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BIOL 105W:
General Biology I
Properties of Life
Student Learning Outcomes
Describe the characteristics that distinguish living organisms from
nonliving matter.
Describe the hierarchical categorization of living matter from atoms to
biosphere and from species to domains.
Explain how evolution by vertical descent and horizontal transfer help
explain the unity and diversity of life.
Define and describe the concepts of genomes and proteomes.
Define science as a process by indicating its key aspects.
Design an experiment to test a given hypothesis using the procedures
and terminology of the scientific method.
Explain the difference between hypothesis testing and discovery-based
science.
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What is Science?
...the observation, identification, experimental
investigation, and theoretical explanation of natural
phenomena.
...an orderly process of posing and answering questions
about the natural world through repeated and unbiased
experiments and observations
“Science is... a progression of approximations toward the
truth.”
Peter Price, 1980
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Levels of Biological Study
Specialized biologists study properties of life at different levels.
specialty depends on the researchers’ interests and the tools they
require.
Before high-quality microscopes, organismal disciplines were developed.
ecology, zoology, botany, anatomy, and physiology
After microscopes, suborganismal disciplines developed.
cell biology
Genetic tools fostered development of subcellular disciplines.
molecular biology
Reductionism is being replaced with systems biology approach.
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Hypotheses and Theories
Hypothesis = a proposed explanation for a natural phenomenon.
based on previous observations or experiments, and existing theories
the basis for a scientific study that can support or reject the hypothesis
can be proven to be false, but NEVER proven to be true.
Useful hypotheses allow for predictions that can be evaluated in a scientific
manner.
Theory (in science) = broad explanation of some part of the natural world that is
substantiated by large amounts of evidence.
incorporates evidence from observations, hypothesis testing, and laws from other
scientific disciplines like chemistry and physics
differs from theory in everyday language.
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Two Research Approaches
Discovery Science:
collection and analysis of data without a preconceived hypothesis
drugs companies test 100s–1000s of drugs to determine if any are useful.
genes have been identified without knowing their function
goal is to gain enough information to propose hypotheses
Hypothesis Testing = Scientific Method
observation ➔ hypothesis ➔ prediction ➔ experimentation ➔ data analysis
(results) ➔ accept or reject hypothesis (conclusion)
experimental group often compared to control group
only one variable differs
complex experiments may have multiple control groups
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Cystic Fibrosis (CF) Example
CF is a disease that affects 1 in 3,500 Americans
abnormally thick and sticky mucus interferes with lung, pancreas, and liver
functions; life span about 30 years.
Discovery Science:
showed that CF is a recessive genetic trait
identified CF gene
allowed use of genetic screening tests
Hypothesis Testing:
CF gene encodes a Cl– transport protein found on cell surface
cells from CF patient were found to be defective in Cl– transport
introduction of normal CF gene in cells derived from a CF patient showed
normal Cl– transport.
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Unity and Diversity of Life
The features of “life” are shared by all living things.
this unity is rooted in biological evolution.
unbroken lineage of living things.
Different living things are similar, but they are not exactly the
same.
diversity results because ecological pressures shape
evolutionary processes differently under different
conditions.
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7 Unifying Characteristics
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7 Unifying Characteristics
Cellular basis of organization
Energy use and metabolism
Response to environmental change
Regulation and homeostasis
Growth and development
Reproduction
Biological evolution
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Levels of Organization
Hierarchical
organization
Atoms
Molecules
Cells
Tissues
Organs
Organism
Population
Community
Ecosystem
Biosphere
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Connected by Evolutionary History
Unity of all organisms best explained
by common ancestry.
primitive “cells/organisms”
provided raw material for diversity
among currently living organisms.
traits within populations became
modified over time.
vertical descent with mutation
horizontal gene transfer
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Vertical Descent
New species evolve
from existing
species within a
lineage.
mutations
accumulate during
the production of
new species.
beneficial mutations
remain following
natural selection.
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Horizontal Transfer
Evolution also occurs through
genetic exchange between
distantly-related species.
“rarely” individuals from different
species are capable of
reproducing sexually.
offspring are generally sterile.
more commonly genetic
information is transferred
asexually.
e.g., transfer of antibiotic
resistance between bacteria
species
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Web of Life?
