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MISS ESTRUCH FLASHCARDS > TOPIC 7: GENETICS, POPULATIONS, EVOLUTION AND ECOSYSTEMS > Flashcards

TOPIC 7: GENETICS, POPULATIONS, EVOLUTION AND ECOSYSTEMS Flashcards

1
Q

Genotype

A

the genetic constitution of an
organism

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2
Q

Phenotype

A

the expression of the genetic
constitution
and its interaction with the
environment

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3
Q

Homozygous

A

two copies of the same allele for
a gene

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4
Q

Heterozygous

A

two different alleles for the
same gene

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5
Q

Recessive allele

A

An allele that is only expressed
if there are no dominant alleles
present

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6
Q

Dominant allele

A

An allele that is always
expressed in the phenotype

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7
Q

Codominance

A

two alleles are both dominant
both are expressed in the
phenotype

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8
Q

Multiple alleles

A

More than two alleles for a gene

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9
Q

Sex-linkage

A

a gene located on the X
chromosome
in the non-homologous region

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10
Q

Autosomal
linkage

A

genes located on
the same
chromosome
(not the X or Y
chromosome)

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11
Q

Epistasis

A

When one gene masks/modifies
with the expression of another
gene

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12
Q

Monohybrid

A

The inheritance of one gene

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13
Q

Dihybrid

A

The inheritance of two genes

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14
Q

Natural
selection

A

the process that leads to
evolution in populations
results in species becoming
better adapted to their
environment

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15
Q

Selection
pressure

A

factors that affect the survival
of an organism
the driving force of natural
selection

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16
Q

Differential
reproductive
success

A

not all individuals are equally
likely to reproduce
results in changes in allele
frequencies within a gene pool

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17
Q

Allele
frequency

A

The proportion of an allele in
the population

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18
Q

Disruptive
selection

A

Individuals with either extreme
trait are more likely to survive
and pass on their alleles
the middling trait allele
becomes less frequent
leads to speciation

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19
Q

Reproductively
isolated

A

Two populations of the same
species, but they cannot breed
together
there is no gene flow

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20
Q

Speciation

A

the process that results in the
creation of new species

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21
Q

Allopatric
speciation

A

Two populations become
reproductively isolated due to
being geographically separated
results in the formation of two
new species

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22
Q

Sympatric
speciation

A

Two populations become
reproductively isolated whilst in
the same location
e.g. due to changes in behaviour
results in the formation of two
new species

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23
Q

Genetic drift

A

the change in the allele
frequency within a
population between
generations
occurs from one
generation to the next
substantial genetic drift
results in evolution

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24
Q

Population

A

All the individuals of one
species in the same area at the
same time

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25
Habitat
The range of physical, biological and environmental factors in which a species can live
26
Community
all the species in a particular area at a particular time
27
Ecosystem
a community and the non-living components of an area they can range from very small to very large in size
28
Niche
An organism's role within an ecosystem their position in the food web and their habitat
29
Carrying capacity
The maximum population size an ecosystem can support
30
Abiotic factors
Non-living conditions of an ecosystem
31
Biotic factors
Impact and interactions between organisms
32
Interspecific competition
Competition between members of different species
33
Intraspecific competition
Competition between members of the same species
34
Predator-prey relationship
the interaction between predator and prey and how this affects their population sizes
35
When would you use random sampling?
when there is a uniform distribution of the plant species to avoid bias
36
Quadrat
a frame gridded or opened used to sample non-motile organisms
37
What must you do to ensure your samples are representative?
Take a large sample (at least 30) randomly sample
38
When would you use a line transect
When sampling a non-uniform area e.g. a rocky shore
39
Belt transect
one tape measure is placed through an ecosystem that is not uniform the quadrat is placed at every position along a tape measure
40
Interrupted belt transect
one tape measure is placed through an ecosystem that is not uniform the quadrat is placed at set intervals along the tape measure
41
The 3 measurements you can take when counting plants in a quadrat?
density percentage cover frequency
42
Density measurement
when you count the individuals present
43
Frequency measurement
count how many squares out of the 100 contain the species you are investigating
44
Percentage cover measurement
investigator estimates the percentage of the entire quadrat covered with the species that is being investigated standardise by counting 1% for every small square that is at least half covered by the plant
45
When would you use mark-release recapture?
Estimate the population size of motile organisms
46
What is a succession?
the change in an ecological community over time
47
What is a primary succession
a succession with a pioneer species colonising bare rock or sand the first time the land is colonised
48
What is a secondary succession?
there is a disruption that causes plants to be destroyed succession starts again, but the soil is already formed
49
Pioneer species
The first species to colonise an area e.g. lichen
50
Climax community
The final seral stage in succession the most stable stage
51
Humus
A thin layer of soil that forms in early primary succession
52
Conservation of habitats
Protecting habitats as a means to protect species maintains habitats and food sources
53
What is the advantage of managing succession?
Conserves a range of habitats and a range of food sources enabling a wider range of species to survive
54
Hardy-Weinberg principle
a mathematical model used to predict the allele frequencies within a population p^2 + 2pq +q^2 = 1
55
Assumptions of the Hardy-Weinberg principle
There will be no change in the allele frequency between generations within a population e.g. no deaths, births or migration
56
Assumptions of mark-release recapture
the marked individuals released distribute evenly after being released no migration no births or deaths
57
What creates genetic variation?
mutations crossing over in meiosis independent segregation in meiosis random fertilisation of gametes
58
Selective advantage
Individuals with alleles that make them more likely to survive in that environment
59
Effects of stabilising selection
the middle (median) trait has a selective advantage and continues to be the most frequent in the population range decreases as the extreme traits are lost over time
60
Effects of directional selection
one of the extreme traits has a selective advantage occurs when there is a change in the environment the modal trait changes
61
Effects of disruptive selection
alleles for the extreme traits and the middling trait allele become less frequent leads to speciation
62
Evolution
a change in allele frequencies in populations over many generations
63
Why is genetic drift important in small populations?
the impact of allele frequency changes has a bigger impact proportionally results in evolution occurring more rapidly
64
How would you randomly sample?
place two tape measures at right angles to create a gridded area use a random number generator to get coordinates place the quadrate at the coordinates and collect the data repeat at least 30 times
65
How would you sample using a line transect?
Place a tape measure at a right angle to the road/river/shoreline place quadrat every set distance meters (e.g. 5 metres) collect the data in each quadrat repeat placing the tape measure in parallel 30 times
66
What is the formula to calculate population size with mark-release recapture?
estimated total population = number of organisms initially caught x number of organisms in second sample / number of marked organisms recaptured
67
Describe the mark release- recapture method of sampling
an initial sample of the population is captured individuals are marked and released allow them time to randomly disperse a second sample is captured the total number captured in the second sample and the number recaptured with the marking are recorded
68
Describe the changes you would see in a succession
Abiotic factors become less hostile biodiversity increases becomes more stable

MISS ESTRUCH FLASHCARDS (8 decks)

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