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Evolutionary biology, LEC 141 > The nature of biological variation, lecture 6 > Flashcards

The nature of biological variation, lecture 6 Flashcards

1
Q

Macroevolution

A

Evolutionary change, over long periods of time, on a large scale.

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2
Q

Example of macroevolution

A

eg: the origin of new taxonomic groups

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3
Q

Microevolution

A

Basis of natural selection, whereby a population progressively adapts to its environment.
Change at or below species level

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4
Q

Example of microevolution

A

Change at/below species level, eg in a species

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5
Q

Advantages of asexual reproduction

3

A
  1. In the stable environment
  2. The best genotype is reproduced
  3. Uses less energy/quicker
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6
Q

Asexual reproduction

A

Occurs by mitosis and daughter cells are identical to the parent cells - they’re clones

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7
Q

Asexual reproduction,

extent of genetic variation

A

Little genetic variation occurs

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8
Q

Mitosis

A

Cell division that results in 2 daughter cells with the same number/kind of chromosomes as the parent cell

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9
Q

Four types of mitosis

A
  1. binary fission
  2. budding
  3. parthenogenesis
  4. vegetative reproduction and fragmentation
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10
Q

Binary fission

A

1 cell divides into 2 cells of similar/same size, both have same genetic material

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11
Q

Budding

A

New individuals split off from parent cell, both have the same genetic materal, bud cell = smaller

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12
Q

Parthenogenesis

A

Development of unfertilised egg, no genetic input from males, obligate in some species, facultive in others

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13
Q

Facultive meaning

A

optional

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14
Q

Obligate meaning

A

Only option/compulsory

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15
Q

Two types of vegetative reproduction

A
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16
Q

Chromosomes

A

‘gene carrying’ structure found in the nucleus

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17
Q

How many pairs of chromosomes do humans have?

18
Q

Homologous chromosomes

A

Carry genes controlling the same characteristics

19
Q

Phenotype

A 
observable characteristics
(which depend on an organisms' physical environment and its genotype)
20
Q

Allelles

A

Alternative forms of a gene

21
Q

Genes

A

comprised of DNA

22
Q

Alleles can be…

A 
dominant (B)
or recessive (b)
23
Q

Genotype

A

genetic makeup of an individual

24
Q

Karyotyping

A

Pairing and ordering of chromosomes

25
Q

Supercoiling

A

nearly every cell contains your whole genome, highly condensed/coiled

26
Q

Homozygous

A

Homologous chromosomes contain the same allele

27
Q

Heterozygous

A

Homologous chromosomes contain different alleles

28
Q

Sexual reproduction

A

by meiosis, haploid gametes formed, fuse to form a diploid zygote

29
Q

Advantages of sexual reproduction

2

A
  • produces a lot of variation, new combinations may work better than previous ones
  • in a changing environment, variation may promote overall survival
30
Q

Mutation
which levels can it occur at in sexual reproduction?
3

A

chromosome
allele
single-point mutations (SNP)

31
Q

Polyploidy

result of

A

mutiple sets of chromosomes,

error in meiosis/mitosis

32
Q

Autopolyploidy

A

when an individual has more than two sets of chromosomes, both of which are from the same parent

33
Q

Allopolyploidy

A

when an individual has more than two sets of chromosomes, these copies come from different parents

34
Q

What is autopolyploidy a result of?

A

single species genome duplication

35
Q

What is allopolyploidy a result of?

A

two different but related species, interbreed, hybridise and then the chromosome number doubles

36
Q

Polyploidy summary

6

A
  1. results in reproductive isolation
  2. ‘mating’ with parent would yield triploid offspring
  3. may be able to reproduce asexually
  4. less significant among animals as self-fertilisation and vegetative reproduction don’t usually occur
  5. common in plants
  6. 70% of all flowering plants, are thought to have orginated as a result of polyploidy
37
Q

Four types of chromosomal mutation

A

deletion
duplication
inversion
translocation

38
Q

Arisal of variation in sexual reproduction

A
  • separation of homologous chromosomes (1 into each cell)

- reduction process - sister chromatids separate = haploid gametes

39
Q

Molecular variation

3

A
  • variation can occur at DNA, RNA and protein level
  • can be determined by comparing DNA, RNA and key proteins
  • amino acid sequence of homologous proteins compared within or between species
40
Q

How much molecular variation is there between species?

A

substantial variation between species

41
Q

Most DNA is…

A

non-coding

42
Q

Reasons why offspring are genetically different to their parents?
3

A
  1. independent assortment of chromosomes in meiosis
  2. exchange of DNA between homologous chromosomes by crossing over in meiosis
  3. random fertilisation, zygotes contain chromosomes from two parents

Evolutionary biology, LEC 141 (11 decks)

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