Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

IB Biology > 5.2 Natural Selection > Flashcards

5.2 Natural Selection Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What is a way to describe the theory of natural selection?

A

Survival of the fittest

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

What does the theory of natural selection tell us?

A

It is not the strongest or most intelligent that survives but rather the ones that are most adaptive to change

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

What are the conditions which the process of natural selection responds to?

A
  • Inherited variation
  • Competition
  • Selection
  • Adaptations
  • Evolution
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does the mneumonic ICE AGE stand for and what is it for?

A

The key components to the process of natural selection

Inherited variation - exists within the population
Competition - results from an overproduction of offspring
Environmental pressures - Leads to differential reproduction
Adaptations - which benefit survival are selected for
Genotype frequency - changes across generations
Evolution - occurs within the population

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

Explain how inherited variation is a part of natural selection?

A

There is genetic variation within a population which can be inherited

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

Explain how competition is a part of natural selection?

A

There is a struggle for survival as species tend to produce more offspring than an environment can support

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

Explain how selection is a part of natural selection

A

Environmental pressures lead to differential reproduction within a population

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

Explain how adaptations are a part of natural selection?

A

Individuals with beneficial traits will be more likely to survive and pass these traits on to their offspring

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

Explain how evolution is a part of natural selection?

A

Over time there is a change in allele frequency within the population gene pool

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

What are the two ways variation can manifest?

A

Discontinuous or continuous

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

What is needed for natural selection and for a member of a species to differentiate?

A

Variation

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

What is discontinuous variation?

A

Distinct classes

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

What is continuous variation?

A

Range across a characteristic spectrum

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

What are the three ways genetic variation between individuals may occur?

A

Mutations
Meiosis
Sexual reproduction

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

What is a gene mutation?

A

A gene mutation is a change in the nucleotide sequence of a section of DNA coding for a specific trait

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

What does mutations form?

A

New alleles

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

What are the three forms of mutations?

A

Beneficial
Detrimental
Neutral

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

What are beneficial mutations?

A

Beneficial mutations change the gene sequence to create new variations of a trait

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

What is another name for beneficial mutations?

A

Missense mutations

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

What are detrimental mutations?

A

Detrimental mutations shorten the gene sequence to abrogate the normal function of a trait

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

What is another name for detrimental mutations?

A

Nonsense mutations

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

What are neutral mutations?

A

Neutral mutations have no effect on the functioning of the specific feature

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

What is another name of neutral mutations?

A

Silent mutations

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

How does meiosis promote variation?

A

By creating new gene combinations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are the two ways meiosis promotes variation?

A

Crossing over and independent assortment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What does crossing over involve?

A

Crossing over involves the exchange of segments of DNA between homologous chromosomes during prophase 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the result of the recombination during the crossing over?

A

All four chromatids that comprise the bivalent will be genetically different

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

When does the exchange of genetic material occur during crossing over?

A

Between non-sister chromatids at the chiasmata

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are recombinants?

A

Chromatids that consist of a combination of DNA derived from both homologous chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What will offspring with recombinant chromosomes have?

A

Unique gene combinations that are not present in either parent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the total number of combinations that can occur in gametes through independent assortment?

A

2n
where n = haploid number of chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

When homologous chromosomes line up in metaphase 1 their orientation towards the opposing poles is…

A

Random

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What does it mean that the orientation of each bivalent occurs independently?

A

Different combinations of maternal/ paternal chromosomes can be inherited when bivalents separate in anaphase 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Why will random fertilisation by an egg and sperm will always generate different zygotes?

A

Because meiosis results in genetically distinct gametes

34
Q

Despite shared parentage, individual offspring’s will typically show…

A

variation

35
Q

How does the Malthusian dilemma relate to natural selection?

A

Species tend to produce more offspring than the environment can sustainably support

36
Q

What causes competition for survival?

A

The fact that a stable population will inevitably outgrow its resource base leading to competition for survival

37
Q

What happens when there is an abundance of resources?

A

A population will grow according to its biotic potential

38
Q

What happens when there is more offspring in relation to competition?

A

There are less resources available to other members of the population

39
Q

What happens if there is less resources available to a population?

A

There will be a struggle for survival and an increase in the mortality rate

40
Q

What are adaptations?

A

Adaptations are features of organisms that aid their survival by allowing them to be better suited to their environment

41
Q

What are the different classifications of adaptations?

A

Structural
Behavioural
Physiological
Biochemical
Developmental

42
Q

What is a structural adaptation?