Tree of Life is
traditional view.
shows vertical
evolution
overlooks
horizontal transfer
Web of Life is more
appropriate
incorporates
vertical evolution
and horizontal
transfer
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Biological Classification
Systematics
process of grouping species
Taxonomy
process of naming species and groups of species.
Classification scheme is hierarchical
3 domains
2 contain prokaryotic organisms
Bacteria and Archaea
1 contains eukaryotes
Eukarya
Domains are further subdivided (K, P, C, O, F, G, S)
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Classification Example
Species given
binomial name
Genus +
specific epithet
always italicized
or underlined
Species grouped
in increasingly
inclusive groups
Jaguar example
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Genomes and Proteomes
Genome=all
genes (DNA) in
an organism
from parents
unbroken
lineage
Genes are
patterns for
protein
production
proteome=all
proteins in an
organism
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Connections Among Biological
Levels
Panthers (black) and jaguars (tan) are the same species.
color differs because they possess different enzymatic proteins.
proteins differ because versions of genes (alleles) differ
genome ➔ proteome ➔ physical features
evolution shapes distribution patterns of panthers and jaguars.
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Summary
Living things share common features and are distinct from non-living
things.
Evolution is a mechanism that explains the similarities and differences
between related organisms.
A natural hierarchy describes the organization of living things.
A constructed hierarchy describes the systematics of living things.
Evolution primarily occurs by vertical descent, but may also occur due
to horizontal gene flow.
Science provides a mechanism for us to test our understanding of
natural cause-and-effect relationships.
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Eyepiece
Body Tube
Revolving Nosepiece
Objective Lens
Condenser
Stage
Clips
Diaphragm
Light
Arm
Stage
Coarse Focus
Fine Focus
Base
Microscope terms
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Magnification: enlarging object
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Resolution: clear, sharp image
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Contrast: difference between light and dark
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Parfocal: image remains nearly focused when switching
objectives.
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Parcentered: image remains nearly in the center when
switching objectives.
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Scientific Writing
To communicate work in writing for journal submission,
scientists follow the format below:
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Title
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Abstract
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Introduction
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Materials and Methods
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Results
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Conclusion
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References Cited
You will write 5 lab reports this semester.
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Scientific Writing
Title and Title Page
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To the point, but descriptive
TITLE
Your name
College Biology 105
Mrs. Campeau
Due Date
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Scientific Writing
Abstract
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Summarizes the hypothesis and methods, highlights results,
and mentions the conclusion.
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No more than 250 words.
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LAST thing that you write, but is placed at the beginning of
the paper.
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Scientific Writing
Introduction
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Provides reason for the investigation and some background.
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States the question, hypothesis, and prediction.
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General outline:
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Heading in bold.
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State purpose and question.
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Give background information, cite previous research.
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Restate question. State hypothesis and prediction.
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Scientific Writing
Introduction
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Citation placement:
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At the end of the sentence, using only author’s name and
year (Campeau, 2012).
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At the beginning of the sentence: Campeau (2012) states
that….
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If more than one author, use the author’s name followed
by et al. For example: (Campeau, et al., 2012). et al.
means: and others.
If you cite someone in your paper, they should be listed in
your references cited section.
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Scientific Writing
References Cited
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Placed at the end of the paper, generally on its own page.
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Should list all cited authors.
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Place in alphabetical order.
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You will generally need at least two citations.
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Scientific Writing
Materials and Methods
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Written in a way that someone else could repeat your
experiment.
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NOT a recipe; try not to use words like ‘then’, ‘first, second,
etc., ‘next’… Should be a narrative, not a list of steps.
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Do NOT list materials.
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Simple and precise
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Often the first part your will write.
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Scientific Writing
Results
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Highlights data.
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Does NOT make any conclusions!
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Includes tables and/or figures.
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Title, labels, cited in text
General outline:
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Restate problem/question
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Highlight important pieces of data.
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Tables and/or graphs after text; do not split.
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Scientific Writing
Discussion/Conclusion
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Final analysis and conclusions.
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Discuss WHY things happened as they did.
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Discuss possible errors and improvements for next time.
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General outline:
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Restate question, hypothesis, and prediction and if they
were correct (accepted) or rejected.
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Explain WHY you received the data you did. Use other
research to support your experiment (if possible).
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Mention any reasons for error that could influence data.
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Suggest future topics of research; what is the next step?
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