HEREDITY: DNA and VARIATION in INHERITED CHARACTERISTICS
Enduring Understanding: Organisms reproduce, develop, have predictable life cycles, and pass on heritable traits to their offspring.
Biology Essential Questions: How are characteristics of one generation passed to the next?
How can individuals of the same species and even siblings have different characteristics?
Bio.3.5.2 Analyze the classification of
organisms according to their evolutionary
relationships (including: dichotomous keys
and phylogenetic trees).5A/H2
Bio.3.2.3 Explain how the environment can
influence the expression of genetic traits.
Bio.3.1.3 Explain how mutations in DNA that
result from interactions with the
environment (i.e. radiation and chemicals) or
new combinations in existing genes lead to
changes in function and phenotype.
5B/H5;5F/H5
Bio.3.2.2Predict the offspring ratios based on
a variety of inheritance patterns (including
dominance, co-dominance, incomplete
dominance, multiple alleles, and sex-linked
traits.. 5B/H2
Bio.3.1.2 Explain how DNA and
RNA code for proteins and
determine traits. 5B/H4
Bio.3.1.1 Explain the double-stranded,
complementary nature of DNA as related to
its function in the cell. (SFAA p. 61)
Bio.3.1.2 Explain how DNA and RNA code
for proteins and determine traits.
5B/H3;5C/H4
Bio.3.2.1 Explain the role of meiosis in sexual
reproduction and genetic variation. 5B/H2
Bio.1.1.3 Explain how instructions
in DNA lead to cell differentiation
and result in cells specialized to
perform specific functions in
multicellular organisms. 6B/H1
Grades 9-12
How is the genetic information stored within the molecules of a cell? LS3A
In all organisms, the instructions for specifying its characteristics are carried in DNA, a large polymer
formed from subunits of four kinds (A,G, C, and T). The chemical and structural properties of DNA
encode the genetic information that underlies heredity replicated by cellular mechanisms. Almost all
organisms use the same genetic code. One of the triumphs of modern biology is the demonstration that
DNA is the genetic material, and that DNA is transcribed into a “messenger” RNA, which is in turn
translated by the cellular machinery into a protein. Thus, a gene is a segment of DNA with a specific
nucleotide sequence that specifies the sequence of amino acids in a protein. In turn, proteins determine an
organism’s identifiable traits. Proteins have particular three-dimensional shape determined by their
amino acid sequence. Proteins have many different kinds of functions that depend on their specific
properties. There are different types of genetic mutations that can affect the structure and thus function of
proteins and ultimately the traits. All cells in an organism have the same genetic content, but the genes
used by the cell (expressed) may be regulated in different ways. Not all DNA codes for a protein;
some segments of DNA are involved in regulatory or structural functions, and some have no as-yet
known function.
(NAEP 2009)L12.8: Hereditary information is contained in genes, which are located in the chromosomes
of each cell. A human cell contains many thousands of different genes. One or many genes can determine
an inherited trait of an individual, and a single gene can influence more than one trait
How do variations occur in the genetic information stored within the molecules of a cell?LS3B
The information passed from parents to offspring is coded in the DNA molecules. Genes are
made of nucleotide sequences within the DNA molecule. DNA molecules make up the
chromosomes that together form each individual’s genome. DNA replication is tightly regulated to
prevent errors. But errors do occur. Usually genes on the same chromosome are inherited together.
However, occasionally during the process of meiosis chromosomes can swap sections (crossing over) and
create new genetic combinations. This creates more genetic variation. Gene variants – alleles – differ in
their nucleotide sequence, resulting in different or even missing proteins that affect an individual’s
phenotype. Dominant and recessive genetic relationships can be explained at the molecular level as a
consequence of the function and interaction of gene products. DNA mutations are the source of new
genetic variation. Some DNA sequences can vary between species while others do not; therefore, we
share some genes with other species. Environmental factors can also cause mutations in genes, and viable
mutations are inherited. Environmental factors also affect expression of traits, and hence affect the
probability of occurrences of traits in a population. Thus the variation and distribution of traits observed
depend on both genetic and environmental factors.
(NAEP 2009)L12.9: The genetic information encoded in DNA molecules provides instructions for
assembling protein molecules. Genes are segments of DNA molecules. Inserting, deleting, or substituting
DNA segments can alter genes. An altered gene may be passed on to every cell that develops from it. The
resulting features may help, harm, or have little or no effect on the offspring’s success in its environment.
L12.10: Sorting and recombination of genes in sexual reproduction results in a great variety of possible
gene combinations from the offspring of any two parents.
HEREDITY: DNA and VARIATION in INHERITED CHARACTERISTICS
Enduring Understanding: Organisms reproduce, develop, have predictable life cycles, and pass on heritable traits to their offspring.
6-8
Essential Questions: How are characteristics of one generation passed to the next?
How can individuals of the same species and even siblings have different characteristics?
Grades 6-8
To Biology
8.L.4.2 Explain the relationship
between genetic variation and an
organism’s ability to adapt to its
environment.
