Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

AH Biology > 2.3 Variation and Sexual Reproduction > Flashcards

2.3 Variation and Sexual Reproduction Flashcards

1
Q

Costs and benefits of sexual reproduction compared to asexual

A
  • males unable to produce offspring
  • genetic variation provides the raw material required for adaptation, so sexually reproducing organisms have better chances of survival under changing selection pressures
  • genetic variability of offspring reduces the chances that all will be susceptible to infection by parasites
  • only half of each parent’s genome
    passed onto offspring, disrupting successful parental genomes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q
  • males unable to produce offspring
  • only half of each parent’s genome passed onto offspring, disrupting successful parental genomes
A

disadvantages of sexual reproduction

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

costs and benefits of sexual reproduction relationship

A

benefits outweigh the costs due to an increase in genetic variation of the population

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

benefit of genetic variation

A

genetic variation provides the raw material required for adaptation, giving sexually reproducing organisms a better chance of survival under changing selection pressures

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

what explains the persistence of sexual reproduction

A

the red queen hypothesis

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

selecting for sexual reproducing hosts and parasites

A
  • hosts that are better able to resist and tolerate parasitism have greater fitness
  • parasites that are better able to feed, reproduce, and find new hosts have greater fitness
  • if hosts reproduce sexually, the genetic variability in their offspring reduces the chances that all will be susceptible by parasites
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

asexual reproduction

A

one parent can produce daughter cells and establish a colony of virtually unlimited size over time

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

one parent can produce daughter cells and establish a colony of virtually unlimited size over time

A

asexual reproduction

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

costs and benefits of asexual reproduction

A
  • whole genomes are passed on from parent to offspring
  • maintaining genome of parent is an advantage in particularly narrow, stable niches or when re-colonising disturbed habitats
  • offspring can be reproduced more often and in larger numbers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Example of asexual reproduction in eukaryotes

A
  • Vegetative cloning in plants
  • Parthenogenesis in lower plants and animals that lack fertilisation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q
  • Vegetative cloning in plants
  • Parthenogenesis in lower plants and animals that lack fertilisation
A

Examples of asexual reproduction in eukaryotes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Where is parthenogenesis more common

A

Cooler climates

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

What climates are disadvantageous to parasites

A
  • Cooler climates
  • Regions of low parasite density or diversity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q
  • Cooler climates
  • Regions of low parasite density or diversity
A

Disadvantageous to parasites

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

Asexual reproducing populations and adaptations

A

Not able to adapt easily to changes in their environment, but mutations can occur that provide some degree of variation and enable some natural selection and evolution to occur

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

Not able to adapt easily to changes in their environment, but mutations can occur that provide some degree of variation and enable some natural selection and evolution to occur

A

Asexually reproducing populations

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

What organisms often have mechanisms for horizontal gene transfer

A

Organisms that principally reproduce by asexual reproduction. Eg. Plasmids of bacteria and yeasts

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

What do organisms that principally reproduce by asexual reproduction. Eg. Plasmids of bacteria and yeasts have

A

Mechanisms for horizontal gene transfer between individuals

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

Why do organisms that primarily use asexual reproduction have mechanisms for horizontal gene transfer

A

Increase variation

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

Advantage of prokaryotes having horizontal gene transfer

A

Faster evolutionary change than in organisms than only use vertical transfer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What organisms have faster evolutionary change than in organisms than only use vertical transfer

A

Prokaryotes, because of horizontal gene transfer

24
Q

Meiosis

A

Division of the nucleus that results in the formation of haploid gametes from a diploid gametophyte

