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• Adaptions are the result of evolution: process of change that has transformed
life from its beginnings to the astounding array of organisms today
• Biology: scientific study of life
• Scientific inquiry: how scientists ask and attempt to answer questions about
the natural world
• Levels of biological organization
◦Biosphere-all life on earth and all the places where life exists
◦Ecosystems-all the living things in a particular area, along with all the non
living components of the environment with which life interacts (soil, water)
◦Communities-array of organisms inhabiting a particular ecosystem
◦Populations-all of the individuals of a species living within the bounds of a
specific area
◦Organisms-individual living things
◦Organs and organ systems-organs are organized into organ systems
◦Tissues-group of cells that work together to perform a specialized function
◦Cells-life's fundamental unit of structure and function
◦Organelles-various functional components present in cells
◦Molecules-chemical structure consisting of two or more units called atoms
• Five unifying themes
◦New Properties emerge at Successive Levels of Biological Organization
‣ Reductionism-the approach of reducing complex systems to simpler
components that are more manageable to study
‣ Emergent properties: at each level, properties emerge that are absent
from the preceding one, due to the arrangement and interactions of parts
as complexity increases
• Not unique to life
• Complement reductionism with systems biology: the exploration of a
biological system by analyzing the interactions among its parts
‣ Structure and function
• Analyzing a biological structure gives us clues about what it does and
how it works
• Knowing the function of something gives insight into its structure and
organization
‣ The cell: An Organism's Basic Unit of Structure and Function
• The activities of organisms are all based on the activities of cells
• All cells share certain characteristics-enclosed by membrane that
regulates passage of materials
• Two main forms: prokaryotic and eukaryotic
◦Eukaryotic: membrane enclosed organelles, some organelles found

in all and some found in just some types (chloroplasts in plants)
◦Prokaryotic: lacks a nucleus or other membrane-enclosed
organelles, generally smaller
◦Life's Processes Involve the Expression and Transmission of Genetic
Information
‣ In cells, chromosomes contain genetic material in DNA
‣ DNA Structure and function
• Before a cell divides, DNA is replicated and each of the two offspring
inherits a complete set of chromosomes
• Each chromosome contains one very long DNA molecule with
hundreds of thousands of genes, units of inheritance that encode the
information necessary to build all of the molecules synthesized within
a cell, establishing that cells identity and function
• DNA molecule is made up of two strands-made up of four nucleotides
(ATCG) that are like a four letter alphabet
• DNA provides blueprints for making proteins
• Genes control protein production indirectly using a related molecule
called RNA as an intermediary
• Gene expression: process in which the information in a gene directs
the manufacture of a cellular product
• Differences between organisms reflect differences in their nucleotide
sequences rather than their genetic codes
• Some RNA molecules are translated into proteins, but some do other
tasks like regulating the functioning of protein-coding genes
‣ Genomics: Large-Scale Analysis of DNA sequences
• Genome: Entire "library" of genetic instructions that an organism
inherits
• The entire sequence of nucleotides in the human genome is now
known
• Genomics: researchers study whole sets of genes in one or more
species
◦Made possible by "high-throughput" (tools that can analyze
biological materials rapidly), bioinformatics (Use of computational
tools to store, organize, and analyze huge volume of data that
results from high-throughout methods), and formation of
interdisciplinary research teams (melting pots of diverse specialists
like mathematicians and engineers)
◦Life requires the Transfer and Transformation of energy and matter
‣ When an organism uses chemical energy to perform work, some is

