This document provides an overview of key concepts in biology and the scientific process. It discusses putting biology into context using scientific inquiry, which involves making observations, forming hypotheses, performing experiments, and analyzing data. It also discusses types of sources like primary sources that publish original research and secondary sources that review and comment on primary sources. Scientific journals are described as articles being submitted by researchers and peer-reviewed. The scientific process is outlined as involving observation, developing a hypothesis, experimentation, and analysis. Finally, it notes that scientific findings should be independently verifiable.

1. Putting Biology
into some context

4. Scientific
Inquiry

5. 1.5 - 1.8,
0.3 - 0.4

6. Scientific
Inquiry

7. Comparing
thoughts
with reality

9. 1, 1, 2, 3, 5, 8, •••

10. Inductive
Reasoning

11. Specific to General

12. 1, 2, 4, 8, 16, •••

13. 1, 1, 2, 3, 5, 8, •••

14. Deductive
Reasoning

15. General to Specific

16. Forensics

17. The
Scientific
Process

19. A template
for learning about
the physical world

20. Observation

21. Look
Listen
Smell
Touch
(Taste)

22. Hypothesis

23. Hypotheses
must be
falsifiable

29. Absence of evidence
isn’t
evidence of absence.

30. The Black Swan

32. Scientific findings should be
independently verifiable

33. Water boils at
100C at 1atm
for everyone

34. Atrazine

35. Herbicide
Widely used
Inexpensive
Increases yields 1-6%

37. Tyrone
Hayes
http://www.nationalgeographic.com/
field/explorers/tyrone-hayes.html

38. How would you figure out
if Atrazine has any effect on frogs?

40. Make Observations
Form Hypotheses
Perform Experiments
Analyze Data
???

41. Dissemination of
Scientific Findings

46. Kinds of
Sources

47. Primary Sources
publish original research
Scholarly journal articles, dissertations

48. Secondary Sources
refer to, review, comment on or critique
primary sources
Popular press articles, textbooks,
encyclopedias, science books

49. Scientific
Journals

50. Articles in scientific journals are...
submitted by researchers,
considered by editors and
peer-reviewed.

51. Hermaphroditic, demasculinized frogs after exposure
to the herbicide atrazine at low ecologically
relevant doses
Tyrone B. Hayes*, Atif Collins, Melissa Lee, Magdelena Mendoza, Nigel Noriega, A. Ali Stuart, and Aaron Vonk
Laboratory for Integrative Studies in Amphibian Biology, Group in Endocrinology, Museum of Vertebrate Zoology, Department of Integrative Biology,
University of California, Berkeley, CA 94720-3140
Communicated by David B. Wake, University of California, Berkeley, CA, March 1, 2002 (received for review December 20, 2001)
Atrazine is the most commonly used herbicide in the U.S. and human choriogonadotropin (1,000 international units) 6 h before
probably the world. It can be present at several parts per million in harvesting gametes. Eggs were manually stripped from the
agricultural runoff and can reach 40 parts per billion (ppb) in female and fertilized in vitro in 0.3 modified mammalian
precipitation. We examined the effects of atrazine on sexual Ringer’s solution by using the sperm obtained from the dissected
development in African clawed frogs (Xenopus laevis). Larvae were testes of the three males. The embryos were allowed to hatch.
exposed to atrazine (0.01–200 ppb) by immersion throughout After 4 days, the larvae were all mixed and netted into tanks 5
larval development, and we examined gonadal histology and at a time repeatedly, until all tanks contained 30 larvae. Larvae
laryngeal size at metamorphosis. Atrazine (>0.1 ppb) induced were reared in 4 liters of aerated 10% Holtfreter’s solution (15)
hermaphroditism and demasculinized the larynges of exposed and fed a solution of ground Purina rabbit chow daily. Food
males (>1.0 ppb). In addition, we examined plasma testosterone levels were adjusted as the animals grew to maximize growth.
levels in sexually mature males. Male X. laevis suffered a 10-fold
decrease in testosterone levels when exposed to 25 ppb atrazine. Dosing. In Exp. 1, we exposed larvae to atrazine at nominal
We hypothesize that atrazine induces aromatase and promotes the concentrations of 0.01, 0.1, 1.0, 10.0, and 25 parts per billion
conversion of testosterone to estrogen. This disruption in steroi- (ppb), whereas the second experiment used 0.1, 0.4, 0.8, 1.0, 25,
dogenesis likely explains the demasculinization of the male larynx and 200 ppb atrazine. Concentrations were confirmed by two
and the production of hermaphrodites. The effective levels re- independent laboratories (PTRL West, Richmond, CA, and the
ported in the current study are realistic exposures that suggest that Iowa Hygienic Laboratory, Univ. of Iowa, Iowa City, IO). All
other amphibian species exposed to atrazine in the wild could be stock solutions were made in ethanol (10 ml), mixed in 15-gallon
at risk of impaired sexual development. This widespread com- containers, and dispensed into treatment tanks. Controls were
pound and other environmental endocrine disruptors may be a treated with ethanol such that all tanks contained 0.004%
factor in global amphibian declines. ethanol. Water was changed and treatments were renewed once
every 72 h. Each treatment was replicated 3 times with 30
I n the last 10 years, a great deal of attention has focused on the
global presence of endocrine-disrupting contaminants in the
environment (1, 2). Similarly, a great deal of attention has
animals per replicate (total of 90 animals per treatment) in both
experiments. All treatments were systematically rotated around
the shelf every 3 days to ensure that no one treatment or no one
focused on global amphibian declines (3, 4). In the case of tank experienced position effects. Experiments were carried out
amphibian declines, efforts focus on identifying causes (5), at 22°C with animals under a 12-h 12-h light dark cycle (lights

