Topic 7 Inheritance Flashcards by Keira Williams

What is a genotype

The genetic constitution of an organism

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What is the phenotype

The expression of the genes and it’s interaction with the environment

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What is homozygous

A pair of homologous chromosomes carrying the same alleles for a single gene

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What is heterozygous

A pair of homologous chromosomes carrying 2 different alleles for a single gene

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What is a recessive allele

An allele only expressed if no dominant allele is present

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What is a dominant allele

An allele that will always be expressed in the phenotype

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What does co dominant mean

Both alleles are equally dominant and expressed in the phenotype

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What is sex linkage

A gene whose locus is on the X chromosome

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What is autosomal linkage

Genes that are located on the same chromosome (not sex chromosome)

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What is epistsis

When one gene modified or masks the expression of a different gene at a different locus

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What is mono hybrid

Genetic inheritance cross of characteristics determined by one gene

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What is dihybrid

Genetic inheritance cross for a characteristic determined by 2 genes

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How would you write a sex linkage genetic diagram

Chromosome and then the allele

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What type of allele is cystic fibrosis caused by

Recessive

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If 2 carriers of CF reproduce what is the probability they have a girl with cystic fibrosis

So the parental genotypes would be Ff and Ff so there would be a 25% chance of child with CF but if it’s a girl there’s 50% chance so you’d do 25% x 50% = 12.5%

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What is the ratio of a dihybrid cross with 2 heterozygous parents

9:3:3:1

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If autosomal linkage has occurred what is the ratio for dihybrid cross

3:1

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What is chi squared

The statistic to investigate differences between frequencies

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What is the null hypothesis

There is no significant difference between the expected and observed frequency of …

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What is a gene pool

All the alleles of all the genes within a population at one time

What is a population

All the individuals if one species in one area at one time

What is allele frequency

The proportion of an allele within the gene pool

What is the equation for hardy Weinberg

P2 + 2pq + q2 =1

P= dominant allele
q = recessive
2pq = heterozygous
P2 = homozygous dominant
q2 = homozygous recessive

What is the 2nd equation for hardy Weinberg

P+q=1

What are the main sources of genetic variation(3)

Mutations, meiosis and random fertilisation

What is disruptive selection

When individuals contain alleles coding for either extreme trait are more likely to survive and pass on their alleles

What is speciation

A creation of a new species

how does speciation occur

When original propulsion becomes reproductively isolated and cannot breed together

What is allopatric speciation

Geographic isolation

What is sympatric speciation

Changes in the reproductive mechanisms

Explain how sympatric speciation occurs

1. Random mutation impacts reproductive behaviour e.g different courtship or different fertility times 2. Due to this the individuals will not reproduce so there will be no gene flow between the 2 groups within the population 3. Causing reproductive isolation they will accumulate different mutations so they cannot interbreed

What is genetic drift

Change in allele frequency within a population between generations

What is a population

Group of organisms of the same species living in the same habitat

What is a habitat

Part of an ecosystem in which particular organisms live

What is a community

All the populations of different species in the same area at the same time

What is an ecosystem

A community and the non living components of an environment

What is a niche

Organisms role in an ecosystem including their position on the food web and habitat

What is a carrying capacity

The maximum population size an ecosystem can support

Give 3 examples of abiotic factors

Carbon dioxide conc, light intensity and Ph

Give 2 examples of biotic factors

Competition and predication

What is interspecfic competition

Members of different species are in competition for the same recources such as food or water

What is intraspecific competition

Members of the SAME species are in competition e.g a mate

When would you sample using a quadrat

When is it a slow moving organism

What would you use for sampling with motile organisms

Mark - release - recapture

Explain the method of the mark-recapture- release

1. Initial sample of population is captured 2. Individual are marked harmlessly 3. Marked individuals released and left for period of time allowed to randomly disperse 4. Second sample captured 4. Total number of captured in the second sample and number recaptured with marks recorded 5. Size of population is then estimated on principle that proportion marker in second sample = proportion of marked individuals as population as a whole

What is the calculation for the estimated total population

Number of organisms initially caught x number of organisms caught in 2nd sample / number of marked organisms recaptured

What is succession

Change in ecological community over time

What is primary succession

Starts with a pioneer species colonising a bare rock or sand E.g lichen adapted to survive harsh abiotic factors and from their death the abiotic factors become less harsh and from a thin layer of soil called humus

What is secondary succession

Disrupted and plants are destroyed