evolution by natural selection Flashcards

1
Q

what is genetic diversity

A

the total number of different alleles in a. population which enables natural selection and is caused by many different combinations of alleles, mutations, crossing over in meiosis and independent assortment

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

why is genetic diversity beneficial

A

prevents extinction by having a range of alleles and phenotypes to survive disease and changes. some phenotypes are advantageous- can survive and adapt to

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

describe the process of natural selection (giraffe example)

A

random gene mutation creates a new allele for a long neck/ specific characteristic
the individual with the long neck have an advantage because they can reach more leaves
the giraffe is more likely to survive, reproduce, and pass on the favourable allele
this repeats over many generations and allele frequency increases

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

what is stabilising selection

A

if environmental conditions remain constant, natural selection favours organisms that are already well adapted new extreme phenotypes are selected against

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

what is directional selection

A

if environmental conditions change, natural selection favours organisms with alleles for an extreme phenotype

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

What happens is stabilising selection occurs

A

There will be more people with the average characteristic and extreme phenotypes will have died after natural selection

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

What is the correct way to draw a histogram

A

Bars don’t touch
Bars are different widths
Frequency density= frequency/ category range

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

Describe the process of antibiotic resistance

A

A random mutation causes an advantageous allele which makes it resistant to an antibiotic
The bacteria with the mutation are more likely to survive as they do not get destroyed by the antibiotic.
Bacteria asexually reproduce and pass on that allele due to binary fission onto its offspring
This occurs over the many generations and allele frequency increases so bacteria evolve to become resistant to antibiotics

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

What type of selection is antibiotic resistance?

A

Antibiotic resistance is directional is the mean has shifted from before and after selection population has become more resistant to antibiotics

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

Describe the process of binary fission

A

Bacterial cell organelles duplicate (plasma and circular DNA replicates)
Each copy of plasmids and circular DNA to opposite poles of the cell
The cell wall and membrane pinches cytoplasm splits and cell splits

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

How do you calculate how many times a bacteria has divided to result in a certain number

A

log 2 (number of bacteria) x minutes

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

How do you calculate how many bacteria there are after a certain number of divisions?

A

Number doubles each time
E.g 15 divisions
2 ^15 = 32,768

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

What is the zone of inhibition?

A

Area around an antibiotic on a Petri dish which has destroyed bacteria, leaving a clear circle

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

What does standard deviation tell us?

A

Standard deviation helps us know how spread out data is from the mean to work out if it is precise, it also tells us how precise measurements are how reliable measurements are and if two means are significantly different

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

How do you calculate the size of the zone of inhibition?

A

Measure the diameter of the circle
Half that number to get the radius
Calculate the area by doing pi R ^2

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

What is the definition of species?

A

Two organisms are of the same species if they can breed to produce fertile offspring which are able to produce a sperm or ovum

17
Q

What will happen if two animals of a different species breed?

A

The offspring will not be fertile

18
Q

If the offspring of two different species has an uneven number of chromosomes what will happen?

A

Chromosomes will not be able to line up in homologous pairs so meiosis can’t happen to produce gametes

19
Q

What is courtship behaviour?

A

Organisms can recognise individuals of the same species through courtship behaviours
These behaviours attract a mate of the same species, but of the opposite sex and form a pair bond

20
Q

Why is courtship behaviour important?

A

They are able to produce fertile offspring if not species would become extinct

21
Q

What are the factors of the classification system?

A

Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

22
Q

What is phylogenetics

A

Classification of organisms into group based on their evolutionary origins and relationships

23
Q

Evidence that we use for phylogenetic

A

Physical appearance
Courtship behaviour
DNA base sequence
Amino acid sequences in key proteins
Antibody variable region shapes

24
Q

Classification system is an example of what?

A

A hierarchy
It is made up of large groups broken down into progressively smaller groups with no overlapping

25
Q

What are the three ways in which courtship behaviour increases probability of successful mating/ producing fertile offspring?

A

Stimulates gamete production
Attracts the same species
Attracts opposite gender