Genetics, Population, Evolution And Ecosystems 7 Flashcards
(84 cards)
1
Q
Define genotype
A
Genetic makeup of an organism and all alleles an indivudal possesses
2
Q
Define phenotype
A
Outward charecteristics expressed in an organism based on the genotype and environment
3
Q
What is a dominant allele
A
Always expressed in the phenotype
4
Q
What is a recessive allele
A
Only expressed in the phenotype when the dominant allele is absent
5
Q
What are homozygous Chromosomes
A
Identical alleles of the same gene
6
Q
What are heterozygous Chromosomes
A
Two different alles of the same genes
7
Q
What is monohybrid cross
A
Genetic inheritance cross of charectersitics determined by one gene
8
Q
Whar is dihybrid cross
A
Genetic inheritance cross for a charecterstic determined by two genes
9
Q
Who investigated Dihybrid inheritance using what
A
Mendel peas
10
Q
In genetic crosses, what must you to show
A
Parental phenotype
Parental genotype
Possible gametes
Offspring genotype
Offspring phenotype
Proportion of each phenotype
11
Q
Dihybrid inheritance Samsung notes
A
Why are we doing a2 content rn
12
Q
What are the 2 types of offspring during dihybrid inheritance
A
F1 offspring
F2 offspring
13
Q
What are autososomes
What is the 23rd pair
A
First 22 pairs of Chromosomes
Sex Chromosomes
14
Q
A
15
Q
Define codominant
A
Both alleles are actually dominant and are expressed in the phenotype
16
Q
What two effects does codoninance have on phenotype
A
Sometimes you can get a blend of two charecteristics
In some organisms both charecteristics occur in the phenotype
17
Q
A
18
Q
What are multiple alleles
A
When there are more than 2 alleles for the same gene in a population
19
Q
How many alleles can be inherited in a diploid organism
A
2
20
Q
What does the number of phenotypes depend on
A
Whether alleles are dominant, recessive or codominant
21
Q
Is Blood type O allele dominant or recessive
A
Recessive
22
Q
What does blood type refer to
A
Antigens present on the cell surface of red blood cells
23
Q
During blood transfusion, its important to avoid brining together corresponding antigens and antibodies WHY
A
To prevent agglutination
24
Q
A
25
What blood group is the universal recipient
AB
26
What blood group is the universal donor
O
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Why is AB the universal recipient
It has no antibodies in the plasma so they don't bind to antigens in donors red blood cells so no agglutination occurs
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Why is O the universal donor
It has no antigens on its red blood cells so antibodies can't bind to antigens so no agglutination occurs
29
Multiple Samsung notes
Yayaaaaa
30
31
What is a sex linkage inheritance
The allele is only found on the X chromosome but not on the y chromsome
32
33
Is Rh+ or Rh- dominant
Rh+
34
What Chromosomes do Females have
XX
35
What Chromosomes do Males have
XY
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37
What is autosomal linkage
Alleles for each gene linked on the same chromsome so will be inherited together
38
39
Is there crossing over and independent assortment in dihybrid or autosomal linkage
Dihybrid
40
Are charecteristics controlled by recessive alleles on the X chromsomee more common in Males or females
Males because the characteristics don't have a Homologous propion that could have a dominant allele to save them from it
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What is epistasis
Allele of one gene affects or masks the expression of another allele in the phenotype
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What is recessive epistasis
When the presence of two recessive alleles at the first locus prevent the expression of the allele at the second locus
45
What is dominant epistasis
Occurs when having atleast one allele of the gene at the first pocus will block the expression of the gene at the second locus
46
What type of inheritance has the ratio 9:3:3:1
Dihybrid
47
What type of inheritance has the ratio 9:4:3
Recessive Epistasis
48
What is the Hardy Weinberg principle
A mathematical model used to predict the allele frequency within a population
49
Define gene pool
All the alleles kf all the genes in a population
50
Define gene pool
All the alleles of all gbe genes within a population
51
Define population
Number of indivudals of the same species living in a habitat
52
Define allele frequency
The proportion of an allele within the gene pool
53
What is the assumption of the Hardy weinberg principle that makes it not perfectly accurate
It assumes that there will be no chnage in the allele frequency begween generations within a population
- No migration to introduce or remove alleles from the population
- No mutations to create new alleles
- No selection favouring particular alleles
- random mating
- The population is large
54
What ate the two equations used for Hardy weinbergs principle and give a key
p² + 2pq + q²
p + q = 1
p - frequency of dominant allele
q - frequency of recessive allele
p² - frequency of homozygous dominant genotype
2pq - frequency of heterozygous genotype
q² - frequency of homozygous recessive genotype
55
Genepool Samsung notes
Yehehajajqbwha
56
When is chi squared test used
Investigating differences between frequencies
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When do you use a student T test