7.L.2.2 Infer patterns of heredity using information
from Punnett squares and pedigree analysis. 5B/M2c
(Patterns of heredity)
8.L.2.1 Summarize aspects of biotechnology
including:
• Specific genetic information available;
Careers; Economic benefits to North Carolina;
Ethical issues; Implications for agriculture
7.L.2.3 Explain the impact of the environment and
lifestyle choices on biological inheritance (to include
common genetic diseases) and survival. 6B/M5d
7.L.2.1 Explain why offspring that result from
sexual reproduction (fertilization and meiosis)
have greater variation than offspring that result
from asexual reproduction (budding and mitosis).
5B/M2c (Meiosis vs Mitosis)
7.L.2.1 Explain why offspring that result from
sexual reproduction (fertilization and meiosis)
have greater variation than offspring that result
from asexual reproduction (budding and mitosis).
5B/M2a,b (Fertilization vs. Budding)
7.L.2.1 Explain why offspring that result from
sexual reproduction (fertilization and meiosis)
have greater variation than offspring that result
from asexual reproduction (budding and mitosis).
5B/M1b (Sexual reproduction)
7.L.2.1 Explain why offspring that result from
sexual reproduction (fertilization and meiosis)
have greater variation than offspring that result
from asexual reproduction (budding and mitosis).
5B/M1a (Asexual reproduction)
Supporting Objective 6.P.2.1
6.P.2.1 Recognize that all matter is made up of
atoms and atoms of the same element are all alike,
but are different from the atoms of other elements.
(Structure & Classifications of Matter)
How are the inherited characteristics distributed to offspring? Ref LS3A
L8.9: Reproduction is a characteristic of all living systems; because no individual organism lives forever,
reproduction is essential to the continuation of every species. Some organisms reproduce asexually. Other
organisms reproduce sexually. (NAEP 2009)
AAAS5B/M1 In some kinds of organisms, all the genes come from a single parent. 5B/M1a; In organisms
that have two sexes, typically half of the genes come from each parent. 5B/M1b*; In sexual reproduction, a
single specialized cell from a female merges with a specialized cell from a male. 5B/M2a
Genes are located in the chromosomes of cells, with each chromosome pair containing two variants of each
of many distinct genes. Each distinct gene chiefly controls the production of a specific protein, which in turn
affects the traits of the individual (e.g., human skin color results from the actions of proteins that control the
production of the pigment melanin). Changes (mutations) to genes can result in changes to proteins, which
can affect the structures and functions of the organism and thereby change traits. Sexual reproduction
provides for transmission of genetic information to offspring through egg and sperm cells. These cells,
which contain only one chromosome of each parent’s chromosome pair, unite to form a new individual
(offspring). Thus offspring possess one instance of each parent’s chromosome pair (forming a new
chromosome pair). Variations of inherited traits between parent and offspring arise from genetic differences
that result from the subset of chromosomes (and therefore genes) inherited or (more rarely) from mutations.
(Boundary: The stress here is on the impact of gene transmission in reproduction, not the mechanism.)
How do variations occur as inherited characteristics are passed to offspring? Ref LS3B; AAAS5B/M2
The fertilized egg cell, carrying genetic information from each parent, multiplies to form the complete
organism. 5B/M2b*; The same genetic information is copied in each cell of the new organism. 5B/M2c;
New varieties of cultivated plants and domestic animals have resulted from selective breeding for particular
traits. 5B/M3 Cells divide to make new cells each with all the genetic information. Before cells divide, the
chromosome sets are duplicated and then two new cells are formed, each with two chromosomal sets
identical to those of the parent cell. In sexually reproducing organisms each parent contributes half the genes
(genetic information) to the new generation. The cells (except sex cells) in a human contain two copies of
each of 22 different chromosomes. In addition, there is a pair of chromosomes that determines sex: a female
contains two X chromosomes and a male contains one X and one Y chromosome. In sexually reproducing
organisms, chromosome sets are randomly assorted into gametes through the process of meiosis (one full set
into each sex cell). This process creates sex cells that have only one set of chromosomes. Different versions
of the same gene on a chromosome are called alleles. Each chromosome has one allele of each gene that it
carries. Individuals have two alleles of each gene, one from each parent. These versions may be identical or
differ from one another. An observed trait depends upon the set of alleles the offspring inherits from each
parent, as well as the specific relationship between the alleles (e.g., dominant, recessive, codominant, etc.).
Therefore, siblings (except for identical twins) will have different combinations of traits. In addition to
variations that arise from sexual reproduction, genetic information can sometimes change due to mutations.
Mutations in the genetic information are rare but can result in changes to the structure and function of
proteins. Some changes can be beneficial, others harmful, and some neutral to the organism in its
environment. Genes operate in a broader environmental context. Cells can respond to environmental changes
by altering specific constituents.
How are organisms of the same kind different from each other? How does this help them reproduce and
survive? NCDPI-Emphasis on Changing Environments NAEP 2009 FrameworkL8.10: The characteristics of organisms are influenced by heredity and environment. For some
characteristics, inheritance is more important; for other characteristics, interactions with the environment are
more important.
