Patterns Of Inheritance Flashcards

Question

What is the chi-squared test

Answer 1

A statistical test to find out whether the difference between observed and expected data is due to change or a real effect Can be used to compared expected phenotypic ratios with observed ratios

Answer 2

The formula results in a number which is then compared to a critical value (for the corresponding degrees of freedom). If the number is greater than or equal to the critical value, we conclude that there is no significant difference and the results occurred due to chance

Answer 3

Discontinuous variation = characteristic determined by one gene (monogenic inheritance) Continuous variation = characteristic determined by more than one gene (polygenic inheritance)

Answer 4

Occurs when environmental conditions stay the same, Individuals closest to the mean are favoured and any new characteristics are selected against Results in low diversity

Answer 5

Occurs when environmental conditions change. Individuals with phenotypes suited to the new conditions will survive and pass on their genes. Overtime the mean of the population will move towards these characteristics

Answer 6

A change in a population's allele frequencies that occur due to chance rather than selective pressures. In other words, it is caused by 'sampling error' during reproduction

Answer 7

Where a catastrophic event dramatically reduces the size of a population, therefore reducing the variety of alleles in the gene pool and causing large changes in allele frequencies

Answer 8

When a small numer of individuals become isolated, forming a new population with a limited gene pool, with allele frequencies not reflective of the original population

Answer 9

Allows us to estimate the frequency of the allels within a population as well as if allele frequency is changing overtime

Answer 10

The frequencies of each allele for a characteristic must add up to 1.0. The equation is therefore **p + q = 1** Where p= frequency of the dominant allele and q= frequency of the recessive allele

Answer 11

The frequencies of each genotype for a characteristic must add up to 1.0 The equation therefore is **p^2 + 2pq + q^2** Where p^2 = frequency of homozygous dominant, 2pq= frequency of heterozygous and q^2 is the frequency of homozygous recessive

Answer 12

Where a population is split and isolated, there are different selection pressures on the two groups. If the genetic makeup changes to the extent the two species can no longer interbreed, then they have become separate species

Answer 13

Speciation resulting from a physical barrier e.g. river, mountain range. The environments occupied by the two groups are different, and therefore different alleles are favoured

Answer 14

Speciation resulting from a non-physical barrier - e.g. a mutation that no longer allows two organisms to produce fertile offspring. Any changes in anatomy or behaviour may also prevent breeding

Answer 15

Humans choose specific organisms to breed together in order to produce a desired characteristic in the offspring

Answer 16

Plants = seeds used from plants which produce larger fruit and vegetables Animals = cows with higher milk yield are chosen and selectively bred

Answer 17

Allows any traits that were accidentally bred out to be reintroduced, or to revert back to a point before any negative traits were introduced

Answer 18

Anatomical issues in animals e.g. respiratory issues in pugs and other short snouted dogs Higher susceptibility to disease in both plants and animals