converted to thermal energy and is dissipated to its surroundings as heat
‣ Energy flows through an ecosystem, but chemical elements are recycled
within an ecosystem
◦Organisms interact with other organisms and the physical environment
‣ Organisms interact with their environment and the environment is
affected
‣ Interactions: affect participants and how populations evolve
• Mutually beneficial
• One species benefits and other is harmed
• Both species are harmed
◦Evolution, the core theme of biology
‣ Explain traits shared by two organisms due to common ancestor
• The Core Theme: Evolution Accounts for the unity and diversity of life
◦Classifying the diversity of life: the three domains of life
‣ Bacteria and archaea (extreme environments) are prokaryotic
‣ Eukarya: plantae, fungi, and animalia are multicellular and are distinguished
by their modes of nutrition: producers, consumers, absorb nutrients form
surroundings
◦Unity in the diversity of life
◦Charles Darwin and the Theory of Natural Selection
‣ Published On the Origin of Species by means of Natural Selection
• Two main points
◦species have arisen from a succession of ancestors that differed
from them: "descent with modification", displays unity in a common
ancestor and diversity in modifications
◦"Natural selection" is a mechanism for descent with modification
‣ Developed from observations that are not individually
revolutionary
• Individuals in a population vary in their traits, many of which
seem to be heritable
• A population can produce far more offspring than can survive
to produce offspring of their own; competition is inevitable
• Species generally are suited and adapted to their
environments
‣ Inferred that individuals with inherited traits that are better suited to the
local environment are more likely to survive and reproduce than are less
well-suited individuals
...
This is called natural selection
◦The Tree of Life

‣ Darwin proposed that natural selection could cause an ancestral species
to give rise to two or more descendant species over time
‣ A species could gradually radiate into multiple species as the
geographically isolated populations adapted over many generations to
different environmental conditions
‣ Darwin studied finches in the Galápagos Islands and how they adapted to
different food sources on different islands
‣ Tree diagrams are used to display descent with modification
‣ All of life is connected through its long evolutionary history
• Biological Inquiry entails forming and testing hypotheses based on observations
of nature
◦Science: "to know", way of knowing, approach to understand the natural
world, developed out of curiosity of the world
◦Inquiry: search for information and explanations for natural phenomena
‣ Includes challenge and luck, along with planning and creativity
◦Process of inquiry
‣ Making observations
• Use of senses to gather information directly or indirectly
• Recorded observations are data
◦Qualitative and quantitative
• Lead to important conclusions based on inductive reasoning: derive
generalizations from a large number of specific observations
‣ Forming and testing hypotheses
• Hypotheses is a tentative answer to a well-framed question, an
explanation on trial
◦Leads to predictions that can be tested by making more
observations of designing an experiment
• Deductive reasoning
◦From general premises, we extrapolate to the specific results we
should expect if the premises are true
◦Usually take form of predictions of results if the hypothesis
(premise) is correct
◦"If, then"
◦We can never prove that a hypothesis is true, we don't eliminate
possibilities through falsification
• Questions that can and cannot be addressed by science
◦Hypothesis must be falsifiable
◦Supernatural explanations and religious matters are outside the
bounds of science

• A Case Study in Scientific Inquiry: Investigating Coat Coloration in
Mouse Populations
◦Silicone models
‣ Control group: native coloration mice
‣ Experimental group: non-native coloration
• Experimental controls
◦Controlled experiment: one that is designed to compare and
experimental group with a control group, changing only one factor
◦Control group allows scientists to be sure that the factor affecting
predation rates was the coloration and not other factors
◦Controlled experiment does not mean that everything is constant
and one variable is changed, it's impossible
◦Researchers control unwanted variables by canceling out their
effects using control groups
• Theories in Science
◦"Evolutionary adaptations arise by natural selection"
◦General enough to spin off into many new, testable hypotheses
◦Generally supported by a much greater body of evidence than a
single hypotheses
◦Widely adopted theories explain a great diversity of observations
and are supported by a vast accumulation of evidence
◦Scientists must modify or reject theories when new research
methods that produce results that don't fit
• Science as a Social Process: Community and Diversity
◦ Science is Social activity: work in teams, collaboration, etc
◦Scientists check each other's results
◦Biologists approach questions form different angles
◦Research community is part of a society at large
◦Goal of Technology is to apply scientific knowledge for some
specific purpose
◦Science and technology are interdependent
◦Sciences stand to gain much from embracing a diversity of
backgrounds and viewpoints among its practitioners
◦Women and different racial groups have increased in relevance, but
are still underrepresented



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