B. NEUREITHER
Science Content Standards and Benchmarks for Heredity
Middle School
Describe how the characteristics of living things are passed on through
generations.
•
•
Sex cells – egg, sperm
Chromosome, gene, heredity information
Describe how heredity and environment may influence/determine
characteristics of an organism.
•
Traits – inherited vs. acquired
High School
Explain how characteristics of living things are passed on from generation to
generation.
•
•
•
Traits – dominant and recessive
Genetic material – gene pair
Inheritance of human genetic disease/disorder
Describe how genetic material is passed from parent to young during sexual
and asexual reproduction.
•
•
Cell division – mitosis, meiosis
DNA replication – chromosomes double before division
Explain how new traits may arise in individuals through changes in genetic
material (DNA).
•
•
•
Genetic changes – variation, new gene combinations, mutation forming new alleles
Sources of mutation – radiation, chemicals, etc. (mother nature)
You need a complete set of genes to make a complete set of proteins to build the cell
structures and control the reactions needed for life
2005 VIPP Biology
B. NEUREITHER
Big Ideas in Genetics
• Our genes and our environment control our physical traits.
• Every cell in our body has a complete set of chromosomes containing the
genes for our inherited traits.
• Some inherited traits are dominant, some are recessive, and some are
neither. Dominant traits can hide recessive traits when an organism inherits
one of each.
• Genes cause the formation of proteins that determine our physical
characteristics.
• Inherited traits are passed on from generation to generation when
chromosomes carrying genes are passed from parent to offspring in sex
cells.
• We inherit genes (and chromosomes) in pairs, one from our mother and one
from our father.
• We need a complete set of genes and chromosomes to make the proteins we
need to function normally.
• If a mutation occurs in a gene (changing the DNA sequence) it may cause a
change in the protein the gene produces which may affect your survival and
ability to reproduce and pass on your genetic material to the next generation.
2005 VIPP Biology
B. NEUREITHER
Naïve Conceptions in Genetics and Evolution
•
Daughters inherit most of their characteristics from their mothers. Boys
inherit most of their characteristics from their fathers.
•
Male characteristics are stronger when blended with female characteristics.
•
Students do not understand the relationship between DNA, genes, and
chromosomes.
•
Students can apply chance and probability to assigned genetics problems,
but not to human situations in families.
•
Sexual reproduction occurs in animals but not in plants.
•
Students do not distinguish between sexual and asexual reproduction.
•
Asexual reproduction produces weak offspring. Sexual reproduction
produces superior offspring.
•
Transmitted characteristics are acquired during the lifetime of the animal.
•
Individuals can adapt to a changing environment. These adaptations are
heritable.
•
Students have difficulty relating an individual’s adaptation to environment
with changes in species phenotypes over long period of time due to
selection. Instead, they see it as the individual organism changing in
response to the environment so they can survive.
•
Variation occurs, but it is in response to environmental conditions rather
than due to inheritance (i.e. Sexual reproduction).
2005 VIPP Biology
B. NEUREITHER
Instructional Strategies
•
Students should identify a wide range of examples of acquired and inherited
human traits. (Look for pattern and explanation)
•
Students need to study genetics from big to little. First understanding the
chromosomal basis of inheritance, and the randomness of the transmission of
traits.
•
Working with human and animal traits, they should trace the inheritance of
traits through model families and determine the probabilities of trait
inheritance.
•
Students should carefully model the relationships between traits,
chromosomes, genes, and DNA.
•
Students should build models that demonstrate their understanding of the
mechanisms of meiosis.
•
Students should relate survival under stress and pre-existing traits.
•
Students need to see actual examples of populations of organisms that have
changed due to selection favoring particular traits.
•
3R’s – relevant, rigorous, but reachable
Taken from the MSTA newsletter, Spring 1998. , Making Sense of Secondary Science, Driver, et
al, 1994, and my experiences 1972-present.
2005 VIPP Biology