HEREDITY: DNA and VARIATION in INHERITED CHARACTERISTICS
Enduring Understanding: Organisms reproduce, develop, have predictable life cycles, and pass on heritable traits to their offspring.
3-5
Essential Questions: How are characteristics of one generation passed to the next?
How can individuals of the same species and even siblings have different characteristics?
To 6.L.1.1
Grades 3 – 5
5.L.3.2 Give examples of likenesses that are
inherited and some that are not.5B/E1,2
5.L.3.1 Explain why organisms differ from
or are similar to their parents based on the
characteristics of the organism. 5B/E1,2
NAEP L4.6
Supporting Objective 4.L.1.4
4.L.1.4 Explain how differences among
animals of the same population sometimes
give individuals an advantage in surviving
and reproducing in changing habitats.
5F/E1
NAEP L4.3, L4.4, L4.7
Supporting Objective 3.L.2.3
3.L.2.3 Summarize the distinct stages
of the life cycle of seed plants
NAEP L4.5
Why do offspring resemble their parents? LS3.A
Many characteristics of organisms are inherited from the parents. Other
characteristics result from an individual’s interaction with the environment. Many
characteristics involve both inheritance and the individual’s interaction with the
environment. Each parent contributes information that results in characteristics
(i.e., traits) in the offspring. Some likenesses between children and parents are
inherited. Other likenesses are learned. AAAS 5B/E1 For offspring to resemble
their parents, there must be a reliable way to transfer information from one
generation to the next. AAAS 5B/E2
How do offspring vary from their parents? LS3.B
Offspring acquire a mix of traits from their biological parents.
Different organisms vary in how they look and function because they have
different inherited information. Even within one kind of organism there is
variation in traits. Organisms vary in how they grow and function. For any given
trait there are variations. Different organisms may have different versions of the
trait. Organisms that are related may end up looking or behaving differently.
The environment also affects the traits that an organism develops—differences in
where they grow or in the food they consume may cause organisms that are
related to end up looking or behaving differently.
Supporting Objective 4.L.1.4
How are organisms of the same kind different from each other? How does this help
them reproduce and survive? NCDPI-Emphasis on Changing Environments
NAEP 2009 FrameworkL4.3: Organisms interact and are interdependent in various ways, including
providing food and shelter to one another. Organisms can survive only in
environments in which their needs are met. Some interactions are beneficial;
others are detrimental to the organism and other organisms.
L4.4: When the environment changes, some plants and animals survive and
reproduce; others die or move to new locations.
L4.5: Plants and animals have life cycles. Both plants and animals begin life and
develop into adults, reproduce, and eventually die. The details of this life cycle
are different for different organisms.
L4.6: Plants and animals closely resemble their parents.
L4.7: Different kinds of organisms have characteristics that enable them to
survive in different environments. Individuals of the same kind differ in their
characteristics, and sometimes the differences give individuals an advantage in
surviving and reproducing.
HEREDITY: DNA and VARIATION in INHERITED CHARACTERISTICS
Enduring Understanding: Organisms reproduce, develop, have predictable life cycles, and pass on heritable traits to their offspring.
K-2
Essential Questions: How are characteristics of one generation passed to the next?
How can individuals of the same species and even siblings have different characteristics?
To 5.L.3.1
2.L.2.1 Identify ways in which plants and animals
closely resemble their parents in observed
appearance and ways they are different. (5B/P2)
To 3.L.2.3
Grades K – 2
How are parents and offspring alike? LS3A
Living things possess characteristics that can be recognized and described as
either similar or different (e.g. number of legs, eye color, fur type, gender)
Offspring are very much, but not exactly, like their parents and like one
another. AAAS 5B/P2
2.l.2.1 Organisms have characteristics that can be similar or different.
Young animals are very much, but not exactly, like their parents and also
resemble other animals of the same kind. Plants also are very much, but not
exactly, like their parents and resemble other plants of the same kind.
To 4.L.1.4
2.L.2.2 Recognize that there is variation among
individuals that are related. (5B/P1, 5A/P1)
Are all individuals of one kind the same? LS3B
2.L.2.2 Individuals of the same kind of plant or animal are recognizable as
similar but can also vary in many ways.
There is variation among individuals of one kind within a population. AAAS
5B/P1
Supporting Objective 2.L.1.1
Summarize the life cycle of animals
including: birth, developing into an
adult, reproducing, aging and death.
Supporting Objective 2.L.1.1
Why do offspring resemble their parents?
The offspring of some plants and animals do not resemble the parents. Similarities
between parents and their offspring become more apparent as their life cycle continues
(i.e., caterpillars become butterflies). All plants and animals go through a life cycle of
birth, growth, development, reproduction, and death. This cycle is predictable and
describable, but differs from organism to organism.
(Delaware Department of Education-LFS7)
Mechanism of inheritance
Sexual reproduction
Variation
Cells and development