53. Popular press
can be misleading

55. ARTICLE
Audible Television and Decreased Adult Words,
Infant Vocalizations, and Conversational Turns
A Population-Based Study
Dimitri A. Christakis, MD, MPH; Jill Gilkerson, PhD; Jeffrey A. Richards, MA; Frederick J. Zimmerman, PhD;
Michelle M. Garrison, PhD; Dongxin Xu, PhD; Sharmistha Gray, PhD; Umit Yapanel, PhD
Objective: To test the hypothesis that audible televi- Outcome Measures: Adult word counts, child vocal-
sion is associated with decreased parent and child izations, and child conversational turns.
interactions.
Results: Each hour of audible television was associated
Design: Prospective, population-based observational with significant reductions in age-adjusted z scores for child
study. vocalizations (linear regression coefficient, −0.26; 95% con-
fidence interval [CI], −0.29 to −0.22), vocalization dura-
Setting: Community. tion (linear regression coefficient, −0.24; 95% CI, −0.27
to −0.20), and conversational turns (linear regression co-
Participants: Three hundred twenty-nine 2- to 48- efficient, −0.22; 95% CI, −0.25 to −0.19). There were also
month-old children. significant reductions in adult female (linear regression
coefficient, −636; 95% CI, −812 to −460) and adult male
Main Exposures: Audible television. Children wore
(linear regression coefficient, −134; 95% CI, −263 to −5)
word count.
a digital recorder on random days for up to 24
months. A software program incorporating automatic
Conclusions: Audible television is associated with de-
speech-identification technology processed the creased exposure to discernible human adult speech and
recorded file to analyze the sounds the children were decreased child vocalizations. These results may ex-
exposed to and the sounds they made. Conditional lin- plain the association between infant television exposure

56. Finding
Primary-Source
Information

59. Title
Abstract
Introduction
Methods
Results
Discussion
Conclusion

60. Title
Abstract
Introduction
Methods
Results
Discussion
Conclusion

61. Laboratory for Integrative Studies in Amphibian Biology, Group in Endocrinology, Museum of Vertebrate Zoolo
University of California, Berkeley, CA 94720-3140
Communicated by David B. Wake, University of California, Berkeley, CA, March 1, 2002 (received for review Dece
Atrazine is the most commonly used herbicide in the U.S. and human choriogonadotropin
probably the world. It can be present at several parts per million in harvesting gametes. Eggs
agricultural runoff and can reach 40 parts per billion (ppb) in female and fertilized in
precipitation. We examined the effects of atrazine on sexual Ringer’s solution by using t
development in African clawed frogs (Xenopus laevis). Larvae were testes of the three males.
exposed to atrazine (0.01–200 ppb) by immersion throughout After 4 days, the larvae w
larval development, and we examined gonadal histology and at a time repeatedly, until
laryngeal size at metamorphosis. Atrazine (>0.1 ppb) induced were reared in 4 liters of a
hermaphroditism and demasculinized the larynges of exposed and fed a solution of gro
males (>1.0 ppb). In addition, we examined plasma testosterone levels were adjusted as the
levels in sexually mature males. Male X. laevis suffered a 10-fold
decrease in testosterone levels when exposed to 25 ppb atrazine. Dosing. In Exp. 1, we exp
We hypothesize that atrazine induces aromatase and promotes the concentrations of 0.01, 0.
conversion of testosterone to estrogen. This disruption in steroi- (ppb), whereas the second
dogenesis likely explains the demasculinization of the male larynx and 200 ppb atrazine. Co
and the production of hermaphrodites. The effective levels re- independent laboratories (
ported in the current study are realistic exposures that suggest that Iowa Hygienic Laboratory
other amphibian species exposed to atrazine in the wild could be stock solutions were made
at risk of impaired sexual development. This widespread com- containers, and dispensed
pound and other environmental endocrine disruptors may be a treated with ethanol suc
factor in global amphibian declines. ethanol. Water was change
every 72 h. Each treatm
I n the last 10 years, a great deal of attention has focused on the
global presence of endocrine-disrupting contaminants in the
animals per replicate (tota
experiments. All treatmen

62. Find a scientific article
and read the abstract.

63. Scientific findings should be
independently verifiable

64. Scientific findings should be
independently reproducible

65. AtrazineLovers.com
Atrazine.com

66. Theory

67. “...a unifying
explanation
for a broad range
of phenomena.’’

68. “A collection of
related hypotheses
that have been
tested many times
and not rejected...’’

69. “There is no absolute
truth in science, however,
only varying degrees
of uncertainty.’’

70. The
Science
of Life

71. 1.1 - 1.4, 1.9