25
Division of the nucleus that results in the formation of haploid gametes from a diploid gametophyte
Meiosis
26
Chromosomes in diploid cells
Typically appear as homologous pairs
27
Homologous chromosomes
- same size - same centromere position - same sequence of genes at the same loci
28
- same size - same centromere position - same sequence of genes at the same loci
Homologous chromosomes
29
Meiosis I (9)
The chromosomes, which have replicated prior to meiosis I, each consist of two genetically identical chromatids attached at the centromere Chromosomes condense and the homologous chromosomes pair up Chiasmata form at points of contact between the non sister chromatids of a homologous pair and sections of DNA are exchanged This crossing over of DNA is random and produces genetically different recombinant chromosomes Spindle fibres attach to the homologous pairs and line them up at the equator of the spindle The orientation of the pairs of homologous chromosomes at the equator is random Independent assortment: each pair of homologous chromosomes is positioned independently of the other pairs, irrespective of their maternal and paternal origin The chromosomes of each homologous pale are separated and move towards opposite poles Cytokinesis occurs and two daughter cells form
30
The chromosomes, which have replicated prior to meiosis I, each consist of two genetically identical chromatids attached at the centromere Chromosomes condense and the homologous chromosomes pair up Chiasmata form at points of contact between the non sister chromatids of a homologous pair and sections of DNA are exchanged This crossing over of DNA is random and produces genetically different recombinant chromosomes Spindle fibres attach to the homologous pairs and line them up at the equator of the spindle The orientation of the pairs of homologous chromosomes at the equator is random Independent assortment: each pair of homologous chromosomes is positioned independently of the other pairs, irrespective of their maternal and paternal origin The chromosomes of each homologous pale are separated and move towards opposite poles Cytokinesis occurs and two daughter cells form
Meiosis I
31
Independent assortment
Independent assortment: each pair of homologous chromosomes is positioned independently of the other pairs, irrespective of their maternal and paternal origin
32
Meiosis II
each of the two cells produced in meiosis I undergoes a further division during which the sister chromatids of each chromosome are separated. Four haploid cells are produced
33
each of the two cells produced in meiosis I undergoes a further division during which the sister chromatids of each chromosome are separated. Four haploid cells are produced
Meiosis II
34
Meiosis I and II
The chromosomes, which have replicated prior to meiosis I, each consist of two genetically identical chromatids attached at the centromere Chromosomes condense and the homologous chromosomes pair up Chiasmata form at points of contact between the non sister chromatids of a homologous pair and sections of DNA are exchanged This crossing over of DNA is random and produces genetically different recombinant chromosomes Spindle fibres attach to the homologous pairs and line them up at the equator of the spindle The orientation of the pairs of homologous chromosomes at the equator is random Independent assortment: each pair of homologous chromosomes is positioned independently of the other pairs, irrespective of their maternal and paternal origin The chromosomes of each homologous pale are separated and move towards opposite poles Cytokinesis occurs and two daughter cells form each of the two cells produced in meiosis I undergoes a further division during which the sister chromatids of each chromosome are separated. Four haploid cells are produced
35
what can be determined by the presence of sex chromosomes
the sex of birds, mammals, and some insects
36
how to determine the sex of birds, mammals, and some insects
the presence of sex chromosomes
37
what determines the development of male characteristics in mammals
the SRY gene on the Y chromosome
38
importance of the SRY gene on the Y chromosome
determines the development of male characteristics in most mammals
39
heterogametic (XY) males
- lack most of the corresponding homologous alleles on the shorter (Y) chromosome - can result in sex-linked patterns of inheritance as seen with carrier females (XBXb) and affected males (XbY)
40
X chromosome inactivation
process by which one of the X chromosomes is inactivated
41
process by which one of the X chromosomes is inactivated
X chromosome inactivation
42
what happens to homogametic females
one of the two X chromosomes present in each cell is randomly inactivated at an early stage of development
43
in what organisms is one of the two X chromosomes present in each cell is randomly inactivated at an early stage of development
homogametic females
44
purpose of X chromosome inactivation
prevents a double dose of gene products, which could be harmful to cells
45
what prevents a double dose of gene products, which could be harmful to cells
X chromosome inactivation
46
X chromosome inactivation in tissues
since X chromosome inactivation in each cell is random, half of the cells in any tissue will have a working copy of the gene in question
47
hermaphrodites
- species that have functioning male and female reproductive organs in each individual - produce both male and female gametes - usually have a partner with which to exchange gametes
48
- species that have functioning male and female reproductive organs in each individual - produce both male and female gametes - usually have a partner with which to exchange gametes
hermaphrodites
48
benefit of being a hermaphrodite
if the chance of encountering a partner is an uncommon event, there is no requirement for that partner to be of the opposite sex
49
what species have the advantage that if the chance of encountering a partner is an uncommon event, there is no requirement for that partner to be of the opposite sex
hermaphrodites
50
what determines sex and sex ratio
environmental rather than genetic factors
51
environmental sex determination in reptiles
controlled by environmental temperature of egg incubation
52
what is controlled by environmental temperature of egg incubation
sex determination in reptiles
53
what can sex change within individuals happen because of
- size - competition - parasite infection
54
what can some species do to the sex ratio in response to resource availability
adjust the sex ratio
55
what do some species adjust the sex ratio as a result of
resource availability

AH Biology (7 decks)

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