1.6 Flashcards
What is the focus of genetics in relation to evolution?
Finding an explanation for the inheritance of traits (Heredity)
Why is variation within a population important?
It is key for a species to be able to evolve and ultimately survive
What was a major limitation of Darwin’s Theory?
He could not explain how traits were transferred to offspring without being blended out
What did Mendel contribute to the understanding of genetics?
He explained that a given phenotype is determined by a certain genotype and introduced the concept of alleles
What is an example of alleles Mendel studied?
One allele codes for yellow seed coat color and another codes for green
What unexpected result did Mendel find when crossing pea plants?
All first generation plants produced smooth round peas
What was the phenotypic ratio in Mendel’s second generation of pea plants?
3 round : 1 wrinkled
How did Mendel explain the reappearance of the wrinkled trait?
Traits were not blended but were preserved
What is the dominant allele for smooth round peas?
R (dominant allele for smooth round pea)
What is the recessive allele for wrinkled peas?
r (recessive allele for wrinkled pea)
What organisms have been primarily studied for human genetics?
Pea plants and fruit flies (Drosophila)
How can population sampling be used in genetics?
To estimate the frequency of a given phenotype (phenotypic ratios)
What percentage of the population in Kelowna can roll their tongue if 1300 out of 2000 can?
65%
What happens to allelic frequencies during a state of genetic equilibrium?
They remain constant from generation to generation
What can upset the state of genetic equilibrium?
External pressure, mutation, or genetic drift
What effect do external pressures have on a population?
They can cause the allelic frequencies in a gene pool to change and therefore the population will evolve
Fill in the blank: Mendel proposed that in some cases a certain allele for a given gene could be ______ to another allele for the same gene.
[dominant]
True or False: All traits are blended in offspring according to Mendel’s findings.
False
