Chapter 1 – Exploring Life
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Biology’s Most Exciting Era
a. Biology – the scientific study of life
b. Biology is a quest, an ongoing inquiry about the nature of life
c. We recognize life by what living things do
d. Some of the properties and processes we associate with life
i. Order – Highly ordered structure that characterizes life
ii. Evolutionary Adaptation – Adaptation evolves over many generations by
the reproductive success of those individuals with heritable traits that are
best suited to their environments
iii. Response to the environment – Stimulation by environment
iv. Regulation – Homeostasis, maintaining body heat
v. Energy Processing – Eating, turn food into chemical energy
vi. Growth and development – Genes control the pattern of growth and
development
vii. Reproduction – Organisms reproduce their own kind
Concept 1.1 (Biologists explore life from the microscopic to global scale)
a. A Hierarchy of Biological Organization
i. The biosphere – The biosphere consists of all environments on Earth that
are inhabited by life. It includes most regions of lands, most bodies of
water, and the atmosphere to a fairly high altitude.
ii. Ecosystems – Grasslands, deserts, and the ocean’s coral reefs (as well as
trees) are examples of ecosystems. Ecosystems consists of all the living
things in a particular area, along with all the nonliving components of the
environment with which life interacts, such as soil, water, atmospheric
gases, and light. All ecosystems make the biosphere
iii. Communities – The entire array of organisms inhabiting a particular
ecosystem is the community. The different forms of life are called species.
iv. Populations – Each of the group of each individual species living within
the bounds of a specified area.
v. Organisms – Individual living things. One frog is one organism.
vi. Organs and Organ systems – A body part consisting of two or more
tissues are organs. These organs function together to create an organ
system, a system that works together to do a specific function.
vii. Tissues – Tissues form organs, but are composed of many different cells.
viii. Cells – Life’s fundamental unit of structure and function. Some organisms
are single celled, some are multicellular. A human body has trillions of
microscopic cells.
ix. Organelles – the various functional components that make up cells.
x. Molecules – a chemical structure consisting of two or more small chemical
units called atoms.
A Closer Look at Ecosystems
a. Each organism interacts continuously with its environment, which includes other
organisms as well as non living factors.
b. Both organism and environment are affected by the interactions between them.
c. Ecosystem dynamics – There are two major processes that create the dynamics of
any ecosystem.
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i. One process is the cycling of nutrients. (All plant minerals will eventually
be returned to the soil by microorganisms that decompose leaf litter, dead
roots and other organic debris)
ii. The second process is the flow of energy from sunlight to producers to
consumers.
1. Producers – plants that convert light energy to chemical energy
2. Consumers – organisms, such as animals, that feed on producers
and other consumers
d. Energy Conversion
i. Work depends on a source of energy. Exchange of energy between
organism and surroundings involve transformation of one form of energy
to another.
ii. Animals convert chemical energy to kinetic energy
iii. Energy flows through an ecosystem, entering as light, existing as heat.
A Closer Look at Cells
a. The cell is the lowest level of organization that can perform all activities required
for life.
b. The Cell’s Heritable Information
i. Chromosomes are made up of deoxyribonucleic acid, or DNA.
ii. DNA is the substance of genes, the units of inheritance that transmit
information from parents to offspring.
iii. Each chromosome has one very long DNA molecule with hundred or
thousands of genes arranges along its length.
iv. Each DNA molecule is made up of two long chains arrange into what is
called the double helix.
v. Each link of a chain is one of four kinds of chemical building blocks
called nucleotides (ATCG).
vi. Most genes program the production of proteins.
vii. The entire ‘library’ of genetic instructions that an organism inherits is
called its genome.
c. Two Main Forms of Cells
i. There are two forms of cells, Prokaryotic (bacteria and archaea) and
Eukaryotic (everything else).
1. Eukaryotic Cell
a. Subdivided by internal membranes into various membraneenclosed organelles.
b. In most cells, the largest organelle is the nucleus, which has
the cell’s DNA.
c. Other organelles within the cytoplasm, the area between
nucleus and outer membrane of the cell.
2. Prokaryotic Cell
a. The DNA in a prokaryotic cell is not separated from the
rest of the cell via nucleus (no nucleus).
b. Also does not have any other kinds of organelles.