A

Physical differences in biological structures

43
Q

What is behavioural structures?

A

Differences in patterns of activity

44
Q

What are physiological adaptations?

A

Variations in detection and response by vital organs

45
Q

What are biochemical adaptations?

A

Differences in molecular composition of cells and enzyme functions

46
Q

What are developmental adaptations?

A

Variable changes that occur across the life span of an organism

47
Q

What do adaptations result in?

A

Differential reproduction within a species which allows natural selection to occur

48
Q

What enables biological adaptations to be passed on to offspring?

A

How they have a genetic basis

49
Q

Organisms with beneficial adaptations are more what?

A

More likely to survive long enough to reproduce and pass on these genes

50
Q

Organisms without beneficial adaptations are less likely to what?

A

Less likely to survive long enough to reproduce and pass on their genes

51
Q

What is variation within a population determined by?

A

The presence of alleles

52
Q

How are the alleles likely to be passed from parent to offspring by?

A

Via sexual reproduction

53
Q

What do alleles encode for?

A

Phenotypic polymorphisms of a particular trait

54
Q

What are the three different types of alleles?

A

Beneficial
Detrimental
Neutral

55
Q

What do beneficial alleles do?

A

Beneficial alleles better equip the organism to survive and produce more offspring

Encodes beneficial adaptations

56
Q

What do detrimental alleles do?

A

Detrimental alleles harm the survival prospects of an organism leading to fewer viable offspring

57
Q

How do neutral alleles affect an organisms survival prospects?

A

They don’t. They have no impact

58
Q

What causes the proportion of different alleles to change across generations?

A

Natural selection

59
Q

What are more likely to be passed into future generations and why?

A

Beneficial alleles because they improve reproductive prospects

60
Q

What are less likely to be passed onto future generations and why?

A

Detrimental alleles as they result in fewer offspring

61
Q

Why are allele frequencies in a population constantly evolving?

A

Because as environments change, what is classed as beneficial or detrimental may change

62
Q

What is adaptive radiation?

A

Adaptive radiation describes the rapid evolutionary diversification of a single ancestral line

63
Q

When does adaptive radiation occur?

A

It occurs when members of a single species occupy a variety of distinct niches with different environmental conditions

64
Q

What do members of a species do in response to different selection pressures?

A

Members evolve different morphological features/adaptations

65
Q

What is an example of adaptive radiation?

A

The variety of beak types seen in the finches of the Galapagos islands

66
Q

Why have finches specialised their beak shapes?

A

In accordance to their primary source of nutrition

67
Q

What is the native habitat of Darwin’s finches?

A

Daphne Major

68
Q

What changed the frequency of larger beak sizes?

A

An extended drought in 1977 by natural selection

69
Q

What was the product of the 1977 drought?

A

Finches with larger beaks were better equipped to feed on the seeds and thus produced more offspring with larger beaks

70
Q

What did finches that fed on seeds have and why?

A

Finches that feed on seeds possess compact, powerful beaks as larger beaks are better to crack larger seed cases

71
Q

What are antibiotics?

A

Antibiotics are chemicals produced by microbes that either kill or stop the growth of bacteria

72
Q

What are antibiotics commonly used for?

A

They are commonly used to treat bacterial infections

73
Q

What may cause a small proportion of bacteria to develop antibiotic resistant?

A

Gene mutation

74
Q

How will resistant bacteria reproduce?

A

Binary fisison

75
Q

What happens to the resistant bacteria when they are treated with antibiotics?

A

They will survive and flourish in the absence of competition from other bacteria

76
Q

How might antibiotic resistant bacteria confer resistance to susceptible strains?

A

By transferring plasmids via bacterial conjugation

77
Q

What has the introduction of antibiotic caused?

A

It has caused the antibiotic resistance gene to become more frequent

78
Q

What is an example of antibiotic resistance in bacteria?

A

Staphylococcus aureus (Golden Staph)

79
Q

What can golden staph cause?

A

infections to the skin (lesions and boils)

Serious infections (pneumonia and meningitis)

80
Q

How was golden staph traditionally treated?

A

With the antibiotic methicillin

81
Q

What is MRSA?

A

A bacterial strain that is resistant to the antibiotic methicillin

82
Q

What is done to treat infections caused by staphylococcus aureus?

A

An alternative antibiotic agent

83
Q

What happened to MRSA and MSSA?

A

MRSA proliferated
MSSA died out

IB Biology (57 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions