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Module 6 > Patterns Of Inheritance > Flashcards

Patterns Of Inheritance Flashcards

1
Q

What is continuous variation

A
  • polygenic / controlled by environment
    Wheee the individuals vary within a range: no distinct categories
    Data = quantitative e.g. height
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2
Q

What is discontinuous variation

A
  • monogenic & little environmental influence
    2 or more distinct categories (& u only fall into one)
    E.g. type A, B, AB, O
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3
Q

Examples of factors influenced by genetic & environmental factors (therefore continuous?)

A
  • diet
  • chlorosis
  • etiolation
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4
Q

What is chlorosis (yellowed leaves due to less chlorophyll production) due to

A
  • lack of light,therefore low chlorophyll production to conserve resources
  • mineral deficiencies e.g. iron needed as enzyme cofactor to make chlorophyll
  • virus infections
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5
Q

How can animal diet be linked to mass and obesity etc

A

Obesity can be due to genes e.g. mutations on chromosomes = altered fat deposition
Bit mainly due to environmental factors e.g. how much u eat, workout, disease

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6
Q

What is etiolation

A

When plants are grown in the dark and may develop long stems with small, curled leaves even though genetically, should grow normally

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7
Q

How sexual reproduction can lead to genetic variation

A
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8
Q

5 diff types of genetic diagrams

A
  • monogenic inheritance
  • dihybrid inheritance
  • multiple alleles
  • sex linkage
  • co-dominance
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9
Q

What’s monogenic inheritance

A
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10
Q

Dihybrid inheritance (of two genes) diagram

A
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11
Q

Multiple Alleles diagram

A
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12
Q

Multiple Alleles diagram

A
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13
Q

Genetic diagram for sex linkage

A
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14
Q

Codominance diagram

A
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15
Q

Difference between Co-dominance & Incomplete dominance

A

Co-dominance = both alleles have the effect so e.g. a red and a white coat come together to give a pink coat

Incomplete dominance = a mixture of the alleles in the genotype e.g. than the pink coat, it would be red or white stripes or spots on the coat

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16
Q

How are phenotypic ratios important

A
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17
Q

What is autosomal linkage

A

If 2 genes are found on the same (nonsex chromosome)
- the closer the two genes are, the likelier they both are of being inherited as one unit

Occurs differently depending on the gene loci / location as they affect that the two genes / alleles & how they may be inherited

18
Q

What is epistasis

A
19
Q

What are the factors that affect the evolution of a species

A
  • founder effect
  • genetic drift
  • genetic bottleneck
  • selection pressures
20
Q

What are the 2 types of selection pressures

A

Directional selection
Stabilising selection

21
Q

What is stabilising selection

A

Natural selection that keeps alleles frequencies = constant (unless a change in environment)

22
Q

What is directional selection

A

Natural selection that produces a gradual change in allele frequencies over several generations
- usually happens when there are changes in environmental & therefore change in selection pressures, or a new allele has appeared in the population that’s advantages

23
Q

Example of directional selection:
-> process of steps using fish size as an example, as climate change selects for a smaller body size

A
  1. Warmer size = metabolism increases, more need for O2, and O2 decreases in warmer seas
  2. Large fish = disadvantaged is greater metabolic needs
  3. Organisms sensitive to temp changes, due to enzyme activities, therefore smaller fish = fitter = better adapted
  4. So smaller fish more likely to reproduce & their alleles for smaller size down
  5. Over time, inc freq of alleles for a small body size
24
Q

What is genetic drift

A

-> when chance (not environmental selection pressures) affects which individuals in a population survive therefore breed & pass on their alleles

25
Q

Example of genetic drift e.g. when the population is small, & chance can affect which alleles get passed onto the next generation, & therefore how over time, some alleles can be lost of favoured purely by luck

Example: if a small population of plants are at a playground with rubber sections & the allele for blue flowers = half the plants & the allele for pink = the other half

A

If most the pink seeds are blown to the rubber, and blue onto fresh soil, the allele for pink may disappear from population due to chance

26
Q

The […] the population , the bigger the impact of genetic drift

A

Smaller

27
Q

Substantial genetic drift leads to

A

Evolution

28
Q

What is genetic bottleneck

A

Occurs when a previously large population suffers a dramatic fall in numbers
- it can be due to major environmental effects e.g. disasters, climate change, etc, which reduce the number of individuals in a population which reduces the genetic diversity in the population as alleles are lost

  • surviving individuals breed & reproduce with close relatives
29
Q

What is founder effect

A

It only occurs when a small no. of individuals from a large parent population start a new population

-> the new population is only made up of a few, so only some of the total alleles are present (not the whole gene pool)

Therefore, change in allele frequency may occur in diff directions

30
Q

Hardy Weinberg principle is for what

A

Allele freq for monogenic inheritance

31
Q

What is the hardy Weinberg principle & it’s assumptions

A

That in a stable, non-evolving population, allele frequencies stay constant

  • large pop size
  • no mutations
  • no selection pressure
  • random mating
32
Q

Hardy weinberg principle equations

A
33
Q

What are the types of isolating mechanisms in the evolution of new species

A

Geographic mechanism (allopatric speciation)
Reproductive mechanisms (sympatric speciation)

34
Q

What is allopatric speciation

A

-> o.g. population split into two via (e.g.) formation of mountain ranges, rivers etc
-> now they can’t reproduce due to geographical barrier
-> now each population = diff adapting (diff beneficial mutations) & therefore change

35
Q

What is sympatric speciation

A
  • due to differences in behaviour, despite being in the same condition
    E.g. random mutation to impact courtship rituals, mating calls etc
  • therefore no reproducing & gene flow messed up!
36
Q

What is artificial selection

A

The process by which humans choose organisms with desirable traits & selective breed them together to enhance the expression of these desirable traits over time & over many generations
AKA selective breeding

37
Q

Process generally of selective breeding

A

Population shows phenotypic variation - there are individuals with diff phenotypes & the breeder selects the individual with a desired phenotype
-> another individual (with the desired one) = bred together
Offspring produced & those with desired phenotype are selected for further breeding, over many generations

38
Q

Examples of selective breeding in animals

A

Usually focuses on 1 characteristic, often to an extreme e.g.
- cows / sheep / chickens etc (yield of meat & milk & wool)
- domestic dogs

Issues = selective bred individuals more prone to ailments e.g. milk fever, udder inflammation

39
Q

Examples of selective breeding in plants

A
  • for characterises e.g.
    disease resistance in food crops, increased crop yield, good taste

E.g. wheat: breeding to introduce a fungus resistance allele from a different wheat species, now we have hybrid ones

40
Q

Ethical considerations of artificial selection

A
41
Q

Positive effects of generic manipulation

A
  • cures for fatal diseases
  • can be sold e.g. economic
  • creates pest resistance crops
  • GM crop resistance to climate change = no famine
42
Q

Negatives of genetic manipulation

A
  • farms in LIC’s can’t afford parents
  • unethical due to side effects
  • biowarfare potential
  • research = mass disease outbreak

Module 6 (7 decks)

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