Concept 1.2 - Biological systems are much more than the sum of their parts
a. System – a combination of components can form a complex organization called
this.
b. The future of biology is understanding the behavior of whole, integrated systems.
VI.
The Emergent Properties of Systems
a. Emergent properties – novel properties that emerge that are not present in the
level below.
i. This is due to the arrangement and interaction of parts as complexity
increases
b. Emergent properties are neither supernatural nor unique to life. However, in life,
biological systems are very complex.
VII. The Power and Limitations of Reductionism
a. Reductionism – reducing complex systems to simpler components that are much
more manageable to study.
i. We cannot fully explain a higher level of order by breaking it down into
parts.
ii. However, something as complex organism or a cell cannot be analyzed
without taking it apart.
VIII. Systems Biology
a. The ultimate goal of systems biology is to model the dynamic behavior of whole
biological systems.
b. The aim of systems biology is to make progress answering such big questions.
c. Systems Biology is necessary in the study of life at all levels.
d. It is necessary to inventory as many parts as possible, such as all the known genes
and proteins in a cell (reductionism).
e. It has taken three key research developments to bring systems biology within
reach:
i. High-throughput technology – SB depends on methods that can analyze
biological materials quickly and produce enormous volumes of data.
ii. Bioinformatics – huge databases that results from high throughput
technology, a storage of useful biological information
iii. Interdisciplinary research teams – Teams of diverse specialist depending
on each field.
IX.
Feedback Regulation in Biological Systems
a. There is a supply and demand economy that supplies to some of the dynamics of
biological systems.
b. The key is the ability of many biological processes to self regulate by a
mechanism called feedback.
c. In feedback regulation, the output, or product, of a process regulates that very
process.
i. Negative feedback – the most common form of regulation, in which
accumulation of an end product of a process slows that process. For
example, the production of ATP.
ii. Positive feedback – less common form of regulation in which an end
product speeds up production. For example, blood clotting.
X.
Concept 1.3 – Biologists explore life across its great diversity of species
a. Diversity is the hallmark of life.
XI.
Grouping Species: The Basic Idea
a. It is a human tendency to group diverse items according to similarities.
b. Taxonomy, the branch of biology that names and classifies species, formalized
this ordering of species into a series of groups of increasing breadth.
XII. The Three Domains of Life
a. All kingdoms of life can be grouped into three domains.
i. Domain Bacteria and Domain Archaea
1. Prokaryotes, unicellular and microscopic. Used to be group in one
Kingdom called Monera, but now seen to represent two very
distinct branches of prokaryotic life.
2. Archaea are closely related to Eukaryotic organisms rather than the
Bacteria.
ii. Domain Eukarya
1. All organisms with eukaryotic cells are grouped in this Domain.
2. There are three kingdoms in this Domain, Plantae, Fungi, and
Animalia.
3. Plants produce their own sugars by photosynthesis, Fungi are
decomposers that absorb tridents by breaking down dead
organisms, and Animals obtain food by eating.
XIII. Unity in the Diversity of Life
a. Life’s dual nature of unity and diversity – The process of evolution illuminated
both similarities and differences among Earth’s life
XIV. Concept 1.4 – Evolution accounts for life’s unity and diversity
a. Charles Darwin published his book On the Origin of Species by Natural Selection.
i. It articulated two main points; a succession of ancestors (descent with
modification), common ancestors, and natural selection; mechanism for
descent with modification.
XV. Natural Selection
a. Observations that lead to his theories
i. Observations: Individual Variation, individuals in a population vary in
many heritable traits… - Overproduction and competition, Any species
that has potential to produce the most offspring will survive longer.
ii. Inferences: Unequal reproductive success, not all populations have the
same chance of reproducing and surviving…… - Evolutionary adaptation,
Populations with reproductive success will adapt to environments and
increase frequency in populations.
b. It is natural selection because the natural environment selects the animal due to
certain circumstances and adaptation.
XVI. The Tree of Life
a. The limb anatomy of all mammalians are very similar, a structure from a common
ancestor.
b. Natural selection was seen as a split into more descendant species.
c. The beaks of finches was one of his observations, depending on where they lived,
the size of the beaks got either bigger or smaller.
d. It only tags back to how ancient of an ancestor.
XVII. Concept 1.5 – Biologist use various forms of inquiry to explore life
a. Science - Latin for ‘to know’.
b. Inquiry – a search for information and explanation, often focusing on specific
questions. This is what drove Darwin to seek on how the people adapted.
c. Inquiry helps us understand biological unity and diversity.
d. Science is not as structured as most people realized; there is not set in stone
method of scientific inquiry.
e. But there are two main processes of scientific inquiry
i. Discovery science – describing nature
ii. Hypothesis based science – explaining nature
XVIII. Discovery Science
a. Discovery science is also called descriptive science – describes natural structures
and processes as accurately as possible through careful observation and analysis
of data.
b. Types of Data
i. Recorded Observations (uses of senses to gather information, directly or
indirectly) are called data.
ii. There are two kinds of data
1. Qualitative – Recording descriptions rather than numerical
measurements.
2. Quantitative - Numerical measurements, amounts.
c. Induction In Discovery Science
i. Induction, or inductive reasoning, is a type of logic in which we derive
generalizations based on large number of specific observations.
XIX. Hypothesis Based Science
a. In science, we use Hypothesis based explanations in order to figure out answers
and causation.
b. The Role of Hypotheses in Inquiry
i. Hypothesis – tentative answer to a well-framed question – an explanation
or a trial.
ii. Educated postulate, makes predictions that can be tested.
c. Deduction: The “If… then” Logic of Hypothesis-Based Science
i. Deduction is based on hypothesis science.
ii. Deductive Reasoning, the logic flows in the opposite direction, from
general to specific.
iii. Deduction takes form in predictions of outcomes.
d. A Closer Look at Hypothesis in the Scientific Inquiry
i. Hypothesis must be testable; there must be a way to check.
ii. Hypothesis must be falsifiable; there must be an observation that proves it
untrue.
iii. Testing supports that hypothesis not by proving that it is correct, but by
not eliminating it through falsification.
iv. It is impossible to prove a hypothesis beyond a shadow of doubt, there are
millions of test per hypothesis.
e. The Myth of the Scientific Method
i. Scientific method is an effective way to make a hypothesis test. Discovery
science has contributed to much of our understanding of nature, but
scientific method helps figure out the causation.
XX.
A Case Study in Scientific Inquiry: Investigating Mimicry in Snake Populations
a. Example of controlled experiments; relatively harmless animals mimic the
stinging animals in order to provide defense, a hypothesis.
b. DESIGNING CONTROLLED EXPERIMENTS
i. Controlled experiment, where an experimental group, is compared with a
control group.
ii. It is to check if the only thing that differs (the only factor) is the factor in
which it only differed from the one thing it tried to test.
iii. In a controlled experiment, the scientist do not keep everything constant,
but rather attempt to eliminate unwanted factors by cancelling effects in
control groups!
XXI. Limitations of Science
a. Only so many things can be counted as good evidence and many eyewitness
accounts are very dull and boring; observations must be proved.
XXII. Theories in Science
a. Scientific theory is much broader in scope than a hypothesis.
i. Theory is general enough to spin off many new hypothesis that can be
tested.
ii. Theory is generally supported by a much more massive body of evidence.
b. Everyday meaning – untested speculation
XXIII. Model Building in Science
a. Scientific models can take many forms, such as diagrams, graphs, three
dimensional objects, computer programs, or mathematical equations.
XXIV. The Culture of Science
a. Movies and cartoons portray scientist as loners in isolated labs. It actually is a
intense social activity.
b. Cooperation and competition characterize scientific culture; scientists want to get
there first.
c. Some may argue that science is no longer objective; rather it is just another view.
It is somewhere in the middle though, not perfectly objective, but an attempt.
XXV. Science, Technology, and Society
a. Though science and technology sometimes employ similar inquiry patterns, their
basic goals differ.
b. The goal of science is to understand natural phoneme. Technology applies
scientific knowledge for some specific purpose. Scientists are more discovery,
Technology are more inventions.
c. However, directions in technology depend less on the curiosity, and more on the
‘should we do it’ than the ‘can we do it’.
XXVI. A set of themes connects the concept of Biology
a. The Cell
j, k. Scientific Inquiry + Science, Technology and Society
b. Heritable information
c. Emergent Properties of Biological Systems
d. Regulation
e. Interaction with Environment
f. Energy and Life
g. Unity and Diversity
h. Evolution
i. Structure and Function