Chapter 10 Biology

Define crossing over. When does it occur?

Crossing over is the exchange of DNA material between nonsister homologous chromatids

When do chromosomes replicate?

In the S phase of Interphase

What does crossing over produce?

Crossing over produces new combinations of alleles on the chromosomes of the haploid cells

What can chiasmata formation result in?

Chiasmata formation between non-sister chromatids can result in an exchange of alleles

When do homologous chromosomes separate?

In Meiosis 1 (Anaphase 1)

When do sister chromatids separate?

In Meiosis 2 (Anaphase 2)

What causes Independent Assortment?

Independent assortment of genes is due to the random orientation of homologous chromosomes in meiosis 1

When are gene loci said to be linked?

Gene loci are said to be linked if on the same chromosome

How do unlinked genes segregate?

Unlinked genes segregate independently as a result of meiosis

Variation can be 2 things

Discrete or continuous

What do the phenotypes of polygenic characteristics tend to show?

The phenotypes of polygenic characteristics tend to show continuous variation

What are chi-squared tests used to determine?

Chi-squared tests are used to determine whether the difference between an observed and expected frequency distribution is statistically significant

What does a gene pool consist of?

A gene pool consists of all the genes and their different alleles present in an interbreeding population

What does evolution require?

Evolution requires that allele frequencies change with time in populations.

What are the types of reproductive isolation?

Behavioral, geographic, temporal

Speciation due to divergence of isolated populations can be

Gradual

Speciation can also occur

Abruptly