Content Benchmark L.8.A.4
Students know some characteristics of an organism are the result of a combination of interaction
with the environment and genetic information. E/S
All organisms have characteristics that make them unique. Even organisms that are identical to
each other genetically are not necessarily identical in every way. This is because conditions and
elements of the environment affect the expression of some genetic characteristics. Organisms are
shaped by a complex interaction of environmental influences and genetics. Environmental
influences include nutrition, habitat, amount of exercise, chemical composition of the organism,
experience, learning, and other factors.
Genetic Influences
Through heredity, we inherit characteristics from our parents. Inherited characteristics are
passed from parents to offspring through DNA. The pieces of DNA that code for specific traits
are called genes.
For detailed information on the role genetics on heredity, see MS TIPS Benchmark L.8.A.1
To read more about genes, and how characteristics are determined by both genetics and by the
environment, see http://kids.niehs.nih.gov/genes/page2.htm
Environmental Influences and Multifactorial Traits
Inheritance alone does not determine everything about us. For example, good care and nutrition
may help us to grow bigger and taller than either of our parents. An example of this height
differential was documented in Japanese immigrants to the United States in the 1930s. Second
generation Japanese immigrants were taller than their counterparts in Japan. The growth
differential was primarily due to migration into an area which provided an improvement in diet
and healthcare.
To read more about this and other genetic mechanisms, see excerpt in Patterns of Human
Growth, second edition, by Barry Bogin. A summary of the Japanese immigrant height study is
found at the following link
http://books.google.com/books?id=ScfPjwF3BngC&pg=PA298&lpg=PA298&dq=japanese+im
migrant+children+taller&source=web&ots=gGuUB0ZU9T&sig=S2f0VaXIQwjvKsML1B7LjFp
CIuY&hl=en
Figure 1: Inheriting Features from Parents.
(From: http://kids.niehs.nih.gov/genes/page2.htm)
Many traits are “multifactorial.” This means that several factors contribute to the expression of a
trait. These factors are both genetic and environmental. To read more about multifactorial traits,
see
http://www.aboutkidshealth.ca/HowTheBodyWorks/MultifactorialTraits.aspx?articleID=10213&
categoryID=XG-nh7-02
Table 1. Inherited Human Traits Influenced by the Environment
(From http://www.pbs.org/wgbh/nova/teachers/viewing/3313_03_nsn.html)
Condition
Genetic Factors
Environmental Factors
Type 1
Diabetes
Primarily a genetic condition related to the ability
to produce insulin
Influenced by environmental factors such as toxins taken
into the body that can damage the pancreas
Type 2
Diabetes
Complicated interplay of genetics and the
environment
Lifestyle factors such as diet and obesity may trigger
some of the genetic elements that cause Type 2 diabetes
Skin Cancer
Influenced by genetic factors, such as the skin’s
melanin levels and ability to repair damaged DNA
Exposure to high levels of ultraviolet radiation can
promote its development
Height
Mainly determined by genes determining bone
length and bone mineral mass
Adequacy of nutrition plays a role
Weight
Genetic factors play a role in appetite, nutritional
intake, and metabolism
Influenced by nutrition and physical activity
Muscularity
Genetics contribute to muscle fiber composition
and size, and how skeletal muscle uses oxygen
Physical training influences oxygen utilization and muscle
fiber size and volume
Table 1 above is designed to be included with an activity that involves viewing the video entitled
NOVA scienceNOW: Obesity. This chart can be useful in discussions that can help students
understand the interactions between genetics and environment.
Disease investigation is one particular area of study that can help students understand the
interactions between inherited traits and the environment. There are some diseases which result
solely from genetic factors regardless of the environment. However, many diseases such as
cancers, asthma, and Type II diabetes, result when genetics and the environment interact. A
person may be genetically predisposed for diabetes, but because their diet is controlled, they may
never suffer from that disease.
To learn more about how environment and genetics interact to influence health, see National
Institutes of Health’s Fact Sheet: Genes, Behavior, the Environment, and Health at
http://www.nih.gov/about/researchresultsforthepublic/GenesandBehavior.pdf
A similar paper, Gene-Environment Interaction Fact Sheet from the Center for Disease Control
can be found at
http://www.cdc.gov/genomics/training/file/print/perspectives/geneenviro.pdf
New discoveries about the human genome are made everyday. It is now known that many
diseases and behaviors are linked to genes. For example, a correlation exists between family
history, genetics, and addictions such as alcoholism. Several genes have been linked to addiction.
