Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biology Paper 2 > Genetics, Populations And Ecosytems > Flashcards

Genetics, Populations And Ecosytems Flashcards

(68 cards)

Start Studying
1
Q

What is a Genotype?

A

The genetic constitution of an organism.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a Phenotype?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does Homozygous mean?

A

Two copies of the same allele for a gene.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does Heterozygous mean?

A

Two different alleles for the same gene.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a recessive allele?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is a dominant allele?

A

An allele that is always expressed in the phenotype.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is codominance?

A

Two alleles are both dominant and both are expressed in the phenotype.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are multiple alleles?

A

More than two alleles for a gene.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is sex-linkage?

A

A gene located on the X chromosome in the non-homologous region.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is autosomal linkage?

A

Genes located on the same chromosome (not the X or Y chromosome).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is epistasis?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is a monohybrid?

A

The inheritance of one gene.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is Dihybrid inheritance?

A

The inheritance of two genes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is natural selection?

A

The process that leads to evolution in populations, resulting in species becoming better adapted to their environment.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is selection pressure?

A

Factors that affect the survival of an organism and are the driving force of natural selection.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is differential reproductive success?

A

Not all individuals are equally likely to reproduce, resulting in changes in allele frequencies within a gene pool.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is allele frequency?

A

The proportion of an allele in the population.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is 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 and leads to speciation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What does it mean to be reproductively isolated?

A

Two populations of the same species cannot breed together, resulting in no gene flow.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is speciation?

A

The process that results in the creation of new species.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is allopatric speciation?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is sympatric speciation?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is genetic drift?

A

The change in the allele frequency within a population between generations, occurring from one generation to the next. Substantial genetic drift results in evolution.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is a population?

A

A group of organisms of the same species occupying a particular space at a particular time that can potentially interbreed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is a habitat?
The range of physical, biological and environmental factors in which a species can live.
26
What is a community?
All the species in a particular area at a particular time.
27
What is an ecosystem?
A community and the non-living components of an area. They can range from very small to very large in size.
28
What is a niche?
An organism's role within an ecosystem, including their position in the food web and their habitat.
29
What is carrying capacity?
The maximum population size an ecosystem can support.
30
What are abiotic factors?
Non-living conditions of an ecosystem that impact survival.
31
What are biotic factors?
Interactions between organisms: interspecific and intraspecific competition and predation.
32
What is interspecific competition?
Competition between members of different species.
33
What is intraspecific competition?
Competition between members of the same species.
34
What is a 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 and to avoid bias.
36
What is a quadrat?
A frame that is 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) and randomly sample.
38
When would you use a line transect?
When sampling a non-uniform area. ## Footnote Example: a rocky shore.
39
What is a belt transect?
One tape measure is placed through an ecosystem that is not uniform, and the quadrat is placed at every position along a tape measure.
40
What is an interrupted belt transect?
One tape measure is placed through an ecosystem that is not uniform, and the quadrat is placed at set intervals along the tape measure.
41
What are the three measurements you can take when counting plants in a quadrat?
Density, percentage cover, frequency
42
What is density measurement?
When you count the individuals present.
43
What is frequency measurement?
Count how many squares out of the 100 contain the species you are investigating.
44
What is percentage cover measurement?
Investigator estimates the percentage of the entire quadrat covered with the species being investigated. ## Footnote 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?
To estimate the population size of motile organisms and the change in an ecological community over time.
46
What is a succession?
The process of change in an ecological community over time.
47
What is a primary succession?
A succession with a pioneer species colonising bare rock or sand. ## Footnote It is the first time the land is colonised.
48
What is a secondary succession?
A succession that occurs after a disruption that causes plants to be destroyed, where succession starts again but the soil is already formed.
49
When would you use mark-release-recapture?
To estimate the population size of motile organisms and the change in an ecological community over time.
50
What is a succession?
The process of change in an ecological community over time.
51
What is a primary succession?
A succession with a pioneer species colonising bare rock or sand. ## Footnote It is the first time the land is colonised.
52
What is a secondary succession?
A succession that occurs after a disruption that causes plants to be destroyed, where succession starts again but the soil is already formed.
53
What is a pioneer species?
The first species to colonise an area. ## Footnote e.g. lichen
54
What is a climax community?
The final seral stage in succession; the most stable stage.
55
What is humus?
A thin layer of soil that forms in early primary succession.
56
What is conservation of habitats?
Protecting habitats as a means to protect species; maintains habitats and food sources.
57
What creates genetic variation?
Mutations, crossing over in meiosis, independent segregation in meiosis, and random fertilisation of gametes.
58
What is selective advantage?
Individuals with alleles that make them more likely to survive in that environment.
59
What are the effects of stabilising selection?
The middle (median) trait has a selective advantage and continues to be the most frequent in the population. The range decreases as the extreme traits are lost over time.
60
What are the effects of directional selection?
One of the extreme traits has a selective advantage. It occurs when there is a change in the environment, and the modal trait changes.
61
What is disruptive selection?
Disruptive selection causes alleles for extreme traits and the middling trait allele to become less frequent. ## Footnote It leads to speciation.
62
What is evolution?
Evolution is a change in allele frequencies in populations over many generations.
63
Why is genetic drift important in small populations?
Genetic drift has a bigger proportional impact on allele frequency changes, resulting in evolution occurring more rapidly.
64
How would you randomly sample?
To randomly sample, place two tape measures at right angles to create a gridded area, use a random number generator for coordinates, place the quadrate at those coordinates, collect data, and 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.

Biology Paper 2 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions