HS - LS3.B (B) - Genetics - FINAL (AuMy 4/21/2014)

Module: Genetics

DCI: LS3.B (B) 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 depends on both genetic and environmental factors.

PE: HS-LS3-2 Make and defend a claim based on evidence that inheritable genetic variations may result from: (1) new genetic combinations through meiosis, (2) viable errors occurring during replication, and/or (3) mutations caused by environmental factors.

PE: HS-LS3-3 Apply concepts of statistics and probability to explain the variation and distribution of expressed traits in a population.

[Clarification Statement: Emphasis is on the use of mathematics to describe the probability of traits as it relates to genetic and environmental factors in the expression of traits.] [Assessment Boundary: Assessment does not include Hardy-Weinberg calculations.]

The ideas are: 

- environmental factors can affect the expression of traits

- environmental factors affect the probability of occurrences of traits in a population

- the variation and distribution of traits depends on both genetic factors and environmental factors

So we can establish, through some sort of evidence, that inherited variation was the result of genetic processes OR environmental factors (mutations).  In order to do this, we can provide information on a population with varied traits, and link that to one particular cause or another.  For example, in a population of fish, there may be a variety of traits and assuming that the fish all lived under the same environmental conditions, then it's assumable that the differences are a direct result of genetic information. The phrase 'use of mathematics' implies that it is ok to ask questions with Punnett Squares. 

Possible Question Starters:

"Which of the following correctly describes how meiosis contributes to populations with a variety of traits?"

"The gene for tallness (T) in a pea plant is dominant over the gene for shortness (t).  In a cross between two heterozygous parent pea plants, we can predict that what percentage of the offspring will be tall?"