Download level two biology: genetic variation

LEVEL TWO BIOLOGY: GENETIC VARIATION
•Sources of variation – meiosis and mutations
•Alleles and populations
•Inheritance – crosses and pedigree charts
Sources of Variation – Meiosis and Mutations:
I can define variation by using terms including: ‘alleles’ and
‘population’.
I can explain the difference between a gene and an allele.
I can show that I understand how meiosis increases variation by
describing and drawing diagrams of each of the following
processes and discussing how each process leads to genetic
variation:
Recombination (or crossing-over)
Independent assortment
Segregation
I can show that I understand how mutations increase genetic
variation by defining the term ‘mutation’ and how mutations can
lead to new genotypes and phenotypes.
I can show that I understand the difference between gametic and
somatic mutations by explaining where they occur and which
type of mutation will affect future offspring.
I can show that I understand what a ‘point mutation’ is by:
Defining the term ‘point mutation’ in terms of the order of bases in a gene.
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Naming and describing types of point mutations (insertion, elimination and substitution).
Writing examples of insertion, elimination and substitution mutations (by writing out a sequence of bases – A, T, C and G).
Defining the term ‘frame shift’ and describing which types of point mutations cause a frame shift.
Comparing the effects of mutations that cause a frame shift with mutations that do not.
I can show that I understand why some mutations become
integrated into a population while others do not by discussing the
fitness of mutations (i.e. harmful, lethal, silent or beneficial).
Alleles and Populations:
I can define the term ‘gene pool’.
I can define the term ‘allele frequency’ by linking alleles to the
gene pool of a population.
I can show that I understand how allele frequencies in a gene
pool can change by describing and discussing:
Genetic drift
Bottleneck effect
Founder effect
Migration
I can give a concise definition of fitness by using terms including:
‘survive’ and ‘reproduce’.
I can show that I understand the process of natural selection by
explaining this process in terms of ‘survival of the fittest’.
I can link alleles and evolution by discussing how natural
selection causes evolution by selecting for alleles that are
advantageous in an organism’s environment.
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Inheritance – Crosses and Cedigree Charts:
I can show that I understand how the genes of parents combine
to determine the traits of the offspring by:
Drawing and completing a monohybrid cross.
Drawing and completing a dihybrid cross.
Interpreting monohybrid and dihybrid crosses to write phenotypic and genotypic ratios of offspring.
Defining the following terms and adapting monohybrid crosses to account for their presence:
Complete dominance
Incomplete dominance
Codominance
Multiple alleles
I can explain what linked genes are.
I can show that I understand the significance of linked genes by
explaining the connection between recombination and linkage
and discussing how this may affect a theoretical dihybrid cross.
I can show that I understand what sex-linked genes are by
discussing how they occur in terms of X and Y chromosomes.
I can discuss pure breeding and how to carry out a test cross to
determine the genotype of an organism.
I can interpret and draw information from pedigree charts.
I can discuss whether it is possible to determine the genotypes of
individuals from a particular pedigree chart and give reasons for
my interpretations.
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