10.1

Question 1

What happens in prophase of mitosis

Answer 1

replicated chromosome condense completely and independently and then the homologue pairs of replicated chromosome align closely before condensation is completed.

Question 2

What is a synapsis

Answer 2

the fusion of chromosome pairs at the start of meiosis

Question 3

What are sister chromatids

Answer 3

they have the same alleles as well as the same genes because they are identical copies of each other

Question 4

What are non sister homologs chromatids

Answer 4

they have the same gene at the same loci but for different alleles

Question 5

How does crossing over begin

Answer 5

Covalent bonds in the backbone of the DNA double helix at identical positions of the non-sister homologous chromatids, causing the helices to switch sides. The position of the chromatids are switched so that when the backbones are healed (ligated), a chromatid is covalently bonded to the non-sister chromatid.

Question 6

What is a chiasma (chiasmata)

Answer 6

a point of exchange between the two non-sister chromatids that creates an X shaped connection

Question 7

When do chiasmata remain

Answer 7

through metaphase I and they help bind the bivalent together as it is pulled to the metaphase plate

Question 8

What is the result of crossing over

Answer 8

the exchange of alleles between non-sister chromatids

Question 9

Where can crossing over occur

Answer 9

at almost any location along the tetrad (some have greater frequencies), leading to a nearly limitless number of possible combinations between non-sister homologous chromatids. Increasing genetic diversity present

Question 10

What does a tetrad consist of?

Answer 10

two pairs of sister chromatids that have synapsed

Question 11

What do genes found on different chromosomes show

Answer 11

independent assortment

Question 12

what does independent assortment mean

Answer 12

that the allele inherited for one gene does not influence which allele is inherited for a different gene

Question 13

What is geographic isolation

Answer 13

the separation of a population by a physical Marie that reduces or prevents the genetic flow

Question 14

What is allopatric speciation

Answer 14

when a new species develops as a result of pat of a population becoming geographically isolated from other populations

Question 15

What are types of physical barriers

Answer 15

things that keep populations in two separate places such as entire oceans or even a small strip of land between neighboring ponds. Sometimes after a storm, a small population may become isolated

Question 16

What does geographic isolation sometimes lead to

Answer 16

allopatric speciation

Question 17

In what conditions can populations at extreme of the geographic range no longer interbreed

Answer 17

when the species has a large enough Ange and slow enough gene flow

such as in salamandars

Question 18

What is behavioural isolation

Answer 18

any behaviour that acts to reduce or eliminate gene flow between portions of a population, such as variations in courtship song o location

Question 19

What is sympatric speciation

Answer 19

when a portion of a population develops into a new species whilst still living in the same geographic area as the ancestral population. sympatric speciation can occur due to behavioural temporal

Question 20

Wan does behavioral isolation occur

Answer 20

when genetically influences differences in behaviour have the effect of reduction or preventing mating between different portions of the population.

Question 21

What is an example of behavioral isolation

Answer 21

in mating song in male crickets has a preference for different variations in female tickets.

Question 22

What can behavioural isolation sometimes lead to

Answer 22

sympatric speciation

Question 23

What is temporal isolation

Answer 23

occurs when portions of a population are reproductively active at different times. Portions of the population may mate or flower at different times fo a day or during different seasons

Question 24

Temporal isolation

Answer 24

any shift in the timing fo a behaviour that acts to reduce or eliminate gene flow between portions of a population

Question 25

What is evolution

Answer 25

the cumulative change in heritable (genetic) characteristics of a species which requires changing allele frequencies

Question 26

What are the different ways in which speciation can occur due to the divergence of isolated populations

Answer 26

very gradually (gradualism) or abruptly (instantaneously) and there can be long periods of little change interspersed with shot periods of acid evolution (punctuated equilibrium).

Question 27

When does gradualism occur

Answer 27

When major changes are the cumulative product fo slow but continuous minor changes. In this model, mutation o immigration occasionally introduces new allesl to the gene pool which are then acted on by natural selection, becoming more common or disappearing

Question 28

What happens in each generation during gradualism

Answer 28

allelic shifts are subtle but tend to increase the frequency of any advantageous alleles. Individuals with the helpful trait survive and reproduce to pass on the alleles of the next generation. the cumulative changes in alleles become increasingly visible in the form of phenotypic changes in the population WW

Question 28

What happens in each generation during gradualism

Answer 28

allelic shifts are subtle but tend to increase the frequency of any advantageous alleles. Individuals with the helpful trait survive and reproduce to pass on the alleles of the next generation. the cumulative changes in alleles become increasingly visible in the form of phenotypic changes in the population

Question 28

What happens in each generation during gradualism

Answer 28

allelic shifts are subtle but tend to increase the frequency of any advantageous alleles. Individuals with the helpful trait survive and reproduce to pass on the alleles of the next generation. the cumulative changes in alleles become increasingly visible in the form of phenotypic changes in the population

Question 29

What type of process is gradualism

Answer 29

smooth and continuosu