Investigating difference between two means
58
When do you use a correlation coefficient
Investigating an association between two measurements
59
If the calculated value is greater than the critical value in chi squared test what does this show
Significant difference
Reject null hypothesis
60
Define population
Group of organisms of the same species living in the same area at the same time that can interbreed to make fertile offspring
61
Define Habitat
Part of an ecosystem in which a particular organism lives in
62
Define community
All the populations of different species in the same area at the same time
63
Define ecosystem
A community and the non living components of an environment (biotic and abiotic factors)Ecosystems can range in size from very small to very large
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Define niche
An organisms role within the ecosystem
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Define biotic factors
Impact of the interactions between organisms
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Biotic factors: What are two types of competition
Intra specific competition
Interpspecific competition
67
Define intraspecific competition
When members of the same species compete for the same resources in limited supply
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Define interspecific competition
When members of different species compete for the same resources in limited supply
69
State some examples of resources individuals compete for
Competing for mating is only in ...... competition
Habitat food Water light space
Competing for mating is only in intraspecific competition
70
Explain the graph that shows predator prey relationship
Predators eat prey so prey population reduces
Predators are now in greater competition with eachother for remains prey
Predator population falls
Fewer Predators so less prey eaten
Prey population increases
Predator population has more food so population increases
Cycle continues
71
What are the 3 patterns that graphs showing Predator prey relationship always follow
- The size of the Predator and prey populations both fluctuate
- The peak of the prey will always be higher than Predators
- The size of population will always change in prey and then Predators(lag time)
72
What are the 3 types of selection
Stabilising
Directional
Disruptive
73
Explain disruptive selection
The two extreme characteristics are favoured
Change in environment
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What can continued disruptive selection lead to
Speciation
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What is speciation
The process that creates new species
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When does speciation occur
When one original population of the same species becomes reproductively isolated. This isolation means that there are now two populations of the same species but they cannot breed together. This can result in the accumulation of differences in the gene pools to the extent that the two populations would be unable to interbreed to make fertile offspring and are therefore classed as two different species.
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What are the two types of speciation
Allopatric
Sympatric
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In allopatric speciation, what is the cause of reproductive isolation
Geographical barriers
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In allopatric speciation, what is the cause of reproductive isolation
Differences in behaviour
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Explain allopatric speciation
Within all populations there is genetic variation due to random mutations
A population could become geographically isolated Overtime which sperates the original population into two which are now unable to reproduce to the Geographical barrier. Both speerate populations will continue to accumulate different menenfical mutations kvertime to help them survive in their environments, which are likely to vary. Both populations will become so genetically different that they would be unable to interbreed to create fertile offspring. They are therefore classed as two diff species.
81
Explain sympatric speciation
Populations can become reproductivelt isolated due to differences in their behaviour.
Random mutation could mean performance of a different courtship ritual or for individuals to be fertile at different times of the year
Individuals will not reproduce together and there will be no gene flow between the two groups within the populations.
Overtime these reproductively isolated populations will accumulate different mutation to the extent their DNA is so different they cannot interbreed to create fertile offspring.
82
What is genetic drift
Change in allele frequency within a population between generations due to chance and not due to natural selection
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What is genetic drift caused by and what is not caused by
Caused by chance, not due to natural selection
84
What kind of genetic drift results in evolution
How long does genetic drift take to lead to evolution in small pop vs large pop
Substantial genetic drift
Small pop - few generations
Large pop - many generations
