held
together by chemical bonds.
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Figure 1.2
Ecosystem:
Forest in
Madagascar
Biosphere
Madagascar
Community:
All organisms in
the forest
Population:
Group of ring-tailed
lemurs
Organism:
Ring-tailed lemur
Organ system:
Nervous system
Organ:
Brain
Spinal cord
Brain
Nerve
Tissue:
Nervous tissue
Cell:
Nerve cell
Organelle:
Nucleus
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Atom
Nucleus
Molecule:
DNA
1.3 Cells are the structural and functional units of life
 Cells are the level at which the properties of life emerge.
 A cell can
 regulate its internal environment,
 take in and use energy,
 respond to its environment,
 develop and maintain its complex organization, and
 give rise to new cells.
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1.3 Cells are the structural and functional units of life
 All cells
 are enclosed by a membrane that regulates the passage of materials
between the cell and its surroundings and
 use DNA as their genetic information.
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1.3 Cells are the structural and functional units of life
 There are two basic types of cells.
1. Prokaryotic cells
 were the first to evolve,
 are simpler, and
 are usually smaller than eukaryotic cells.
2. Eukaryotic cells
 contain membrane-enclosed organelles, including a nucleus containing DNA, and
 are found in plants, animals, and fungi.
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Figure 1.3
Eukaryotic cell
Prokaryotic
cell
DNA
(no nucleus)
Membrane
Organelles
Nucleus
(membraneenclosed)
DNA (throughout
nucleus)
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1.3 Cells are the structural and functional units of life
 Cells illustrate another theme in biology: the correlation of
structure and function.
 Structure is related to function at all levels of biological
organization.
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1.4 Living organisms interact with their environment,
exchanging matter and energy
 Living organisms interact with their environments, which include
 other organisms and
 physical factors.
 In most ecosystems
 plants are the producers that provide the food,
 consumers eat plants and other animals, and
 decomposers act as recyclers, changing complex matter into simpler
mineral nutrients.
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1.4 Living organisms interact with their environment,
exchanging matter and energy
 The dynamics of ecosystems include two major processes:
1. The recycling of chemical nutrients from the atmosphere and soil
through producers, consumers, and decomposers back to the
environment.
2. The one-way flow of energy through an ecosystem, entering as
sunlight, converted to chemical energy by producers, passed on to
consumers, and exiting as heat.
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Figure 1.4
Ecosystem
O2
O2
Sunlight
Heat
Producers
(such as
plants)
Consumers
(such as
animals)
Chemical energy
(food)
CO2
Water and minerals
taken up by tree roots
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CO2
Cycling of
chemical nutrients
Decomposers
(in soil)
EVOLUTION, THE CORE THEME OF
BIOLOGY
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1.5 The unity of life is based on DNA and a common
genetic code
 All cells have DNA, the chemical substance of genes.
 Genes
 are the unit of inheritance that transmits information from parents
to offspring,
 are grouped into very long DNA molecules called chromosomes,
and
 control the activities of a cell.
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1.5 The unity of life is based on DNA and a common
genetic code
 A species’ genes are coded in the sequences of the four building
blocks making up DNA’s double helix.
 All forms of life use essentially the same code to translate the
information stored in DNA into proteins.
 The diversity of life arises from differences in DNA sequences.
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Figure 1.5
A
G
C
C
A
T
G
T
A
C
G
T
A
A
C
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T
G
G
T
C
1.6 The diversity of life can be arranged into three
domains
 Diversity is the hallmark of life.
 Biologists have identified about 1.8 million species.
 Estimates of the actual number of species ranges from 10 to 100
million.
 Taxonomy names species and classifies them into a system of
broader groups.
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1.6 The diversity of life can be arranged into three
domains
 The diversity of life can be arranged into three domains.
1. Bacteria are the most diverse and widespread prokaryotes.
2. Archaea are prokaryotes that often live in Earth’s extreme
environments.
3. Eukarya have eukaryotic cells and include
 single-celled protists and
 multicellular fungi, animals, and plants.
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Figure 1.6
Domain Bacteria
Domain Eukarya
Bacteria
Domain Archaea
Protists
(multiple kingdoms)
Kingdom Plantae
Kingdom Fungi
Kingdom Animalia
Archaea
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1.7 Evolution explains the unity and diversity of life
 The history of life, as documented by fossils, is a saga of a changing
Earth
 billions of years old and
 inhabited by an evolving cast of life forms.
 Evolution accounts for life’s dual nature of
 kinship and
 diversity.
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1.7 Evolution explains the unity and diversity of life
 In 1859, Charles Darwin published the book On the Origin of Species
by Means of Natural Selection, which articulated two main points.
1. A large amount of evidence supports the idea of evolution, that
species living today are descendants of ancestral species in what
Darwin called “descent with modification.”
2. Natural selection is a mechanism for evolution.
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Figure 1.7B
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Figure 1.7C
1 Population with varied inherited traits
2 Elimination of individuals with certain traits
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3 Reproduction of survivors
1.7 Evolution explains the unity and diversity of life
 From these observations, Darwin inferred that
 those individuals with heritable traits best suited to the environment
are more likely to survive and reproduce than less well-suited
individuals,
 as a result of this unequal reproductive success over many
generations, an increasing proportion of individuals will have the
advantageous traits, and
 the result will be evolutionary adaptation, the accumulation of
favorable traits in a population over time.
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1.10 CONNECTION: Biology, technology, and society
are connected in important ways
 Many issues facing society are related to biology. Most involve our
expanding technology.
 The basic goals of science and technology differ.
 The goal of science is to understand natural phenomena.
 The goal of technology is to apply scientific knowledge for some
specific purpose.
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1.10 CONNECTION: Biology, technology, and society
are connected in important ways
 Although their goals differ, science and technology are
interdependent.
 Technological advances stem from scientific research.
 Research benefits from new technologies.
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1.11 EVOLUTION CONNECTION: Evolution is
connected to our everyday lives
 Evolution is a core theme of biology.
 Evolutionary theory is useful in
 medicine,
 agriculture,
 forensics, and
 conservation.
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1.11 EVOLUTION CONNECTION: Evolution is
connected to our everyday lives
 Human-caused environmental changes are powerful selective forces
that affect the evolution of many species, including
 antibiotic-resistant bacteria,
 pesticide-resistant pests,
 endangered species, and
 increasing rates of extinction.
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