However, just because a person may have one of these genes, he or she will not necessarily
become addicted to alcohol or drugs. Social and environmental conditions contribute major risks
for these addictions.
To learn more about genetics and addiction, see
http://learn.genetics.utah.edu/units/addiction/genetics/
Learned and Innate Behaviors
The influence of environment on behavior can be observed in animals, where behaviors are
either innate or learned. An innate behavior is one that exists from birth or is inborn. Innate
characteristics are inherited and are present at birth. Innate behavior is pre-programmed. Some
examples of innate knowledge or behavior are: hatching from an egg, suckling, weaving a web,
migration, and hibernation.
To learn more about innate behavior, see
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/I/InnateBehavior.html
Learned behavior can be altered as a result of experience and or environment. Sometimes the
difference between innate behavior and learned behavior is referred to as nature versus nurture.
Nature refers to the characteristics that an organism is born with. Nurture refers to behavior
learned through personal experience.
To learn more about learned behavior, see
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/L/LearnedBehavior.html
Genetic Changes
Genetic changes occur randomly. Sometimes the changes make an organism more suitable to a
given environment. If a genetic change enables an organism to survive better, that particular
organism will survive and pass on its traits. For more information on mutations and their possible
effects, see MS TIPS Benchmark L.8.A.2. Over time, a population of organisms may change.
This is called evolution and is explored within MS TIPS Benchmark L.8.D.3.
Twins, Clones and Epigenetics
Clones and identical twins are not really identical. Even though clones and identical twins arise
from exactly the same DNA, the environment and other factors will affect expression of traits.
To learn more about cloning, see
http://www.ornl.gov/sci/techresources/Human_Genome/elsi/cloning.shtml
Much research has been done on twins to investigate the influence of genetics and of
environment on expression of traits, especially behavioral traits. These studies often conclude
that both environment and DNA interact in the expression of traits.
To read more about several twin studies, reference the following university-based twin research
programs at
http://ibgwww.colorado.edu/twinsites.html, and
http://www-rcf.usc.edu/~lbaker/twins.html.
Physical characteristics of twins provide excellent examples of how the environment affects the
expression of traits. Even though identical twins arose from identical DNA, many characteristics
are different. For example, the fingerprints of identical twins, although similar, are not identical.
Figure 2. Comparing Fingerprints.
For a brief explanation as to why the fingerprints may be different, see
http://genetics.gsk.com/kids/factoids_kids/fact04.htm
The fingerprints a and c above are from twins. Notice that although very similar,
they are not identical. The fingerprint in b is also similar, but unrelated to a and c.
(From http://pagesperso-orange.fr/fingerchip/biometrics/types/fingerprint.htm)
In addition to the environment affecting the expression of genes, some genes can be activated or
inactivated. This is called epigenetics (middle school students should not be taught about
epigenetics other than showing and explaining a few examples of non-identical clones). For
example, the coloring of calico cats is a result of genes that code for orange and genes that code
for black fur. In each body cell, the orange and black genes are randomly turned on or off,
resulting in a unique pattern of color for each individual. Observe the picture of the two cats in
Figure 3. CC is a clone of Rainbow but the two cats do not look the same due to the different
patterns of color. No two organisms, even clones, will be exactly the same due to the interaction
of genes with the environment.
Figure 3. Cloned kitten.
(From: http://learn.genetics.utah.edu/units/cloning/cloningmyths/)
To learn more about epigenetics, see
http://www.pbs.org/wgbh/nova/sciencenow/3411/02.html
Content Benchmark L.8.A.4
Students know some characteristics of an organism are the result of a combination of interaction
with the environment and genetic information. E/S
Common misconceptions associated with this benchmark
1. Some students believe that acquired characteristics can be inherited.
An 18th century French naturalist, Jean-Baptiste Lamark (as well as many scientists and
philosophers before him) was a proponent of this theory of evolution that states that acquired
traits can be inherited. The belief was that some characteristics of an organism changed over
the organism’s lifetime, and these acquired traits would be passed on to offspring. The
classic example often cited in student texts regards the giraffe’s neck. The theory of
inheritance by acquired traits states that a giraffe had to stretch its neck to reach leaves in the
highest tree branches. Because of the continual stretching, a giraffe’s neck grew longer, and
this longer neck characteristic was passed to the giraffe’s offspring.
To read more about Lamark, see http://www.ucmp.berkeley.edu/history/lamarck.html
The modern understanding of evolution is that traits are passed from generation to generation
via the DNA (genome) of reproductive cells. Adaptations of a body part due to use or nonuse do not cause changes in these reproductive cells. Acquired traits do not affect the
genome of an organism and it is the genome that is passed to offspring by the parent
organism.
For a detailed explanation of the modern theory of evolution see
http://evolution.berkeley.edu/evosite/evo101/IIntro.shtml
2. Some students believe that variation between species is the result of a change in an
organism’s environment, not due to inheritance.
Bears live in many different environments around the world. Bears with white fur, such as
polar bears live where there is a lot of snow and ice. Black and brown bears live in forested
areas. These particular characteristics have enabled bears to survive in particular
environments. The bears that had genetic characteristics that helped them survive where able
to live and reproduce. The genetic characteristics which enabled them to survive were
passed on to their offspring. The characteristics which helped a particular organism to
survive better than another were caused by random changes in the DNA, not changes in the
characteristics themselves. A polar bear’s fur will not turn brown if they are moved from the
snowy regions to a non snowy region. Nor will a brown bear turn white if moved to a snowy
region. Animals, such as these bears, have adaptations, camouflage for example, that enable
them to survive in particular environments. The organisms that survive are able to reproduce
and pass on their traits to their offspring.
To read more about animal camouflage, see
http://ellerbruch.nmu.edu/classes/cs255w03/cs255students/nsovey/P6/P6.html
To learn some interesting middle school level facts about animals and color, see
http://www.highlightskids.com/Science/Stories/SS1000_animalColors.asp
To watch a video clip of a classroom in which the teacher uses plants to help students explore
the variation and discuss adaptation, see
http://www.hsdvl.org/video.php?record_serial=272
3. Some students believe that use or non-use of an organ will affect how that organ works
in future generations.
This misconception has lead to some interesting science-fiction type scenarios. Some
examples of this misconception are suggestions such as the human brain will become bigger
and bigger as we learn to use it more, or humans will soon be born with no appendix and no
wisdom teeth because they are often removed and are not needed. Dr. Barry Starr, a
geneticist at Stanford University wrote a short, easy to read article discussing the use – non
use misconception.
Dr. Starr’s article can be accessed at
http://www.thetech.org/genetics/ask.php?id=193 .
Content Benchmark L.8.A.4
Students know some characteristics of an organism are the result of a combination of interaction
with the environment and genetic information. E/S
Sample Test Questions
Questions and Answers to follow on a separate document
Content Benchmark L.8.A.4
Students know some characteristics of an organism are the result of a combination of interaction
with the environment and genetic information. E/S
Answers to Sample Test Questions
Questions and Answers to follow on a separate document
Content Benchmark L.8.A.4
Students know some characteristics of an organism are the result of a combination of interaction
with the environment and genetic information. E/S
Intervention Strategies and Resources
The following is a list of intervention strategies and resources that will facilitate student
understanding of this benchmark.
1. NOVA scienceNOW: Obesity
This website contains a video and several related activities which can be used to learn about
the interactions between genetics and the environmental influences on obesity. The site has
pre and post viewing activities, and the 12 minute video can be watched online. Although
the video and the activities deal predominately with obesity they can be incorporated as a
relevant lesson to help students understand the connections between genetics and
environment. Some of the activities may be difficult for middle school students, but the postviewing activity on “Nature vs. Nurture” is especially appropriate for use when studying this
benchmark.
The video and activities can be accessed at
http://www.pbs.org/wgbh/nova/sciencenow/3313/03.html
2. Pets: Oh Behave
This lesson which takes students through a series of activities related to training pets can help
students develop an understanding of how innate behaviors, learned behaviors and the
environment all play a role in determining behavior.
The site can be accesses at
http://www.sciencenetlinks.com/lessons.cfm?BenchmarkID=6&DocID=288
3. A Nature and Nurture Walk in Mendel Park
This is a short interactive activity from the American Museum of Natural History. In the online activity, students solve a riddle by answering questions about whether specific
characteristics are due to nature or nurture or both.
To access this activity visit
http://www.amnh.org/ology/genetics/naturewalk/index.html
4. Exploring Learned and Innate Behavior
This activity allows students to explore the differences between learned and innate behavior
among humans and monkeys. Students read articles and visit websites and then answer
questions about various ways humans and monkeys communicate, use tools, etc. Throughout
the activity, students are prompted to think about what is innate and what is learned behavior.
The activity can be accessed at
http://www.sciencenetlinks.com/lessons.cfm?BenchmarkID=6&DocID=461